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TUB 


MICROSCOPIC  ANATOMY 

OF 

THE    HUMAN     BODY, 

IN 

HEALTH  AND  DISEASE, 

ILLUSTRATED   WITH   NUMEROUS   DRAWINGS   IN   COLOUR. 


BY 

ARTHUR    HILL    HASSALL,    ffl.  B. 

Author  of  a  "  History  of  the  British  Fresh-water  Algae;"  Fellow  of  the  Liimajan  Society;  Member  of  the 

Royal  College  of  Surgeons  of  England ;  one  of  the  Council  of  the  London  Botanical  Society ; 

Corresponding  Member  of  the  Dublin  Natural  History  Society.  &c. 


ADDITIONS    TO   THE   TEXT   AND    PLATES, 

AND 

AN      INTRODUCTION, 

CONTAINING    INSTRUCTIONS   IN   MICROSCOPIC    MANIPULATION, 
BY 

HEJVRY  VANARSDALE,  M.  D. 

IN    TWO    VOLUMES. 

VOL.  I. 


NEW-YOEK; 
PRATT,    WOODFORD    &    CO. 

BOSTON  :   TICKNOR,  REED,  &  FIELDS ;    PHILADELPHIA  :   L1PPINCOTT   GRAMBO  &  CO. 
CINCINNATI :  H.  W.  DERBY  &  CO. ;   HARTFORD :   E.  C.  KELLOGG 

18  51. 


.ML?- 

/rr/ 


ENTERED,    ACCORDING    TO    ACT    OF    CONGRESS,    IN    THE    YEAR    1851,    BY 

E.   C.   KELLOGG, 

IN    THE    CLERK'S    OFFICE    OF    THE    DISTRICT    COURT   OF   CONNECTICUT. 


> 


FOUNDRY      OP 

PRESS     or 

SILAS    ANDRTTS    AND    SON, 

F.    C.    GUTIERREZ, 

HARTFORD. 

HEW-T03K. 

TO 


THOMAS   WAKLEY,    ESQ.,    I.  P., 


CORONER,    ETC.,    ETC. 


Dear    Sir: 

To  you  I  dedicate  the  accompanying  pages,  devoted  to 
the  elucidation  of  a  department  of  minute  anatomy  of  daily 
increasing  interest  and  importance. 

I  thus  dedicate  this  work  to  you  on  two  grounds;  the 
one  personal  and  private,  the  other  public. 

On  my  mentioning  the  design  of  this  work  to  you — and 
you  were  one  of  the  first  persons  to  whom  it  was  mentioned 
— you  were  kind  enough  to  express  yourself  in  terms  of 
approval  and  encouragement,  and  to  proffer  any  assistance 
in  your  power  in  the  furtherance  of  my  undertaking.  Of 
this  conduct  on  your  part  I  have  ever  entertained  a  pleasing 
and  grateful  remembrance;  and  it  is  this  which  constitutes 
the  private  ground  of  my  dedication. 

But  I  dedicate  this  work  to  you  on  a  higher  and  more 
important  ground.     I  have  for  many  years  seen  in  you  the 


DEDICATION, 


able  and  strenuous  advocate — amidst  much  obloquy  and 
misrepresentation — of  the  rights  of  that  profession  of  which 
we  are  both  members:  on  this  high  ground  I  conceive  you 
to  be  entitled  to  the  gratitude  of  your  professional  brethren; 
and  with  this  feeling  on  my  mind  of  your  conduct  and 
services  in  a  good  cause, 

I  beg  to  subscribe  myself, 

Yours,  very  faithfully, 

THE    AUTHOR. 


PREFACE  TO  THE  ENGLISH  EDITION. 


After  three  years  of  more  or  less  constant  labour,  the  welcome  and  often-wished- 
for  period  of  the  completion  of  this  work  has  arrived,  and  the  author  is  at  liberty  to 
address  himself  to  his  readers,  and  to  explain  the  motives  and  the  circumstances 
which  have  led  to  its  production. 

The  idea  of  this  work  presented  itself  to  the  author's  mind  several  years  since ;  it 
was  not,  however,  until  about  the  period  above  referred  to,  that  its  actual  execution 
was  commenced. 

At  the  time  when  its  design  was  first  conceived,  the  powers  of  the  microscope  in 
developing  organic  structure  were  but  beginning  to  be  known  and  appreciated,  and 
the  importance  of  its  application  to  physiology  and  pathology  was  but  dimly  perceived. 

At  that  period,  also,  but  few  complete  works  devoted  to  microscopic  anatomy  had 
appeared  in  any  language,  native  or  foreign;  more  recently  this  deficiency,  as  res- 
pects France  and  Germany,  has  been  well  supplied  by  the  appearance  of  several 
original  works,  as  those  of  Donne,  Mandl,  Lebert,  Miiller,  Henle,  Vogel,  Gerber,  and 
Wagner;  England,  however,  has  not  as  yet  contributed  her  share  of  distinct  and 
independent  works  on  general  anatomy :  not  that  our  observers  have  been  idle,  or 
have  neglected  a  field  of  inquiry  so  interesting  and  important,  resting  satisfied  with 
mere  translations:  a  whole  host  of  intelligent  and  able  microscopists  have  applied 
themselves  to  the  investigation  of  the  ultimate  structure  of  the  several  tissues  and 
organs,  and  this  with  a  preeminent  degree  of  success.  Among  the  more  remarkable 
of  these  investigators,  the  following  may  be  enumerated:  Gulliver,  Martin  Barry, 
Busk,  Addison,  Kiernan,  Sharpey,  Goodsir,  Tomes,  Toynbee,  Johnson,  Simon,  Todd 
and  Bowman,  Quekett,  Erasmus  Wilson,  Hughes  Bennet,  Carpenter,  Rainey,  Hand- 
held Jones,  and  Gairdner. 

The  results  of  the  labours  of  these  observers  have. not  as  yet,  however,  been 
embodied  in  a  separate  work ;  but  some  of  them  have  been  mixed  up  with  works  on 
descriptive  anatomy  and  physiology,  as  in  Sharpey's  edition  of  Quain's  Anatomy,  in 
Carpenter's  "  Principles "  and  "  Manual "  of  Physiology,  and  in  Todd  and  Bowman's 
"  Physiological  Anatomy."  The  last  is  an  admirable  book,  full  of  original  research 
and  important  facts. 

Now,  one  of  the  purposes,  the  accomplishment  of  which  has  been  attempted  in  the 
following  pages,  has  been  the  collecting  together  of  the  numerous  communications 
on  general  anatomy  to  be  found  scattered  through  the  pages  of  our  different  scientific 
periodicals,  and  their  combination  into  a  whole. 

The  further  objects  which  the  author  has  had  in  view  in  the  production  of  this 
work  have  been  simplicity  of  description,  fidelity  of  representation,  and  the  addition 
of  such  facts  and  particulars  as  have  occurred  to  himself  in  the  course  of  his  own 
investigations;  and  he  may  take  this  opportunity  of  observing,  that  in  but  few 
instances  has  he  written  upon  a  subject  without  previous  investigation. 


6  PREFACE     TO     THE     ENGLISH     EDITION. 

The  author  considers  it  right,  in  justice  to  himself,  that  certain  disadvantages  under 
which  the  work  has  been  produced  should  be  mentioned :  these  were,  constant 
engagement  in  general  practice,  much  anxiety,  and,  though  last,  not  least,  ill  health. 
These  would  have  been  sufficient  to  have  deterred  many  from  the  undertaking  alto- 
gether. Although  this  has  not  been  the  effect  upon  the  author,  yet  it  cannot  be 
questioned  but  that  they  have  operated  in  some  respects  to  the  disadvantage  of  the 
work ;  and  he  begs  that  it  may  be  taken  neither  as  the  measure  of  that  of  which 
the  subject  is  capable,  nor  of  the  author's  powers  of  observation  and  description 
exercised  under  more  favourable  circumstances  of  health,  leisure,  and  feeling. 

The  author  makes  these  few  remarks  not  in  order  to  deprecate  any  fair  criticism, 
but  simply  that  the  truth  in  reference  to  the  production  of  this  work  may  be  known 
in  justice  both  to  the  writer  and  the  reader. 

Having  said  thus  much  in  relation  to  the  work  itself,  the  author  has  now  the 
pleasing  task  of  returning  his  acknowledgments  to  those  who  have  in  any  way 
assisted  him  in  his  laborious  though  most  agreeable  task;  these  are  particularly  due 
to  the  following:  Mr.  Quekett,  Dr.  Handfield  Jones,  Professor  Sharpey,  Mr.  Tomes, 
Mr.  Bowman,  Mr.  Busk,  Professor  Owen,  Mr.  Canton,  Dr.  Carpenter,  Dr.  Letheby, 
Dr.  Robert  Barnes,  Mr.  Ransom,  Mr.  Pollock,  and  Mr.  Gray,  of  St.  George's  Hospital, 
Mr.  Hett,  and  Mr.  Andrew  Ross:  they  are  also  due  to  Mr.  Drewry  Ottley;  Dr.  Rad- 
cliffe  Hall;  Mr.  Coppin,  of  Lincoln's  Inn;  Messrs.  Welch  and  Jones,  of  Dalston; 
Mr.  Berry,  of  James-street,  Covent  Garden ;  Mr.  Cowdry,  of  Great  Torrington ;  Dr. 
Jones,  of  Brighton;  Dr.  Chambers,  of  Colchester;  Mr.  Milner,  of  Wakefield;  Mr. 
Walker,  of  St.  John's-street  Road;  Mr.  Ringrose,  of  Potter's  Bar;  Dr.  Halpin,  of 
Cavan ;  and  Mr.  H.  Hailey,  of  Birmingham. 

To  Dr.  Letheby  I  hope  shortly  to  have  a  second  opportunity  of  rendering  my 
thanks,  in  connexion,  viz:  with  the  work  on  crystals,  entitled  "Human  Crystallo- 
graphy," an  announcement  of  which  appeared  some  months  since,  and  towards  the 
completion  of  which  considerable  materials  have  already  been  collected. 

To  Mr.  Hett,  my  thanks  are  especially  due  for  having,  at  considerable  trouble  and 
inconvenience,  furnished  me  with  very  many  of  the  injections  required  to  illustrate 
Part  XV.  of  the  "Microscopic  Anatomy;"  these,  together  with  numerous  other 
injected  preparations  of  that  gentleman  which  I  have  seen,  have  been  of  first-rate 
quality;  and  the  microscopic  anatomist  has  reason  to  hail  the  advent  of  such  a  man 
to  the  cause  of  general  anatomy  with  the  highest  satisfaction. 

To  Mr.  Andrew  Ross,  on  this,  as  on  a  former  occasion,  I  have  to  express  my  obli- 
gations, Mr.  R.  having  at  all  times  furnished  me  with  any  information  I  might  require, 
as  well  as  provided  me  with  any  necessary  apparatus. 

Thus  much  for  friends.  If,  in  the  inditing  of  this  work,  I  have  made  a  single 
enemy,  I  am  sorry  for  it,  and  still  more  so  if  I  have  given  any  real  occasion  for  offence. 
If,  in  differing  from  other  observers  as  to  certain  facts  and  conclusions,  I  have 
expressed  myself  in  such  a  manner  as  to  wound  their  feelings,  as  in  one  or  two 
instances  I  fear  I  may  have  done,  I  much  regret  it:  the  differences  among  men  whose 
common  aim  is  the  knowledge  of  truth,  as  manifested  in  the  works  of  creation,  should 
never  be  deep  or  lasting;  for  this  community  of  purpose  should  ever  be  a  firm  bond 
of  union  between  such  men,  seekers  after  truth,  and  should  displace  from  their  minds 
the  lesser  and  grosser  feelings  of  rivalry  and  ill-will. 

Nottino  Hill,  July  27th,  1849, 


PREFACE, 


BY   THE    AMERICAN   EDITOR, 


The  Microscopic  Anatomy  of  Dr.  A.  H.  Hassall  is  offered  to  the  student  in  this 
department  of  Medical  Science,  as  the  only  completed  work  on  the  subject  in  the 
English  language. 

In  the  present  edition,  the  introduction  and  additions  to  the  text,  are  chiefly  of  a 
practical  nature;  this  feature,  it  is  hoped,  will  not  detract  from  the  high  scientific 
character  of  the  original  work,  but  will  give  it  some  additional  value  for  those  who 
wish  to  pursue  the  study  of  minute  anatomy,  by  the  aid  of  the  microscope. 

It  will  be  observed  that,  in  some  instances,  Dr.  Hassall's  views  differ  from  those  of 
other  writers.  Some  of  these  views  Dr.  Hassall  has  himself  modified,  and  made 
mention  of  the  fact  in  the  Appendix :  other  instances  of  difference  have  been  pointed 
out  by  the  editor;  others,  again,  and  these  are  chiefly  matters  of  opinion  on  disputed 
points,  have  not  been  alluded  to,  as  it  did  not  seem  desirable  to  extend  the  work,  by 
adducing  farther  conflicting  statements  on  unsettled  questions. 

The  ten  Plates  added  to  the  American  edition,  are  mostly  original,  and  from  the 
human  subject.  The  drawings  for  these  Plates  were  made  by  aid  of  one  of  Mr. 
Spencer's  excellent  microscopes,  which  was  obligingly  loaned  for  the  purpose  by 
Prof.  C.  R.  Gilman. 

For  some  of  the  specimens  illustrating  certain  points  of  anatomy  which  have  been 
figured,  the  editor  is  indebted  to  Mr.  Hett,  of  London,  so  well  known  to  micro- 
scopists  for  his  beautiful  preparations  of  healthy  and  diseased  structures.  For 
other  objects  of  value,  to  Drs.  Neill  and  Goddard  of  Philadelphia,  whose  minute 
injections  have  equalled  the  best  foreign  ones. 

Almost  all  the  drawings  were  made  by  Mr.  W.  R.  Lawrence  of  Hartford,  whose 
previous  experience  in  drawing  from  the  microscope,  contributed  greatly  to  the 


8  PREFACE      BY      THE     AMERICAN      EDITOR. 

accurate  representations  he  has  given.  Several  of  the  figures  in  Plates  LXXIV. 
and  LXXV.,  were  drawn  by  Mr.  H.  A.  Daniels,  who  is  well  known  to  the  profes- 
sion of  this  city  as  an  accomplished  anatomical  draughtsman. 

To  all  these  gentlemen,  as  well  as  to  Prof.  A.  Clark,  and  A.  S.  Johnson,  Esq., 
of  New-York,  for  valuable  hints  in  manipulation;  and,  lastly,  to  the  publishers, 
for  the  generous  manner  in  which  they  allowed  the  expensive  additions,  and  for 
the  excellent  style  in  which  they  have  issued  the  work,  the  editor  desires  to  tender 
his  acknowledgments. 

The  additions  to  the  text  are  inserted  at  the  end  of  the  Articles,  and  enclosed 
in  brackets. 

New-York,  112  West  Twenty-Second  Street,  ) 
May   1st,  1851.  ^ 


CONTENTS. 


INTRODUCTION. 

PAGE 

Its  Object 27 

Choice  of  a  Microscope 27 

Division  of  Subject 27 

I.  — MICROSCOPES  AND  THEIR  ACCESSORIES. 

Ross'  Microscope 29 

Powell  and  Lealand's  ditto 29 

Smith  and  Beck's  ditto 30 

Chevalier's  ditto 30 

Oberhauser's  ditto 30 

Brunner's  ditto      ........."•••  31 

Nachet's  ditto 31 

Spencer's  ditto 31 

Allen's  ditto 33 

Pike  and  Sons'  ditto 33 

Accessory  Instruments 33 

II,— PREPARATION    OF    OBJECTS. 

Of  Fluids      .        .               37 

Of  Solids         .                        38 

Fine  Injections 42 

Materials,  used  in 42 

General  Directions 42 

Injections  with  Turpentine       . .  42 

Ditto  with  Ether 43 

Ditto  by  Double  Decomposition 44 

Ditto  with  other  Materials 48 

III.— PRESERVATION    OF    OBJECTS. 

Different  Cements  used 49 

Glass  Slides  and  Cells 51 

Thin  Glass       .                          51 


10  CONTENTS. 

PAGE 

Thin-glass  Cells 54 

Drilled  ditto 54 

Tube  ditto 54 

Built-up  ditto 55 

Gutta-percha  ditto 55 

FLUIDS   FOR  MOUNTING   OBJECTS. 

Alcohol  and  Water 56 

Goadby's  Solutions 56 

Other  Fluids         .        ...        .        . 57 

METHODS   OF   MOUNTING   OBJECTS. 

The  dry  way 59 

In  Canada  Balsam  with  heat 60 

In  Fluid 62 

As  Opaque  Objects ' .        .        .  63 

Labelling  Slides 63 

Cabinets .          ....  64 


PART    I. 


FLUIDS    OF    THE    HUMAN    BODY. 

ARTICLE     I. 

The  Lymph  and  Chyle. — General  description  of  Lymphatics  and  Lacteals,  page  67. 
Characters  and  Structure  of  Lymph,  68.  Ditto  of  Chyle,  68.  Ditto  of  Fluid  of 
Thoracic  duct,  70.  Corpuscles  of  Thymus,  72.  Structure  of  Lymphatics,  76. 
Examination  of  Lymph  and  Chyle,  78. 

ARTICLE     II. 

The  Blood. — Definition,  80.  Coagulation  of  the  Blood,  without  the  Body,  80. 
Formation  of  the  Clot,  81.  Formation  of  the  Buffy  Coat  of  the  Blood,  83.  Cup- 
ping of  the  Clot,  85.  Coagulation  of  the  Blood  in  the  Vessels  after  Death,  86. 
Signs  of  Death,  86.  Globules  of  the  Blood,  88.  The  Red  Globules,  89.  The 
White  Globules,  100.  Molecules  of  the  Blood,  121.  Blood  Globules  of  Reptiles, 
Fishes,  and  Birds,  123.  Capillary  Circulation,  125.  Circulation  in  the  Embryo  of 
the  Chick,  129.  Venous  and  Arterial  Blood,  134.  Modifications  of  the  Blood 
Corpuscles  the  results  of  different  external  Agencies,  138.  Modifications,  the 
results  of  Decomposition  occurring  in  Blood  abandoned  to  itself  without  the  Body, 
139.    Modifications,  the  results  of  Decomposition  occurring  in  Blood  within  the 


CONTENTS.  11 

Body  after  Death,  139.  Causes  of  Inflammation,  140.  Pathology  of  the  Blood, 
142.  Importance  of  a  Microscopic  Examination  of  the  Blood  in  Criminal  Cases, 
164.     Examination  of,  169.     Preservation  of,  170. 

ARTICLE     ill. 

Mucus,  171.  General  characters,  171.  Mucous  Corpuscles,  174.  Nature  of  Mucous 
Corpuscles,  176.     The  Mucus  of  different  Organs,  179. 

ARTICLE     IV. 

Pus,  183.  General  characters,  183.  Identity  of  the  Pus  and  Mucous  Corpuscle,  183. 
Distinctive  characters  of  Mucus  and  Pus,  186.  Distinctions  between  certain  forms 
of  Mucus  and  Pus,  190.  Detection  of  Pus  in  the  Blood,  191.  False  Pus,  192. 
Metastatic  Abscesses,  193.     Venereal  Vibrios,  194. 

ARTICLE     V. 

Milk,  195.  Serum  of  the' Milk,  196.  The  Globules,  197.  Colostrum,  201.  Patho- 
logical Alterations  of  the  Milk,  203.  The  Milk  of  Unmarried  Women,  206.  The 
Milk  of  Women  previous  to  Confinement,  206.  The  Milk  of  Women  who  have 
been  delivered,  but  who  have  not  nursed  their  Offspring,  208.  Milk  in  the  Breasts 
of  Children,  208.  Different  kinds  of  Milk,  208.  Good  Milk,  210.  Poor  Milk, 
212.  Rich  Milk,  213.  Adulterations  of  Milk,  213.  Formation  of  Butter,  214. 
Modifications  of  Milk  abandoned  to  itself,  and  in  which  Putrefaction  has  com- 
menced, 215.  The  Occurrence  of  Medicines,  &c.  in  the  Milk,  217.  Examination 
of  Mucus,  Pus,  and  Milk,  217. 

ARTICLE     VI. 

The  Semen,  218.  Spermatozoa,  Form,  Size  and  Structure  of,  218.  Motions  of  the 
Spermatozoa,  225.  Spermatophori,  228.  Development  of  the  Spermatozoa,  229. 
The  Spermatozoa  essential  to  Fertility,  232.  Pathology  of  the  Seminal  Fluid,  234. 
Application  of  a  Microscopic  examination  of  the  Semen  to  Legal  Medicine,  237. 
Examination  of  Semen,  239. 

ARTICLE     VII. 

Saliva,  Bile,  Sweat,  Urine,  240.  The  Saliva,  241.  The  Bile,  242.  The  Sweat, 
243.     The  Urine,  245.    Pathology  of  the  Urine,  246.     Examination  of  Urine,  252. 


12  CONTENTS. 


PART  II. 


SOLIDS  OF  THE  HUMAN  BODY. 
ARTICLE  Y  III. 

Fat,  254.  Form,  Size,  and  Structure  of  the  Fat  Corpuscle,  254.  Distribution  of 
Fat,  259.    Disappearance  of,  261.     Injection  of  Fat-vesicles,  263. 

ARTICLE     IX. 

Epithelium,  Distribution  of,  264.  Tesselated  Epithelium,  Structure  of,  265. 
Conoidal  Epithelium,  naked  and  ciliated,  Structure  of,  267.  Development  and 
Multiplication  of  Epithelium,  271.  Nutrition  of  Epithelium,  272.  Destruction 
and  Renewal  of  Epithelium,  272.  Epithelial  Tumours,  275.  Examination  of 
Epithelium,  275. 

* 

ARTICLE     X. 

Epidermis,  Distribution,  Form,  Structure,  and  Development  of,  277.  Epidermis  of 
the  White  and  Coloured  Races,  279.  Destruction  and  Renewal  of  Epidermis, 
279.    Description  of,  according  to  Mr.  Rainey,  281.     Examination  of,  281. 

article    xi. 
The  Nails,  Structure  of,  282.    Development  of,  283.     Examination  of,  258. 

article    xii. 
Pigment  Cells,  Structure  and  Varieties  of,  286.     Study  of,  290. 

article    XI  II. 

Hair,  Form  of,  291.  Size  of,  292.  Structure  of,  292.  Growth  of,  297.  Regen- 
eration of,  297.  Nutrition  of,  299.  Distribution  of,  300.  Colour  of,  301. 
Properties  of,  302.  The  Hair  of  different  Animals,  303.  Method  of  making 
thin  sections  of,  305. 

article    XIV. 

Cartilages,  306.  True  Cartilages,  306.  Fibro-Cartilages,  309.  Nutrition  of  Car- 
tilage, 311.     Growth  and  Development  of  Cartilage,  312.     Study  of  Cartilage,  316. 

article    XV. 

Bone,  Structure  of,  317.  Growth  and  Development  of,  324.  Accidental  Ossification, 
332.     Preparation  of  Bone,  334. 


CONTENTS, 


ARTICLE     XVI. 


13 


Teeth,  Structure  of,  335.     Development  of,  339.     Caries  of,  344.     Tartar  on,  345. 
Method  of  making  sections  of,  345. 


ARTICLE     XVII 


Cellular  or  Fibrous  Tissue,  346.     Inelastic  or  White  Fibrous  Tissue,  346.     Elastic 
or  Yellow  Fibrous  Tissue  348    Development  of  Fibrous  Tissue,  352. 


ARTICLE     XVIII. 


Muscle,  354.  Structure  of  Muscle,  355.  Structure  of  the  Unstriped  Muscular 
Fibrilla,  355.  Structure  of  the-  Striped  Muscular  Fibre,  357.  Union  of  Muscle, 
with  Tendon,  362.  Muscular  Contraction,  363.  Development  of  Muscle,  367. 
Prof.  Kolliker  on  Unstriped  Muscle,  371.    Mode  of  preparing  for  examination,  375. 


article    XIX. 


Nerves,  376.     Structure  of,  376.     Cerebro- Spinal  System.     Secreting  or  Cellular 
Structure  of,  376.     Tubular  Structure  of,  378.    Sympathetic  System,  380.    Gelatin- 
Nerve,  Fibres  of,  380.     Structure  of  Ganglia,  383.     Origin  and  Termination 
of  Nerves,  384.     Pacinian  Bodies,  386.     Development  and  Regeneration  of  Nerv- 
ous Tissue,  388.    Researches  of  M.  Robin,  391.    Preparation  of,  for  examination,  394. 


ARTICLE     XX. 

Organs  of  Respiration,  395.  Aeriferous  Apparatus.  Bronchial  Tubes,  and  Air- 
Cells,  395.  Vascular  Apparatus,  398.  Pathology,  399.  Mr.  Rainey's  views  on, 
404.     Examination  of,  405. 

ARTICLE     XXI. 

Glands,  406.  Classification  of  Glands,  408.  a.  Follicles,  410.  Stomach  Tubes,  412. 
Fallopian  and  Uterine  Tubes,  413.  Solitary  Glands,  413.  Aggregated  Glands, 
414.  B.  Sebaceous  Glands,  414;  comprising  the  Meibomian  Glands,  416.  Glands 
of  Hair  Follicles,  416.  The  Caruncula  Lachrymalis,  418.  Glands  of  Nipple,  418, 
and  Glands  of  Prepuce,  418.  Mucous  Glands,  418;  including  the  Labial,  Buccal, 
Lingual,  Tonsilitic,  Tracheal,  and  Bronchial  Glands;  also,  the  Glands  of  the 
Uvula,  Brunner's  and  Cowper's  Glands,  418.  Brunner's  Glands,  421.  Coivper's 
Glands,  421.  c.  Salivary  Glands,  422.  Lachrymal  Glands,  423.  Mammary 
Glands,  423.  Liver,  Structure  of,  423.  Pathology  of,  432.  Examination  of,  435. 
Prostate  Gland,  436.  d.  Sudoriparous  Glands,  437.  Structure  and  examination 
of,  439.  Axillary  Glands,  441.  New  Tubular  Gland  in  Axilla,  Plate  LVIL,  fig. 
4  b.  Ceruminous  Glands,  441.  Kidneys,  442.  Secreting  Apparatus  of,  including 
Tubes,  Malpighian  Bodies,  and  Epithelial  Cells,  442.  Vascular  Apparatus  of,  444. 
Development   of  the  Kidney,  449.     Pathology   of,  453.     Examination   of,  482. 


14  CONTENTS. 

Testis,  483.  E.  Thymus  Gland,  484.  Thyroid  Gland,  486  Supra-renal  Capsules, 
488.  Spleen,  489.  i\  Absorbent  Glands,  492.  Villi  of  the  Intestines,  493. 
Examination  of,  496. 

ARTICLE     XXII. 

Organs  of  the  Senses,  497.  Touch:  .Papillary  Structure  of  the  Skin,  497. 
Examination  of,  500.  Taste  :  Papillary  Structure  of  the  Mucous  Membrane  of 
the  Tongue,  501.  Smell:  Structure  of  the  Mucous  Membrane  of  the  Nose,  505. 
Vision:  Structure  of  the  Globe  of  the  Eye,  509.  Sclerotic,  509.  Cornea,  510. 
Choroid,  514.  Retina,  518.  Vitreous  Body,  521.  Crystalline  Lens,  522.  Dissec- 
tion of  the  Eye,  533.  Hearing:  Organ  of,  523  External  Ear,  523.  Middle 
Ear,  523.     Internal  Ear,  525. 

APPENDIX. 

Pituitary  Gland,  535.  Pineal  Gland,  536.  Pia  Mater,  537.  Pacchionian  Glands, 
538.  Development  of  the  Fat  Vesicle,  538.  On  the  Structure  and  Formation  of 
the  Nails,  541.  On  the  Ganglionic  Character  of  the  Arachnoid  Membrane,  543. 
Structure  of  the  Striped  Muscular  Fibrilla,  547.  Structure  of  the  Bulb  of  the 
Hair,  547.     Synovial  Fringes,  547.     Structure  of  the  Sudoriparous  Glands,  547. 


IN-DEX  OF  THE  ILLUSTRATIONS, 


THE    WHOLE     OF     THE     FOLLOWING    ILLUSTRATIONS     AKE 
ORIGINAL     WITH     BUT     NINE     EXCEPTIONS: 


BLOOD. 

Corpuscles  of  man,  the  red  with  the  centres  clear,  670  diam 

The  same,  the  red  with  the  centres  dark,  670  diam. 

The  same,  seen  in  water,  670  diam.     . 

The  same,  the  red  united  into  rolls,  670  diam. 

Tuberculated  condition  of  the  red  corpuscles,  670  diam 

White  corpuscles  of  man,  in  water,  670  diam. 

Corpuscles  of  frog,  670  d'iam.        .... 

The  same,  with  the  nucleus  of  the  red  visible,  670  diam. 

The  same,  in  water,  670  diam. 

The  same,  after  prolonged  action  of  water,  670  diam 

Nuclei  of  red  corpuscles  of  frog,  670  diam. 

Elongation  of  red  corpuscles  of  ditto,  670  diam. 

Corpuscles  of  the  dromedary,  670  diam. 

The  same  of  the  siren,  670  diam.     .... 

The  same  of  the  alpaco,  670  diam. 

The  same  of  the  elephant,  670  diam. 

The  same  of  the  goat,  670  diam. 

Peculiar  concentric  corpuscles  in  blood,  670  diam.     . 

Coagulated  fibrin,  670  diam.         .... 

The  same  with  granular  corpuscles,  670  diam. 

Corpuscles  of  earth-worm,  670  diam. 

Circulation  in  tongue  of  frog,  350  diam. 

The  same  in  web  of  the  foot  of  ditto,  350  diam. 

Corpuscles  in  vessels  of  the  same,  670  diam.     . 

White  corpuscles  in  vessels  of  the  same,  900  diam. 

Glands  of  tongue  of  frog,  130  diam. 

Under  surfaee  of  tongue  of  same,  500  diam. 

Red  corpuscles  of  embryo  of  fowl,  670  diam. 

The  same,  in  water,  570  diam.  .         .         . 

Red  corpuscles  of  adult  fowl,  670  diam. 

The  same  of  young  frog,  670  diam. 

The  same  of  the  adult  frog,  670  diam. 

The  same  united  into  chains,  670  diam. 


I. 

Fig 

.  1 

I. 

" 

2 

I. 

" 

3 

I. 

" 

4 

I. 

it 

5 

I. 

" 

6 

II. 

« 

1 

II. 

" 

2 

II. 

" 

3 

II. 

" 

4 

II. 

" 

5 

II. 

" 

6 

III. 

it 

1 

III. 

" 

2 

III. 

" 

3 

IV. 

•' 

1 

IV. 

" 

2 

IV. 

" 

3 

IV. 

" 

4 

IV. 

" 

5 

IV. 

St 

6 

V. 

ts 

1 

V. 

" 

2 

VI. 

t< 

1 

VI. 

" 

2 

TO. 

" 

1 

VII. 

" 

2 

IX. 

" 

1 

IX. 

" 

2 

IX. 

« 

3 

IX. 

« 

4 

IX. 

" 

5 

IX. 

« 

6 

16 


INDEX     OF     THE     ILLUSTRATIONS. 


DEVELOPMENT   OF   EMBRYO    OF   CHICK. 


The  cicatricula  prior  to  incubation 

The  same  at  the  end  of  first  day  of  incubation 

The  same  at  the  thirty-sixth  hour     . 

The  same  at  the  close  of  the  second  day 

The  same  at  the  end  of  the  third  day 

The  embryo  on  the  conclusion  of  the  fourth  day 

The  same  at  the  termination  of  the  fifth  day 

The  embryo  of  six  days  old  .... 

The  embryo  of  the  ninth  day  of  development.    . 

The  same  at  the  end  of  the  seventh  day,  detached 

Ditto  at  the  end  of  the  ninth  day,  also  detached 


Plate 

X. 

Fig.  1 

<< 

X. 

"     2 

" 

X. 

"     3 

«  • 

X. 

"     4 

" 

X. 

"     5 

« 

X. 

"     6 

a 

X. 

«     7 

" 

X. 

"     8 

" 

X. 

"     9 

« 

X. 

"  10 

a 

X. 

«  11 

MUCUS. 

Corpuscles  of,  in  their  ordinary  condition,  670  diam. 

The  same  collapsed,  670  diam 

The  same,  showing  the  action  of  water,  670  diam. 

The  same  acted  on  by  dilute  acetic  acid,  670  diam. 

The  same  after  the  action  of  undilute  acetic  acid,  670  diam. 

The  same  in  process  of  development,  670  diam. 

Vaginal  mucus,  670  diam.  ...... 

^Esophageal  mucus,  670  diam.         ..... 

Bronchitic  ditto,  670  diam. 

Vegetation  in  mucus,  670  diam.       ..... 

Mucus  of  stomach,  670  diam . 

Vaginal  tricho-monas 

PUS. 

Corpuscles  of  laudable  pus,  670  diam.  . 

The  same  acted  on  by  acetic  acid,  670  diam.  .         . 

The  same  treated  with  water,  670  diam 

Epithelial  scales  from  pustule,  670  diam.  .         .         . 

Corpuscles  from  scrofulous  abscess,  670  diam.       .         .         , 
Vibrios  in  venereal  pus,  670  diam.  .... 


XI. 

tc 

1 

XI. 

ft 

2 

XI. 

" 

3 

XI. 

" 

4 

XI. 

" 

5 

XI. 

it 

6 

XII. 

" 

1 

XII. 

" 

2 

XII. 

" 

3 

xn. 

ft 

4 

XII. 

tt 

5 

XII. 

« 

6 

xrri. 

«     1 

xni. 

«    2 

XIII. 

<    3 

XIII. 

<    4 

xni. 

'    5 

xin. 

<    6 

MILK. 


Globules  of  healthy  milk  of  woman,  670  diam.     . 
The  same  of  impoverished  human  milk,  670  diam. 
Colostrum,  670  diam.  ..... 

Ditto,  with  several  corpuscles,  670  diam. 

Globules  of  large  size,  670  diam. 

Ditto,  aggregated  into  masses,  670  diam. 

Pus  in  the  milk  of  woman,  670  diam. 

Blood  corpuscles  in  the  human  milk,  670  diam. 

Globules  after  treatment  by  ether,  670  diam. 


The  same  after  the  application  of  acetic  acid,  670  diam. 


XIV. 

'  1 

xiv.    "    2 

XIV. 

'    3 

XIV. 

«     4 

XIV. 

«     5 

XIV. 

'     6 

XV. 

<     1 

XV. 

'     2 

XV. 

<     3 

XV. 

'    4 

INDEX     OF     THE     ILLUSTRATIONS, 


17 


Caseine  globules,  670  diam Plate     xv.  Fig.  5 

Milk  of  cow  adulterated  with  flour,  670  diam.         ....  "         xv.     "     6 


SEMEN. 

Spermatozoa  and  spermatophori  of  man,  900  diam. 
Spermatozoa  of  Certhia  familiaris  ..... 

FAT. 

The  fat  vesicles  of  a  child,  130  diam.  . 

Ditto  of  an  adult,  130  diam.  ...... 

Ditto  of  the  pig,  with  apparent  nucleus,  130  diam. 

Ditto  of  the  same,  ruptured,  130  diam.  .... 

Ditto  of  marrow  of  the  femur  of  a  child,  130  diam.     . 

Ditto,  with  the  membranes  of  the  vesicles  ruptured,  130  diam. 

Crystals  on  human  fat  vesicles,  130  diam.  .... 

Fat  vesicles  in  melicerous  tumour,  130  diam. 

Ditto  contained  in  parent  cells,  120  diam.  .... 

Ditto  after  the  absorption  of  the  parent  cell-membrane,  120  diam. 

EPITHELIUM, 


XVI. 
XVI. 


Buccal  epithelial  cells,  670  diam.        .... 

Cuneiform  ditto  from  duodenum,  670  diam. 

Ciliary  epithelium  from  trachea  of  frog,  670  diam. 

Human  ciliary  epithelium  from  lung,  670  diam. 

Ditto  from  trachea,  670  diam.  . 

Tesselated  epithelium  from  tongue  of  frog,  670  diam. 

Ditto  from  tongue  of  triton,  670  diam. 

Ditto  from  serous  coat  of  liver,  670  diam. 

Ditto  from  choroid  plexus,  670  diam. 

Ditto  from  vena  cava  inferior,  670  diam. 

Ditto  from  arch  of  the  aorta,  670  diam. 

Ditto  from  surface  of  the  uterus,  670  diam.     . 

Ditto  from  the  internal  surface  of  the  pericardium,  670  diam 

Ditto  of  lateral  ventricles  of  brain,  670  diam. 

Ditto  of  mouth  of  menobranchus  lateralis,  670  diam. 

EPIDERMIS. 

Upper  surface  of  epidermis,  130  diam. 

Under  surface  of  ditto,  130  diam 

Epidermis  of  palm,  viewed  with  a  lens  only, 

Ditto,  magnified  100  diam.         ...... 

Vertical  section  of  ditto,  100  diam.  .... 

Ditto  of  one  of  the  ridges,  100  diam.  . 

Epidermis  from  back  of  hand,  viewed  with  a  lens 
A  portion  of  same  more  highly  magnified,  100  diam. 
Epidermis  from  back  of  hand  100  diam. 
Ditto,  viewed  on  its  under  surface,  100  diam. 
Portion  of  ditto,  with  insertion  of  hairs,  100  diam. 

2 


XVIII. 

"    1 

XVIII. 

"     2 

XIX. 

"    1 

XIX. 

"    2 

XIX. 

"     3 

XIX. 

"     4 

XIX. 

"     5 

XIX. 

"     6 

LXIX. 

"  10 

LXIX. 

"  11 

XX. 

"    1 

XX. 

"    2 

XXI. 

«    1 

XXI. 

"     2 

XXI. 

"     3 

XXI. 

"     4 

XXI. 

"     5 

XXII. 

"     1 

XXII. 

"     2 

XXII. 

"     3 

XXII. 

«     4 

XXII. 

"     5 

XXII. 

"     6 

XXVI. 

"6e 

XXVI. 

"6d 

XXIII. 

"    1 

XXIII. 

«    2 

XXIV. 

"    1 

XXIV. 

«     2 

XXIV. 

«     3 

XXIV. 

'     4 

XXIV. 

t     5 

XXIV. 

<     6 

XXVI.       "       1 

xxvi.     "     2 

XXVI.       ' 

<     3 

18 


INDEX     OF     THE     ILLUSTRATION 


Ditto  from  back  of  neck,  670  diam. 
Detached  cells  of  epidermis,  670  diam. 
Cells  of  vernix  caseosa,  130  diam. 
Cells  of  ditto,  670  diam. 


Plate  xxvi.  Fig.  5 
"  xxvi.  "6a 
"  xxvi.  "6b 
"    xxvi.     "6c 


NAILS. 

Longitudinal  section  of  nail,  130  diam 

Ditto,  showing  unusual  direction  of  striae,  130  diam. 
Ditto,  with  different  distribution  of  striae,  130  diam. 
Transverse  section  of  nail,  130  diam.      .         .         .         . 
Cells  of  which  the  layers  are  formed,  130  diam.  and  670  diam. 
Union  of  nail  with  true  skin,  100  diam.  . 


PIGMENT    CELLS, 

Cells  of  pigmentum  nigrum  (human),  760  diam.  "    xxvu. 

Ditto  of  the  same  of  the  eye  of  a  pig,  350  diam "    xxvu. 

Stellate  cells  of  lamina  fusca,  100  diam "    xxvu. 

Ditto  more  highly  magnified,  350  diam. "    xxvu. 

Cells  of  skin  of  negro,  670  diam "    xxvu. 

Ditto  from  lung,  670  diam "    xxvu. 

Cells  in  epidermis  of  negro,  350  diam "    xxvu. 

Ditto  in  areola  of  nipple,  350  diam "    xxvu. 

Ditto  of  bulb  or  hair,  670  diam "  xxvm. 

HAIR. 

Bulb  of  hair,  130  diam.  .... 

Root  of  a  gray  hair,  130  diam. 

Cells  of  outer  sheath,  670  diam. 

Portion  of  inner  sheath,  350  diam. 

Stem  of  gray  hair  of  scalp,  350  diam. 

Transverse  section  of  hair  of  beard,  130  diam. 

Another  section  of  the  same,  130  diam. 

Fibres  of  the  stem  of  the  hair,  670  diam. 

Apex  of  hair  of  perineum,  350  diam. 

Ditto  of  scalp,  terminating  in  fibres,  350  diam.    . 

Ditto  of  same  with  needle-like  extremity,  350  diam 

Root  of  hair  of  scalp,  130  diam. 

Another  form  of  same,  130  diam.    . 

Hair  with  two  medullary  canals,  130  diam. 

Insertion  of  hairs  in  follicles,  100  diam. 

Disposition  of  hairs  on  back  of  hand. 

CARTILA  6E. 


Transverse  section  of  cartilage  of  rib,  350  diam. 
Parent  cells  seen  in  section  of  ditto,  350  diam. 
Vertical  section  of  articular  cartilage,  130  diam. 
Ditto  of  inter- vertebral  cartilage,  80  diam. 
Cartilage  of  concha  of  ear,  350  diam.    . 


XXV. 

'   1 

XXV. 

<     2 

XXV. 

'     3 

XXV. 

<     4 

XXV. 

'     5 

XXVI. 

'    4 

I 

'  2 
3 
'4a 
'4b 
'4c 
'  5 
'  6 
'     5 


It 

xxvm. 

"   1 

cc 

xxvm. 

"     2 

" 

xxvm. 

"     3 

it 

xxvm. 

«     4 

" 

XXIX. 

"    1 

" 

XXIX. 

"     2 

(C 

XXIX. 

"     3 

" 

XXIX. 

"     4 

« 

XXIX. 

"     5 

u 

XXIX. 

"     6 

" 

XXIX. 

"     7 

It 

XXIX. 

"     8 

CI 

XXIX. 

"     9 

« 

XXIX. 

"  10 

u 

XXVI. 

"     3 

« 

XXIV. 

'     5 

XXX. 

«   1 

XXX. 

•     2 

XXX. 

<     3 

XXX. 

'     4 

XXXI. 

•     1 

INDEX     OF     THE     ILLUSTRATIONS, 


19 


Cells  of  inter-vertebral  cartilage,  350  diam. 
Section  of  cartilage  and  bone  of  rib,  130  diam. 
Ditto  of  one  of  the  rings  of  the  trachea,  350  diam. 
Ditto  of  thyroid  cartilage  with  fibres,  130  diam. 
Cartilage  of  ossification,  100  diam. 
Section  of  primary  cancelli,  350  diam. 
Ditto  of  same,  more  advanced,  350  diam. 
Cartilage  of  ossification,  350  diam. 
Section  of  cartilaginous  epiphysis,  30  diam. 
Ditto  of  same,  with  bone,  30  diam. 
Ditto  of  same,  more  highly  magnified,  330  diam. 
Section  of  cartilage  and  bone  of  rib,  130  diam. 


Plate  xxxi.  Fig.  2 


XXXI.       ' 

'     3 

XXXI. 

'     4 

XXXI. 

«     5 

XXXIV. 

'    1 

XXXIV. 

'     2 

XXXIV. 

'     3 

XXXIV. 

'     4 

XXXV. 

'     1 

XXXV. 

'     2 

XXXV. 

«    3 

XXXV. 

'     6 

BONE. 

Transverse  section  of  ulna,  60  diam. 

Cross-section  of  Haversian  canals,  220  diam. 

Ditto  of  same  more  highly  magnified,  670  diam. 

Longitudinal  section  of  long  bone,  40  diam. 

Parietal  bone  of  fcetus,  30  diam. 

Portion  of  same  more  highly  magnified,  60  diam. 

Spicula  of  bone  of  foetal  humerus,  350  diam. 

Lamina  of  a  long  bone,  500  diam. 

Cancelli  of  long  bone  of  fcetus,  350  diam. 

Section  of  femur  of  pigeon  fed  on  madder,  220  diam. 

Section  of  epiphysis  and  shaft  of  foetal  femur,  100  diam, 

Transverse  section  of  primary  cancelli,  350  diam. 

Section  of  cancelli  more  advanced,  350  diam. 

Ditto  of  epiphysis  and  shaft  of  foetal  femur,  350  diam. 

Ditto  of  cartilaginous  epiphysis  of  humerus,  30  diam. 

Ditto  of  same  with  bone,  30  diam. 

The  same  more  highly  magnified,  330  diam. 

Blood-vessels  and  medullary  cells        .... 

Section  of  shaft  of  foetal  long  bone,  20  diam. 

Ditto  of  bone  and  cartilage  of  rib,  130  diam. 


XXXII.       ' 

•    1 

XXXII.       ' 

'     2 

XXXII.       ' 

'     3 

XXXII.       ' 

'     4 

xxxiii. 

'    1 

XXXIII. 

<     2 

XXXIII. 

'     3 

XXXIII. 

'     4 

XXXIII. 

'     5 

XXXIII. 

«     6 

XXXIV. 

'     1 

XXXIV. 

'    2 

XXXIV. 

«     3 

XXXIV. 

'     4 

XXXV. 

<     1 

XXXV. 

"     2 

XXXV. 

'     3 

XXXV. 

"     4 

XXXV. 

'     5 

XXXV. 

'     6 

TEETH. 

Vertical  section  of  incisor  tooth,  seen  with  lens 
Tubes  of  dentine  near  their  termination,  670  diam. 
A  not  unfrequent  condition  of  same,  670  diam. 
Tubes  of  dentine  near  their  commencement,  670  diam. 
Oblique  section  of  tubes  of  dentine,  670  diam. 
Transverse  section  of  ditto,  670  diam.    . 
Transition  of  tubes  into  bone  cells,  670  diam.   . 
Dilatation  of  ditto  into  bone  cells,  670  diam. 
Section  of  cementum,  670  diam. 
Ditto  of  same  traversed  by  tubes,  670  diam. 
Ditto  of  same  showing  angular  cells,  670  diam. 
Fungus  on  section  of  dentine,  670  diam. 
Oil-like  globules  on  section  of  same,  350  diam. 


xxxvi. 

<    1 

XXXVI. 

<     2 

XXXVI. 

'     3 

XXXVI. 

'     4 

XXXVI. 

'     5 

XXXVI. 

'     6 

XXXVI. 

'     7 

XXXVI. 

«     8 

XXXVII. 

'     1 

XXXVII. 

'    2 

XXXVII. 

«    3 

XXXVII. 

'    4 

xxxvii.     **    5 

20 


INDEX     OF     THE     ILLUSTRATIONS. 


Section  of  secondary  dentine,  350  diam. 
Ditto  of  bicuspid  tooth,  seen  with  lens  only 
Vertical  section  of  enamel,  220  diain.    . 
Enamel  cells  seen  lengthways,  670  diam. 
Cross-section  of  cells  of  enamel,  670  diam. 


Plate  xxxvu.  Fig.  6 
"  xxxvu.  "  7 
"  xxxix.  "  3 
"  xxxix.  "  4 
"    xxxix.     "     5 


FIBROUS    TISSUE. 

Longitudinal  section  of  tendon,  670  diam. "  xxxix.  "  1 

Transverse  section  of  same,  670  diam.           .....  "  xxxix.  "  2 

White  fibrous  tissue,  670  diam. "  xxxix.  "  6 

Mixed  ditto,  670  diam. "  xxxix.  "  7 

Yellow  fibrous  tissue,  670  diam.         ......."  xl.  "  1 

Different  form  of  ditto,  670  diam. "  xl.  "  2 

Development  of  blood-vessels,  350  diam.            .         .         .  ;               .  "  xl.  "  3 

Areolar  form  of  mixed  fibrous  tissue,  330  diam.      ....  "  xl.  "  4 

Blood-vessels  of  pia  mater,  350  diam. "  xl.  "  5 

Development  of  white  fibrous  tissue,  670  diam.      ....  "  xliii.  "  2 

Portion  of  dartos,  670  diam.     ........"  xliii.  "  3 

Section  of  corpora  cavernosa,  slightly  magnified     ....  "  xliii.  "  4 


MUSCLE. 

Portion  of  striped  muscle,  60  diam.  .         .         , 

Fragment  of  unstriped  ditto,  670  diam. 
Muscular  fibrillee  of  the  heart,  670  diam. 
Fragment  of  striped  muscle  of  frog,  350  diam. 
Fibres  and  fibrillae  of  voluntary  muscle,  350  diam. 
Fibres  acted  on  by  acetic  acid,  350  diam. 
Ditto  in  different  degrees  of  contraction,  350  diam. 
Union  of  muscle  with  tendon,  130  diam. 
Transverse  section  of  muscular,  fibres,  350  diam. 
Fibres  of  voluntary  muscle  of  fetus,  660  diam. 
Zigzag  disposition  of  fibres,  350  diam. 
Striped  muscular  fibre  and  fibrillae,  670  diam. 


XLI.       "       1 

XLI. 

'     2 

XLI. 

«     3 

XLI. 

'     4 

XLII. 

'     1 

XLII. 

'     2 

XLII. 

<     3 

XLII. 

(     4 

XLII. 

<     5 

XLIII. 

•     1 

XLIII. 

"     5 

XLIII. 

'     6 

NERVES. 

Tubes  of  motor  nerve,  670  diam 

The  same  after  the  action  of  spirit,  670  diam. 
The  same  after  the  action  of  acetic  acid,  670  diam. 
Portion  of  Casserian  ganglion,  350  diam. 
Nerve  tubes  of  cerebellum,  670  diam. 
Ditto  of  cerebrum,  with  clear  cells,  670  diam. 
Varicose  condition  of  ditto,  670  diam. 
Filaments  of  great  sympathetic,  670  diam.    . 
Cells  of  gray  matter  of  cerebellum,  670  diam. 
Ditto  of  same,  inner  stratum,  670  diam. 
Caudate  ganglionary  cells,  350  diam. 

(Spinal  cord,  Medulla  oblongata,  Cerebellum.) 
Ditto  from  locus  niger  of  cms  cerebelli,  350  diam. 


xliv. 

«       1 

XLIV. 

'     2 

XLTV. 

'     3 

XLIV. 

'     4 

XLIV. 

'     5 

XLIV. 

'     6 

XLIV. 

'     7 

XLV. 

'     1 

XLV. 

'     2 

XLV. 

'     3 

XLV. 

'     4 

INDEX     OF     THE     ILLUSTRATIONS. 


21 


Ditto  from  hippocampus  major,  350  diam. 

Ditto  from  locus  niger  of  crus  cerebri,  350  diam.  . 

Pacinian  bodies,  natural  size    . 

Ditto,  magnified  60  diam 

A  single  Pacinian  body,  100  diam. 

An  anomalous  Pacinian  body        .... 

Two  other  anomalous  Pacinian  bodies 

Cells  from  corpus  dentatum  of  cerebellum,  350  diam. 


"late  xlv. 

Fig 

G 

"            XLV. 

" 

7 

"          XLVI. 

" 

1 

"          XLVI. 

" 

2 

"          XLVI. 

" 

3 

"          XLVI. 

" 

4 

"         XLVI. 

" 

5 

"          XLVI. 

" 

6 

LUNG. 

Pleural  surface  of  lung,  30  diam 

Ditto,  with  vessels  of  first  order,  30  diam 

Ditto,  magnified  100  diam 

Section  of  lung  injected  with  tallow,  100  diam.     . 

Casts  of  air-cells,  350  diam 

Section  of  lung  injected  with  size,  100  diam. 
Pleural  surface  of  lung,  with  vessels  of  second  order,  100  diam. 
Section  of  lung,  with  air-cells  uninjected,  100  diam. 
Capillaries  of  lung,  100  diam.  .         .         .         . 


XLVII. 

<       1 

XLVII. 

'     2 

XLVII. 

•     3 

XLVIII. 

'     1 

XLVIII. 

'     2 

XLVIII. 

'     3 

XLIX. 

'     1 

XLIX. 

'     2 

XLIX. 

'     3 

GLANDS, 

Follicles  of  stomach,  with  epithelium,  100  diam. 
Ditto  of  large  intestine,  in  similar  condition,  100  diam 
Ditto  of  same,  without  epithelium,  60  diam. 
Termination  of  follicles  of  large  intestine,  60  diam. 
Follicles  of  Leiburkiihn  in  duodenum,  60  diam.     . 
Vessels  of  ditto  of  appendix  vermiformis,  100  diam. 
Ditto  of  same  of  stomach  of  cat,  100  diam. 
Stomach  tubes,  cross-section  of,  100  diam. 
Longitudinal  view  of  stomach  tubes,  220  diam.     . 
Ditto  of  the  same,  100  diam.  .... 

Villi  of  small  intestine,  with  epithelium,  100  diam. 
Ditto,  without  epithelium,  showing  lacteals,  100  diam. 
Vessels  of  villi  in  duodenum,  60  diam. 
Ditto  of  same  in  jejunum,  60  diam. 
Ditto  of  same  of  foal,  60  diam.    .... 
Solitary  glands%{  small  intestine,  natural  size 
Ditto  of  large  intestine,  slightly  magnified    . 
Aggregated  or  Peyer's  glands,  20  diam. 
Side  view  of  same,  20  diam.        .... 
Sebaceous  glands  in  connexion  with  hair,  33  diam. 
Ditto  from  caruncula  lachrymalis 
An  entire  Meibomian  gland,  27  diam.     . 
Illustrations  of  Mucous  glands,  45  diam. 
Parotid  gland  of  embryo  of  sheep,  8  diam.     . 
Ditto  of  human  subject,  further  developed,  40  diam. 
Mammary  gland,  portion  of,  slightly  magnified 
Ditto  of  same,  with  milk  globules,  90  diam. 


L. 

"       1 

L. 

'     2 

L. 

'     6 

L. 

'     7 

LII. 

"     5 

LI. 

"     1 

LI. 

"     2 

L. 

"     3 

L. 

«     4 

L. 

<     5 

LII. 

'     1 

LII. 

«     2 

LI. 

'    3 

LI. 

«     4 

LI. 

<     5 

LXII. 

'     6 

LI. 

'     6 

LII. 

<     3 

LII. 

'     4 

LIII. 

<     3 

LIII. 

<     1 

LIII. 

<     2 

LIII. 

'     4 

LIV. 

'     1 

LIV.      ' 

<    2 

LIV.      ' 

'    5 

LIV.      ' 

«    3 

22 


INDEX     OF     THE     ILLUSTRATIONS. 


Ditto  of  same  more  highly  magnified,  198  diam. 

Liver,  section  of,  showing  the  lobules,  35  diam.    . 

Surface  of  ditto,  showing  the  intra-lobular  veins,  15  diam. 

Section  of  liver  showing  the  hepatic  venous  plexus,  20  diam 

Vessels  of  portal  system,  20  diam.  .... 

Section  of  liver,  showing  inter-lobular  vessels,  24  diam. 

Surface  of  liver,  showing  portal  capillary  system,  20  diam. 

Ditto,  showing  both  hepatic  and  portal  venous  systems,  20  diam.  ■ 

Ditto,  with  both  systems  completely  injected,  20  diam. 

Ditto,  with  portal  vein  and  hepatic  artery,  18  diam. 

A  terminal  biliary  duct,  378  diam.  . 

Secreting  cells  of  liver  in  healthy  state,  378  diam 

Ditto,  gorged  with  bile,  378  diam. 

Ditto,  containing  oil  globules,  378  diam. 

Prostate  gland,  calculi  of,  45  diam. 

New  tubular  gland  in  axilla,  54  diam. 

Tubulus  of  ditto,  198  diam.     .... 

Ceruminous  glands,  portions  of,  45  diam.    . 

Sudoriferous  gland,  tubulus  of,  198  diam. 

Kidney,  tubes  of,  with  epithelium,  99  diam. 

Cross-section  of  elastic  frame-work,  99  diam.   . 

Ditto  of  frame-work  and  tubes,  99  diam.     . 

Section  of  vessels  in  tubular  part  of  kidney,  33  diam. 

The  same  vessels  seen  lengthways,  33  diam. 

Tubes  with  epithelium,  378  diam 

Corpora  Malpighiana  of  kidney,  injected,  40  diam. 
Uriniferous  tubes  of  a  bird,  40  diam.        .         .         . 
Corpora  Malpighiana  of  the  horse,  40  diam. 
Inter-tubular  vessels  of  surface  of  kidney,  90  diam. 
Transverse  section  of  injected  kidney,  67  diam. 
Uninjected  corpora  Malpighiana 

With  capsule,  100  diam. 

Without  ditto,  100  diam.  .... 

Malpighian  body,  more  highly  magnified,  125  diam. 
Afferent  and  efferent  vessels  of  Malpighian  tuft,  45  diam 
Epithelial  cells  of  the  tubes,  378  diam. 

Testis,  tubes  of,  27  diam 

Tubes  of  ditto,  more  highly  magnified,  99  diam. 

Vessels  of  thyroid  gland,  injected,  18  diam.     . 

Vesicles  of  ditto,  viewed  with  a  lens  only     . 

Ditto  of  same,  magnified  40  diam. 

Ditto  of  same,  showing  the  structure  of  their  walls,  67  diam. 

Lobes  and  vesicles  of  same  in  their  ordinary  condition,  27  diam. 

Nuclei  of  vesicles  of  thyroid,  378  diam 

Follicles  of  thymus,  with  vessels,  33  diam 

Capsule  of  ditto,  54  diam.  .         . 

Nuclei  and  simple  cells  of  same,  378  diam 

Compound  or  parent  cells  of  ditto,  378  diam. 

Spleen,  nuclei  and  vessels  of,  378  diam 


Plate 


L1V. 

Fig.  6 

LIV. 

«     4 

LV. 

"     1 

LV. 

"     2 

LV. 

"     3 

LV. 

u     4 

LV. 

"     5 

LVI. 

"     3 

LVI. 

"     4 

LVI. 

"     2 

LVII. 

"     1 

LVII. 

"2a 

LVII. 

"2b 

LVII. 

"  2c 

LVII. 

"    3 

LVII. 

"4a 

LVII. 

"  4b 

LVII. 

"     5 

LVII. 

"  4c 

LVIII. 

"     1 

LVIII. 

"     2 

LVIII. 

"     3 

LVIII. 

"    4 

LVIII. 

"     5 

LVIII. 

"     6 

LXIX. 

"     1 

LIX. 

"     2 

LIX. 

"    3 

LIX. 

"    4 

LIX. 

"     5 

LX. 

"    2 

" 

"       A 

tt 

"       B 

LX. 

"3a 

LX. 

"3b 

LX. 

"3c 

LX. 

"     1 

LX. 

"     4 

LXI. 

"     1 

LXI. 

«     2 

LXI. 

"    3 

LXI. 

"    4 

LXI. 

"     5 

LXI. 

"     6 

lxi: 

"     7 

lxi: 

"     8 

lxi: 

"     9 

lxi: 

"  10 

lxii: 

"     1 

INDEX     OF     THE     ILLUSTRATIONS. 


23 


Supra-renal  capsule,  plexus  on  surface  of,  54  diam.    . 

Tubes  of  ditto,  90  diam 

Nuclei,  parent  cells,  and  molecules  of  ditto,  378  diam. 
Vessels  of  supra-renal  capsule,  90  diam. 
Pineal  gland,  compound  bodies  of,  130  diam. 
Pituitary  gland,  cells  and  fibrous  tissue  of,  350  diam. 


Plate     lxii.  Fig.  2 


LXII. 

»  3a 

LXII. 

"  36 

LXII. 

"     5 

LXIX. 

«     7 

LXIX. 

"     8 

ANATOMY    OF    THE    SENSE     OF    TOUCH, 

Epidermis  of  palm  of  hand,  40  diam. " 

Ditto  of  back  of  hand,  40  diam " 

Papillae  of  palm  of  hand,  54  diam " 

Ditto  of  back  of  hand,  54  diam.    .         .         .         .         .         .  .  " 

Epidermis  of  palm,  under  surface  of,  54  diam.    ....  " 

Ditto  of  back  of  hand,  under  surface  of,  54  diam.  " 

Vessels  of  papilla?  of  palm  of  hand,  54  diam.      ....  " 

Ditto  of  same  of  back  of  hand,  54  diam.        ....." 


LXIII. 

tt 

1 

LXIH. 

tt 

2 

LXIII. 

tt 

3 

LXIII. 

" 

4 

LXIII. 

tt 

5 

LXIII. 

" 

6 

LXIII. 

it 

7 

LXIII. 

« 

8 

ANATOMY  OF  THE  SENSE  OF  TASTE. 

Filiform  papillae,  with  long  epithelial  appendages,  41  diam. 

Ditto,  with  shorter  epithelial  processes,  27  diam. 

Ditto,  without  epithelium,  near  apex  of  tongue,  27  diam.    . 

Ditto,  without  epithelium,  near  centre  of  same,  31  diam. 

Filiform  and  fungiform  papilla?,  without  epithelium,  27  diam. 

Peculiar  form  of  compound  papillae,  27  diam. 

Filiform  papillae  in  different  states,  27  diam. 

Ditto,  with  epithelium  partially  removed,  27  diam. 

Follicles  of  tongue,  with  epithelium,  27  diam.     . 

Ditto,  without  epithelium,  27  diam.         .... 

Ditto,  viewed  as  an  opaque  object,  27  diam. 

Filiform  papillae  from  point  of  tongue,  27  diam. 

Follicles  and  papillae  from  side  of  ditto,  20  diam. 

Simple  papillae,  with  epithelium,  45  diam. 

Filiform  papillae,  with  ditto,  18  diam. 

The  same,  viewed  with  a  lens  only         .... 

Side  view  of  certain  compound  papillae,  20  diam.         .         . 

Simple  papilla  from  under  surface  of  tongue,  54  diam.    . 

Compound  and  simple  ditto  from  side  of  tongue,  23  diam. 

A  calyciform  papilla,  uninjected,  16  diam. 

Ditto,  with  the  vessels  injected,  16  diam.    .... 

Filiform  papillae  near  centre  of  tongue,  injected,  27  diam. 

Ditto  near  tip  of  tongue,  injected,  27  diam. 

Simple  papillae,  injected,  27  diam.  .... 

Fungiform  ditto,  injected,  27  diam.     ..... 


LXIV. 

it 

1 

LXIV. 

" 

2 

LXIV. 

" 

3 

LXIV. 

" 

4 

LXIV. 

tt 

5 

LXIV. 

" 

6 

LXIV. 

" 

7 

LXIV. 

" 

8 

LXV. 

" 

1 

LXV. 

" 

2 

LXV. 

" 

3 

LXV. 

" 

4 

LXV. 

" 

5 

LXV. 

" 

6 

LXV. 

" 

7 

LXV. 

ft 

8 

LXV. 

tt 

9 

LXV. 

tt 

10 

LXV. 

" 

11 

LXVI. 

tt 

1 

LXVI. 

" 

2 

LXVI. 

tt 

3 

LXVI. 

" 

4 

LXVI. 

ft 

5 

LXVI. 

tt 

6 

ANATOMY    OF    THE    GLOBE    OF    THE    EYE. 


Vertical  section  of  cornea,  54  diam. 
A  portion  of  retina,  injected,  90  diam. 
Section  of  sclerotic  and  cornea,  54  diam. 


LXVII. 

tt 

1 

LXV1I. 

ft 

2 

LXVII. 

it 

3 

24 


INDEX     OF     THE     ILLUSTRATIONS 


Vessels  of  choroid,  ciliary  processes,  and  iris,  14  diam. 
Nuclei  of  granular  layer  of  retina,  378  diam. 

Cells  of  the  same,  378  diam 

Ditto  of  vesicular  layer  of  retina,  378  diam. 

Caudate  cells  of  retina,  378  diam.      .... 

Cells  of  the  membrana  Jacobi,  378  diam. 

Fibres  of  the  crystalline  lens;  a,  198  diam.  ;  6,  378  diam. 

A  condition  of  the  posterior  elastic  lamina,  78  diam. 

Peculiar  markings  on  same,  78  diam. 

Crystalline  lens  of  sheep,  slightly  magnified 

Fibres  of  lens  near  its  centre,  198  diam.    . 

Stellate  pigment  in  eye  of  sheep,  slightly  magnified 

Venae  vorticosae  of  eye  of  sheep,  injected 

Conjunctival  epithelium,  oblique  view  of,  378  diam. 

Ditto,  front  view  of,  378  diam.  .... 

Ciliary  muscle,  fibres  of,  198  diam. 

Gelatinous  nerve  fibres  of  retina,  378  diam. 

Cellated  structure  of  vitreous  body,  70  diam. 

Fibres  on  posterior  elastic  lamina,  70  diam. 

Portion  of  the  iris,  70  diam. 

Epithelium  of  crystalline  lens,  198  diam.  . 

Ditto  of  the  aqueous  humour,  198  diam. 

Hexagonal  pigment  of  the  choroid,  378  diam. 

Stellate  pigment  of  same,  378  diam.     . 

Irregular  pigment  of  uvea,  378  diam. 


Plate 

lxvii. 

Fig.  4 

11 

LXVII. 

"     5 

tt 

LXVII. 

"     6 

a 

LXVII. 

"     7 

tt 

LXVII. 

"     8 

a 

LXVII. 

"     9 

" 

LXVII. 

"  10 

" 

LXVII. 

"  11 

» 

LXVII. 

«  12 

" 

LXVII. 

"  13 

« 

LXVII. 

«  14 

It 

LXVIII. 

"     1 

" 

LXVIII. 

"     2 

" 

LXVIII. 

"     3 

" 

LXVIII. 

"     5 

tt 

LXVIII. 

"     4 

it 

LXVIII. 

"     6 

it 

LXVIII. 

"     7 

tt 

LXVIII. 

"     8 

" 

LXVIII. 

"     9 

it 

LXVIII. 

"  10 

(C 

LXVIII. 

"  11 

" 

LXVIII. 

"  12 

It 

LXVIII. 

"  13 

" 

LXVIII. 

«  14 

ANATOMY    OF    THE    NOSE 

Mucous  membrane  of  true  nasal  region,  80  diam. 

Ditto  of  pituitary  region,  injected,  80  diam 

Capillaries  of  olfactory  region  of  human  fetus,  100  diam. 


LXIX. 

"       1 

LXIX. 

"     2 

LXIX. 

"  12 

ANATOMY    OF    THE     EAR 

Denticulate  laminae  of  the  osseous  zone,  100  diam.    . 

Tympanic  surface  of  lamina  spiralis,  300  diam. 

Inner  view  of  cochlearis  muscle  of  sheep  . 

Plexiform  arrangement  of  cochlear  nerves  in  ditto,  30  diam. 


VILLI. 


Villi  of  foetal  placenta,  injected,  54  diam. 
Ditto  of  choroid  plexus,  45  diam. 


LXIX.       ' 

'     3 

LXIX.       ' 

<     4 

LXIX. 

'    5 

LXIX. 

'     6 

LXII.       ' 

'     4 

LXIX.     ' 

«     9 

Plates  "Vm.,  XVII.,  and  XXXVIII.,  omitted  in  the  original  edition,  are  likewise 
here  omitted.  The  same  numbers  for  the  other  plates  are  observed,  that  the  figures 
in  both  editions  may  correspond. 

The  Plates  added  to  the  American  Edition  commence  at  Plate  LXX. 


PLATES    ADDED 


TO 


THE     AMERICAN     EDITION 


Corpuscles  of  lymph,  800  diam Plate    lxx.  Fig.  1 

Corpuscles  of  chyle,  800  diam.                    .         .         .         .         .         .         "  lxx.  "  2 

Fat  vesicles,  injected,  45  diam.     .......             "  lxx.  "  3 

Transverse  sections  of  hair,  450  diam.      ......"  lxx.  "  4 

Cartilage  from  finger-joint,  80  diam.     ......             "  lxx.  "  5 

Vessels  of  synovial  membrane,  45  diam.  ......"  lxx.  "  6 

Injected  matrix  of  finger-nail,  10  diam.         .         .         .         .         .             "  lxxi.  " 

Vessels  of  tendon,  60  diam.     ........"  lxxii.  "  1 

Ditto  nearer  muscular  union,  30  diam. "  lxxii.  "  2 

Lymphatic  gland  and  vessels,  8  diam.       ......"  lxxiii.  "  1 

Capillaries  and  air-cells  of  foetal  lung,  60  diam.     ....             "  lxxiii.  "  2 

Ditto  of  same  of  child,  60  diam.       ......."  lxxiii.  "  3 

Ditto  of  same  of  adult,  60  diam.          ......             "  lxxiii.  "  4 

Branchia  of  an  eel,  60  diam .         "  lxxiii.  "  5 

Mucous  membrane  of  foetal  stomach,  60  diam.              .         .         .             "  lxxiv.  "  1 

Ditto,  showing  cells  and  cap.  ridges  of  adult,  60  diam.      ..."  lxxiv.  "  2 

Ditto  with  cells  deeper  and  ridges  more  elevated,  60  diam.    .         .             "  lxxiv.  "  3 

Ditto  showing  gastric  villi,  60  diam.          .                                                     "  lxxiv.  "  4 

Villi  of  duodenum,  60  diam.         .......             "  lxxiv.  "  5 

Ditto  of  jejunum,  60  diam.      ........"  lxxiv.  "  6 

Ditto  of  ileum,  60  diam.      ........            "  lxxv.  "  1 

Muscular  fibre  of  small  intestine,  60  diam.       ....."  lxxv.  "  2 

Appendix  vermiformis,  60  diam.           ......             "  lxxv.  "  3 

Mucous  follicles  of  colon,  60  diam.           ......"  lxxv.  "  4 

Malpighian  bodies  with  uriniferous  tubes,  of  adult,  100  diam.         .            "  lxxv.  "  5 

Ditto  enlarged  as  in  Bright's  disease,  100  diam.                                              "  lxxv.  "  6 

Enlarged  veins  of  kidney,  first  stage  of  Bright's  disease,  100  diam.           "  lxxvi.  "  1 

Ditto  of  same,  another  view,  100  diam.        .....             "  lxxvi.  "  2 

Stellated  veins  in  third  stage  of  same,  100  diam "  lxxvi.  "  3 

Granulation  on  the  surface  of  kidn  ;y,  100  diam.           ...             "  lxxvi.  "  4 

A  tube  much  dilated,  100  diam "  lxxvi.  "  5 

Sudoriparous  glands  and  their  ducts,  70  diam "  lxxvii.  "  1 

Ditto,  more  highly  magnified,  220  diam.          ....."  lxxvii.  "  2 


26 


INDEX     OF     THE     ILLUSTRATIONS 


Mucous  membrane  of  gall-bladder,  50  diam. 
Transverse  section  of  muscles  of  the  tongue,  45  diam. 
Terminal  vessels  in  cornea,  45  diam. 
Cornea  of  viper,  showing  its  vessels,  45  diam. 

Choroid  coat  of  foetal  eye,  45  diam 

Ciliary  processes  of  eye  of  adult,  45  diam. 
Mucous  lining  of  unimpregnated  uterus,  35  diam. 
Ditto  of  impregnated  uterus,  35  diam.    . 

Tuft  of  placenta,  GO  diam. 

Papillae  of  gum,  45  diam 

Ditto  of  lip,  45  diam. 

Blood-vessels  in  mucous  membrane  of  trachea,  45  diam. 

Ditto  of  buccal  membrane,  60  diam. 

Ditto  of  mucous  membrane  of  bladder,  60  diam.     . 


Plate 


LXXVII.  1 

<ig.  3 

LXXVII. 

"     4 

LXXVIII. 

"     1 

lxxviii. 

"     2 

LXXVIII. 

"     3 

LXXVIII. 

"     4 

LXXVIII. 

"     5 

LXXVIII. 

"     6 

Lxxrx. 

"     1 

LXXIX. 

"     2 

LXXIX. 

"     3 

LXXIX. 

"     4 

LXXIX. 
LXXIX. 

"     5 

INTRODUCTION. 


BY    THE    EDITOR. 


The  object  of  the  present  Introduction  is  to  furnish  some  practical  hints 
on  Manipulation  in  Microscopic  Anatomy,  so  that  the  student  who  is  dis- 
posed to  pursue  for  himself  this  subject,  and  has  not  at  his  command  other 
authorities,  may  be  provided  with  the  information  necessary  to  commence 
his  investigations. 

Although  plates  and  models  are  useful  as  companions  in  study,  and  as 
giving  more  explicit  views  of  authors  than  can  be  done  in  words,  yet  as 
these,  however  excellent,  can  never  make  the  student  master  of  special 
anatomy  without  dissection,  so  in  the  more  intricate  department  of  minute 
anatomy,  he  who  would  there  become  a  proficient,  must  investigate  for 
himself. 

The  same  remarks  apply  in  a  manner  to  specimens  prepared  by  others : 
these  seldom  receive  that  close  study  and  repeated  investigation  which  are 
willingly  given  to  one's  own  attempts.  The  very  admirable  preparations 
of  different  tissues  by  Hett,  Topping,  Darker,  and  others,  which  may  now 
be  purchased  of  many  opticians,  should  be  rather  regarded  as  standards  of 
success,  with  which  the  student  may  compare  his  own  efforts,  than  as  sub- 
stitutes for  his  own  manipulation. 

For  distinctness,  it  is  proposed  to  treat  the  subject  under  three  divisions : 

I.  Microscopes  and  their  Accessory  Instruments. 
II.   The  Preparation  of  Objects. 
III.  The  Preservation  of  Objects. 

I.  OF  MICROSCOPES  AND  THEIR  ACCESSORIES. 

It  will  not  fall  within  the  design  of  this  introduction,  to  treat  either  of 
the  theory  of  the  microscope,  or  its  construction.  A  brief  description  of 
the  various  forms  in  present  use  is  all  that  will  be  necessary. 

Those  only  who  have  studied  with  the  microscope,  know  the  comfort  and 
satisfaction  of  using  a  good  one;  and  by  this  is  meant  excellence  not  only 


28  INTRODUCTION. 

in  object-glasses,  although  these  are  the  most  essential  to  a  good  microscope, 
but  excellence  in  all  the  details  of  accessory  instruments,  and  in  nice 
mechanical  adjustment. 

It  is  a  very  common  error  to  suppose  that  cheap  microscopes  will  answer 
as  well  for  low  powers  as  more  expensive  ones :  that,  for  instance,  there  is 
no  difference  in  a  one-inch  object-glass  and  common  eye-piece  of  an  ordi- 
nary microscope,  and  the  same  focus  object-glass  and  eye-piece  of  a  good 
instrument :  hence  many  persons,  about  commencing  the  study  of  micro- 
scopic anatomy,  and  believing  that,  for  the  study  of  injected  preparations,  a 
power  of  one  hundred  diameters  will  in  most  cases  answer,  purchase  the 
cheapest  instrument  they  can  obtain,  with  that  degree  of  magnifying  power, 
unaware  that  penetration  and  definition  are  qualities  that  an  object-glass 
needs,  even  more  than  mere  magnifying  power — qualities  that  are  rarely 
found  to  exist  in  any  degree  in  the  cheaper  microscopes. 

It  is  in  these  qualities  that  the  English  and  American  instruments  excel 
the  French  and  other  continental  microscopes :  an  observer  with  the  former 
being  able  actually  to  see  more  of,  and  see  better,  the  construction  of  an 
object  with  a  glass  of  much  lower  magnifying  power :  the  object  being  in 
the  latter  case  clear  and  well  defined,  while  in  the  other,  though  more  highly 
magnified,  blurred  and  indistinct  with  poor  illumination.  It  is  a  great  satis- 
faction in  viewing  an  object  with  a  microscope  to  be  able  to  see  it  as  well 
as  any  one  has  hitherto  seen  it :  if  not  able  to  do  this,  one  always  feels  at  a 
disadvantage. 

An  error,  somewhat  similar,  committed  by  beginners,  is  in  supposing  that 
a  low-priced  microscope  (and  usually  therefore  a  poor  one)  is  sufficiently 
good  to  commence  with,  and  that  a  more  perfect  instrument  with  higher 
powers  may  be  purchased  when  more  familiar  with  its  use.  This  is  not 
only  poor  economy,  but,  as  already  stated,  such  an  instrument  gives  unsatis- 
factory and  often  false  views :  it  being  much  better  economy  where  this  is 
regarded,  and  infinitely  more  satisfactory,  to  purchase  a  good  instrument 
with  low  powers  at  a  fair  price,  to  which  the  higher  powers  may  be  added 
as  means  allow.  Those  who  can  afford  a  good  microscope,  and  yet  pur- 
chase a  poor  one,  commence  their  studies  under  great  disadvantages. 

It  must  not  be  forgotten,  however,  that  in  microscopic  observation,  more 
depends  on  the  observer  than  upon  the  instrument ;  more  upon  the  practised 
eye,  and  the  analytical  mind,  than  upon  the  precise  form  of  the  microscope 
or  the  number  of  its  accessories. 

The  following  brief  enumeration  of  the  different  prominent  microscope- 
makers  may  be  of  service  to  persons  at  a  distance  about  to  order  a  micro- 
scope, and  who  are  embarrassed  by  the  number  of  manufacturers,  and 
uncertain  about  the  expense. 

At  the  present  time,  the  most  elaborate  and  completely  furnished  micro- 


MICROSCOPES,     ETC.  29 

scopes  are  those  of  English,  and  especially  of  London  manufacture.  A  full 
account  of  the  various  forms  by  the  three  principal  London  makers,  is  given 
by  Mr.  Quekett  in  his  "  Practical  Treatise  on  the  Microscope."  He,  how- 
ever, does  not  give  preference  to  either. — Mr.  A.  Ross,  No.  2  Featherstone 
Buildings,  Holborn,  London,  is  usually  considered  the  most  prominent  of 
the  London  makers,  having  done  more  by  his  contributions  to  the  literature 
of  the  microscope,  and  his  various  improvements  in  its  form  and  accessory 
apparatus,  than  either  of  the  other  makers.  His  best  or  largest  microscope 
has  been  considered  to  be  unsurpassed  by  any  in  the  world.  Its  price  in 
London,  when  complete,  is  about  $450 ;  the  duty  on  importation  into  this 
country  being  30  per  cent,  ad  valorem.  As  has  been  mentioned  in  the 
preface  to  the  English  edition  of  the  present  work,  most  of  the  objects 
represented,  are  engraved  as  viewed  with  one  of  Mr.  Ross's  microscopes. 
Mr.  Ross  makes  several  forms  of  instruments,  among  which  the  most 
reasonable  in  price,  and  convenient  for  use,  is  one  described  in  the  Penny 
Cyclopedia,  article  "Microscope." 

This  instrument,  with  object-glasses  as  high  as  ith-inch,*  with  the  usual 
accessory  instruments,  may  be  obtained  in  England  for  about  $175. 

Messrs.  Powell  and  Lealand,  No.  4  Seymour-place,  Easton-square,  Lon- 
don, have  of  late  years  almost,  if  not  quite,  equalled  Mr.  Ross  in  the  excel- 
lence of  their  microscopes,  and  also  construct  several  forms.  One  of  the 
steadiest  and  most  convenient  is  the  second  size  described  by  Mr.  Quekett, 
on  page  77  (figure  44)  of  his  "Practical  Treatise." 

The  price  of  this  instrument  complete  is  about  $350  in  London,  and  to 
those  desiring  a  high-priced  instrument  the  writer  can  safely  recommend 
this  one,  as  combining  great  steadiness,  accuracy  of  adjustment,  and  excel- 

*  Note. — As  these  fractions  of  an  inch — ith,  |th,  ^th,  &c. — as  applied  to  the 
focus  of  object-glasses,  constantly  recur  in  this  introduction  and  elsewhere,  it  should 
be  stated  that  these  measurements  do  not  represent  the  actual  distance  between  the 
object  and  the  object-glass  in  each  particular  case,  but  are  used  to  signify  what  the 
distance  would  be,  if  a  single  lens  were  used  possessing  the  same  magnifying  power, 
instead  of  a  combination  (most  object-glasses  being  composed  of  three  lenses  instead 
of  a  single  one,  and  called  a  triplet)  :  in  other  words,  a  single  lens,  to  produce  the 
same  magnifying  power  as  a  ^th-inch  triplet,  would  have  to  be  a  lens  of  |th-inch 
focus.  This  nomenclature  is  unfortunate,  because  many  are  misled  by  it.  It  is, 
however,  in  general  use  in  England  and  in  this  country.  The  following  table  gives 
the  magnifying  powers  in  diameters  of  Mr.  Ross's  object-glasses  with  the  different 
eye-pieces.     The  objectives  of  other  makers  do  not  vary  much  from  these : 

OBJECT-GLASSES. 


EYE-GLASSES. 

2-IN. 

1-IN. 

flN. 

|-m. 

fm. 

t¥™ 

A.  or  long  eye-piece,  .  . 

.  20 

60 

100 

220 

420 

600 

B.  or  middle  eye-piece,  . 

.  30 

80 

130 

350 

670 

870 

C.  or  short  eye-piece, .  , 

.  40 

100 

180 

500 

900 

1400 

30  INTRODUCTION. 

lence  in  object-glasses.  It  is  a  most  luxurious  instrument  to  use.  Powell 
and  Lealand  construct  another  microscope,  having  the  supports  of  the  com- 
pound  body  and  the  stage  made  of  iron.  This  mounting  of  course  consider- 
ably  reduces  the  expense,  but  does  not  diminish  its  value  as  an  efficient 
instrument.  In  this  form  the  lever-stage  is  usually  employed,  and  a  micro- 
scope of  this  description,  with  object-glasses  as  high  as  ith,  may  be  imported 
for  about  $100  ;  but  this  sum  does  not  include  any  of  the  expensive  accesso- 
ries, such  as  the  achromatic  condenser  or  camera  lucida.  Powell  and  Lea- 
land  have  sent  several  of  these  instruments  to  this  country,  and  they  have 
given  great  satisfaction. 

Messrs.  Smith  and  Beck,  No.  6  Coleman-street  (city),  London,  though  less 
prominent  than  either  of  the  preceding  makers,  construct  several  excellent 
microscopes;  one  especially,  known  as  the  "Student's  Microscope,"  is  highly 
to  be  recommended  on  account  of  its  reasonable  price ;  being  furnished 
complete  with  all  the  accessories  for  about  $200,  and  combines  great  steadi 
ness  and  convenience  in  use.  The  same  instrument  with  plain  stage  and 
object-glasses  as  high  as  ith,  but  without  the  accessories,  may  be  had  in 
London  for  $75. 

Of  the  French  microscope-makers  the  most  prominent  have  hitherto  been 
M.  Chevalier  (163  Palais  Royal,  Paris,)  and  George  Oberhauser.  Cheva- 
lier's instrument  is  of  the  horizontal  form,  but  capable  of  being  converted 
into  the  vertical  or  the  inclined  one.  Though  the  microscope-stand  and 
apparatus  are  of  good  construction,  the  object-glasses  are  usually  defective 
in  definition :  such  at  least  is  the  character  of  most  of  those  imported  in  this 
country.  The  horizontal  form,  recommended  by  Sir  David  Brewster  as 
being  the  best  adapted  for  accurate  observation,  is  to  many  persons  fatiguing 
to  the  eye ;  and  the  image  of  the  object  being  a  reflected  one,  it  would  appear 
as  if  some  sharpness  of  outline  must  be  lost  by  the  reflection.  The  price  of 
one  of  Chevalier's  best  instruments  in  Paris  is  about  $200.  The  accessory 
apparatus  is  not  so  complete  as  with  the  English  instruments. 

A  smaller  size,  similar  in  construction,  and  usually  known  as  the  "small 
Chevalier,"  can  be  obtained  at  about  half  the  price  of  the  preceding  instru- 
ments; it  is  not,  however,  so  complete  in  object-glasses  or  accessories. 

The  form  that  Mr.  Oberhauser  (No.  19  Place  Dauphine,  Paris,)  adopts  is 
the  vertical  one  ;  a  form  of  construction  at  once  the  cheapest  and  least  com- 
plicated. His  microscopes,  though  often  ordered  from  this  country,  and  much 
used  on  the  continent  of  Europe,  have  two  important  faults;  the  first,  in 
common  with  M.  Chevalier's,  want  of  definition  and  penetration  in  the  object- 
glasses,  and  the  second,  inconvenience  of  mechanical  arrangement,  especially 
in  the  means  of  illumination ;  the  mirror  always  being  too  small,  and  inca- 
pable of  affording  oblique  light.  M.  Oberhauser  seems  to  rely  more  on  his 
short  eye-pieces  for  increasing  the   magnifying   power,  (there   sometimes 


MICROSCOPES,     ETC.  31 

being  five  or  six  of  these  furnished  with  his  microscope,)  than  upon  his  object- 
glasses  ;  a  great  mistake,  and  always  attended  by  loss  of  light  and  definition. 
The  more  one  studies  with  the  microscope,  the  more  one  learns  to  rely  on  the 
object-glass  for  power  and  less  on  the  eye-piece ;  objects  being  rarely  seen 
so  clearly,  and  therefore  not  so  well,  with  a  very  short  eye-piece  as  with  one 
from  two  to  three  inches  long.  Views  of  objects  afforded  by  M.  Oberhau- 
ser's  combination  of  object-glass  and  short  eye-piece,  producing  according 
to  his  own  table  a  magnitude  of  900  diameters,  are  far  less  satisfactory,  and 
show  less  of  minute  structure,  than  the  same  object  seen  with  an  English  ^th 
object-glass  and  long  eye-piece,  producing  a  magnitude  of  not  more  than 
220  diameters.  A  microscope  is  furnished  by  M.  Oberhauser  at  about  six 
months'  notice  for  $100,  with  a  power  according  to  his  own  measurement  of 
900  diameters. 

At  present,  the  best  French  microscope-makers  are  M.  Nachet  and  M. 
Brunner,  both  of  Paris.  The  microscopes  of  Nachet  (Rue  Serpente,  No.  16,) 
much  resembles  in  general  form  and  arrangement  the  large-sized  instru- 
ments of  M.  Oberhauser,  their  excellence  consisting  in  the  superiority  of 
their  object-glasses :  they  are  much  employed  in  microscopic  investigations 
in  Paris,  and  are  good  working  instruments ;  the  prices  are  about  the  same 
as  Oberhauser's,  but  the  object-glasses  are  every  way  superior. 

His  largest  sized  instrument,  complete,  is  sold  in  Paris  at  650  francs.  His 
smallest  size,  at  100  francs:  between  these,  are  several  intermediate  sizes. 

The  microscope  of  M.  Brunner  (Rue  des  Bernardins,  No.  34,  Paris,)  is 
also  a  vertical  one,  but  possesses  more  advantages  of  mechanical  arrangement 
than  any  other  of  the  same  construction ;  indeed,  it  almost  equals  the  more 
expensive  form  usually  adopted  in  England,  for  convenience  of  arrangement 
and  facility  in  use.  The  stage  is  large,  and  has  not  only  a  circular  motion, 
but  also  two  lateral  motions,  made  by  adjusting-screws;  the  mirror  is  large, 
and  admirably  arranged  for  affording  oblique  light.  The  object-glasses 
supplied  with  this  instrument  are  excellent,  and  for  sharpness  of  definition 
and  light,  are  hardly  surpassed  by  the  best  English  ones.  M.  Brunner 
also  supplies  the  achromatic  condenser,  the  polarizing  apparatus,  and  other 
accessories,  to  those  who  wish  them ;  and  his  prices  for  his  best  instruments 
vary  from  $90  to  $150,  according  to  the  powers  of  the  object-glasses  and 
accessories  furnished.  The  writer  has  no  hesitation  in  recommending  these 
microscopes  as  the  best  of  the  vertical  form,  possessing,  as  already  mentioned, 
more  advantages  of  mechanical  arrangement  than  any  other,  and  the  object- 
glasses  are  not  excelled  by  any  of  continental  make. 

The  rapid  advances  made  of  late  years  in  microscopic  knowledge,  have 
been  owing,  in  a  great  measure,  to  improvements  in  the  construction  of 
object-glasses.  To  this  end,  perhaps  nobody  has  contributed  so  much  as 
Mr.  Charles  A.  Spencer,  of  Canastota,  New-York.     The  objectives  made 


32  INTRODUCTION. 

by  this  gentleman  may  safely  bear  comparison  with  the  best  of  foreign 
make,  and  for  sharpness  of  definition,  power  of  penetration,  and  large  angle 
of  aperture,  are  not  excelled  by  any  in  the  world.  As  has  been  already 
stated,  much  of  the  excellence  of  an  object-glass  depends  on  its  power  of 
penetration :  this,  again,  depends  in  a  great  measure  on  the  angle  of  aper- 
ture by  which  the  rays  of  light  from  the  object  enter  the  glass.  It  must  be 
evident  that  the  greater  the  angle,  the  larger  must  be  the  pencil  of  rays. 
Mr.  Spencer  has  made  some  valuable  experiments  on  this  subject,  and  has 
been  enabled  to  obtain  a  curve  for  his  object-glasses,  by  which  in  the  yjth- 
inch,  he  can  give  an  angle  of  aperture  of  160°.  This  is  believed  to  be  the 
largest  angle  ever  given  to  an  object-glass :  the  greatest  obtained  by  Mr. 
Ross,  was,  for  a  Ty;h>  an  angle  of  135°,  and  the  one  usually  given  to 
object-glasses  of  the  same  focus  by  the  best  foreign  makers,  not  greater  than 
120°.  In  Mr.  Spencer's  ith-inch  object-glass,  the  angle  of  aperture  is  85°  ; 
in  the  -i-th-inch,  135°  ;  in  the  objectives  of  foreign  make,  according  to  Mr. 
Quekett,  the  angles  are  for  the  ^th-inch,  63s,  and  the  |th-inch,  80°. 

To  Mr.  Spencer  is  due  the  credit  of  having  first  resolved,  with  lenses  of 
his  own  construction,  the  fine  markings  on  the  Navicula  Spencerii  and 
Grammatophera  Subtillissima :  these  minute  shells  have  since  been  adopted 
by  microscopists  as  test-objects  for  the  highest  powers.  The  Navicula 
Spencerii,  will  exhibit  one  set  of  lines  with  Mr.  Spencer's  ith-inch  object- 
glass  :  both  sets  with  the  |th-inch.  The  Grammatophera  Subtillissima  is 
a  good  test  for  a  T\ih  or  TVth. 

Of  several  microscopes  made  by  Mr.  Spencer,  two  or  three  only  will  be 
here  noticed.  His  first-class  or  best  instrument  is  mounted  on  trunnions, 
and  embraces  all  the  acknowledged  improvements,  in  form  and  stage, 
whereby  the  greatest  steadiness  and  freedom  from  tremour  are  secured. 
The  price  of  this  instrument,  with  all  the  accessories  and  full  sets  of  object- 
glasses,  will  approach  $350. 

The  second-class  instruments,  complete  as  to  object-glasses  and  accesso- 
ries, but  mounted  less  expensively,  cost  from  $200  to  $250. 

A  very  efficient  microscope,  is  one  known  as  the  "Pritchard  form:"  this 
instrument  has  been  somewhat  modified  by  Mr.  Spencer,  and  where  a  less 
expensive  instrument  than  either  of  the  others  is  desired,  this  one  will  be 
found  a  good  working  instrument,  and  available  for  all  purposes  of  ana- 
tomical study.  The  cost  of  this  form,  with  object-glasses  as  high  as  the 
ith  with  the  usual  accessories,  is  from  $125  to  $150. 

Mr.  Spencer  also  makes  some  simpler  forms  of  instruments,  and  yet  very 
efficient  working  ones,  with  objectives  as  high  as  ith,  the  price  of  which 
does  not  exceed  $75. 

Mr.  Spencer  has  experienced  some  delay  in  the  completion  of  his  establish- 
ment, owing  to  the  difficulty  of  obtaining  efficient  workmen,  the  business 


ACCESSORY     INSTRUMENTS.  33 

being  in  this  country  comparatively  a  new  one,  and  for  which  it  was  neces- 
sary to  educate  men  and  invent  tools.  These  difficulties  are  now  overcome, 
and  his  establishment  is  in  active  operation. 

Mr.  J.  B.  Allen,  of  Springfield,  Mass.,  has  constructed  several  microscopes 
which  are  said  to  have  been  very  good  instruments,  both  as  to  model  and 
object-glasses.  The  form  is  somewhat  after  the  Pritchard  model,  in  which 
the  body  inclines  to  any  angle :  the  object-glasses  yet  made  have  been 
chiefly  of  low  and  medium  powers,  and  have  performed  very  satisfactorily. 

Messrs.  Pike  and  Sons,  opticians,  of  New  York,  construct  a  microscope- 
stand  of  great  steadiness  and  convenience  for  use,  the  supports  and  general 
appearance  of  which  much  resemble  the  large  instrument  of  Mr.  Ross. 
The  stage  is  large,  being  nearly  four  inches  square,  and  moveable  either  by 
adjusting-screws,  and  revolving  after  the  plan  described  by  Mr.  Legg,  or  is 
made  moveable  by  a  lever,  as  sometimes  employed  by  both  Powell  and 
Lealand,  and  Smith  and  Beck.  This  latter  stage  movement  is  very  exact, 
and  allows  of  quick  or  slow  motion  in  any  direction. 

The  mirror  is  large,  being  about  three  inches  in  diameter,  and  admirably 
arranged  for  oblique  light;  the  quick  motion  is  effected  by  rack-work,  and 
the  slow  motion  by  means  of  a  conical-pointed  steel  screw,  pressing  against 
the  top  of  a  slit  in  an  inner  tube,  furnished  with  a  spring :  at  the  end  of 
this  tube,  the  object-glasses  are  adapted. 

The  instrument  is  of  considerable  weight,  which  adds  to  its  steadiness, 
being  at  the  same  time  well  proportioned.  Its  price,  with  eye-pieces,  all  the 
accessories,  and  without  object-glasses,  is  about  $100. 

ACCESSORY   INSTRUMENTS. 

There  are  several  instruments  accessory  to  the  microscope,  and  most  use- 
ful in  dissection,  in  addition  to  those  usually  furnished  with  the  instrument. 

1.  Scalpels. — The  scalpels  of  the  dissecting-case  of  the  Medical  Schools 
will  be  necessary  in  making  the  ordinary  sections,  but  for  very  minute  dis- 
section, much  smaller-sized  instruments  will  be  found  useful.  The  blades 
of  these  may  be  either  straight,  curved,  lancet-shaped,  or  probe-pointed.  In 
default  of  any  instruments  for  this  especial  purpose,  the  small  knives  fur- 
nished with  the  case  for  operations  on  the  eye,  may  be  employed. 

2.  Dissecting  Forceps. — Small-sized  forceps,  both  straight  and  curved, 
are  among  the  instruments  most  often  required  in  minute  dissections. 
Those  with  exceedingly  fine  points,  and  at  the  same  time  made  true,  are 
especially  useful.     The  more  serviceable  forms  are  here  represented : 


34 


INTRODUCTION, 


Fig.  1. 


A  very  convenient  form  of  forceps,  is  one  known  as  the  cutting-forceps, 
and  is  represented  by  figure  2  : 


Fig.  2. 

The  sides  of  this  instrument  are  riveted  at  the  end,  as  those  of  the  ordi- 
nary forceps,  but  the  cutting  part  consists  of  two  scissor-shaped  blades, 
which  overlap  each  other,  and  are  prevented  from  crossing  over  too  far  by 
a  small  steel  pin ;  the  blades  are  bent  at  an  angle  with  the  sides,  and  by  this 
means  the  instrument  can  be  very  conveniently  employed  for  dissecting 
under  a  lens  of  half  an  inch  focus.  An  instrument  somewhat  resembling 
this,  and  called  the  microtome,  is  represented  at  figure  3  : 


"It  consists  of  two  sides,  like  a  pair  of  dissecting-forceps,  but  each  terminated  by 
a  scissor-shaped  blade,  arranged  so  that  its  cutting-edge  is  perpendicular  to  the  broad 
surface  of  the  sides,  in  order  to  prevent  the  blades  from  opening  too  wide;  a  screw 


ACCESSORY     INSTRUMENTS.  35 

with  a  fly-nut  is  attached  to  one  blade,  and  the  other  moves  freely  upon  it;  the  screw 
is  also  provided  with  another  nut,  situated  between  the  blades;  the  latter  may  be 
adjusted  so  as  to  prevent  the  blades  from  being  closed  beyond  a  certain  point,  while  the 
former  serves  to  regulate  the  space,  that  the  blades  may  be  kept  open  by  the  spring."  * 

This  instrument  is  a  very  useful  one,  on  account  of  the  great  precision 
with  which  any  tissue  or  filament  may  be  cut,  independent  of  any  tremour 
of  the  hand,  and  without  deranging  the  preparation. 

3.  Dissecting  Needles. — These  instruments  are  necessary  in  carrying  on 
dissection  of  delicate  tissues  under  the  microscope.  They  may  be  either 
curved  or  straight,  and  of  different  sizes.  Messrs.  Pike  and  Sons,  opticians, 
of  New  York,  furnish,  at  a  very  small  cost,  needle-holders,  in  which  the 
needles  may  be  changed  as  often  as  the  points  become  broken,  or  otherwise 
unfit  for  use.  Straight  needles  may  be  curved  by  heating  them  in  a  spirit- 
lamp  to  a  red  heat,  and  then  giving  them  the  desired  curve :  they  should  be 
then  again  heated,  and  dipped  in  cold  water  to  harden  them. 

4.  Valentin's  Knife. — This  instrument,  used  in  making  thin  sections  of 
soft  animal  tissues — like  the  liver,  spleen,  &c. — is  a  double-bladed  knife, 
the  flat  parts  of  the  blades  being  placed  against  each  other,  and  adjusted  by 
a  screw,  placed  below  the  cutting  portion  of  the  blades.  The  form  of  this 
knife  is  given  at  figure  4,  and  is  thus  described  by  Mr.  Quekett : 

JiiiiK 


Fig.  4. 

"This  consists  of  two  double-edged  blades,  one  of  which  is  prolonged  by  a  flat 
piece  of  steel  to  form  a  handle,  and  has  two  pieces  of  wood  riveted  to  it  for  the  pur- 
pose of  its  being  held  more  steadily;  to  this  blade  another  one  is  attached  by  a  screw; 
this  last  is  also  lengthened  by  a  shorter  piece  of  steel,  and  both  it  and  the  preceding 
have  slits  cut  out  in  them  exactly  opposite  to  each  other,  up  and  down  which  a  rivet, 
a,  with  two  heads,  is  made  to  slide,  for  the  purpose  either  of  allowing  the  blades  to 
be  widely  separated  or  brought  so  closely  together  as  to  touch ;  one  head  of  this 
rivet  is  smaller  than  the  hole  in  the  end  of  the  slit,  and  can  be  drawn  through  it,  so 
that  the  blade  seen  in  the  front  of  the  figure  may  be  turned  away  from  the  other,  in 
order  to  be  sharpened  or  to  allow  of  the  section  made  by  it  being  taken  away  from 
between  the  blades.  The  blades  are  constructed  after  the  plan  of  a  double-edged 
scalpel,  but  their  opposed  surfaces  are  either  flat  or  very  slightly  concave,  so  that 
they  may  fit  accurately  to  each  other,  which  is  effected  more  completely  by  a  steady 
pin  seen  at  the  base  of  the  front  blade.  When  this  instrument  is  required  to  be 
used,  the  thickness  of  the  section  about  to  be  made  will  depend  upon  the  distance 
the  blades  are  apart;  this  is  regulated  by  sliding  up  or  down  the  rivet,  a,  as  the 

*  Quekett's  "  Treatise  on  the  Microscope." 


36  INTRODUCTION. 

blades,  by  their  own  elasticity,  will  always  spring  open,  and  keep  the  rivet  in  place; 
a  cut  is  then  to  be  made  by  it,  as  with  an  ordinary  knife,  and  the  part  cut  will  be 
found  between  the  blades,  from  which  it  may  be  separated,  either  by  opening  tliem 
as  wide  as  possible  by  the  rivet,  or  turning  them  apart  in  the  manner  before 
described,  and  floating  the  section  out  in  water." 

Mr.  Hernstein,  cutler,  of  New  York,  has  made  a  modification  of  this 
instrument,  by  making  the  handle  curved  instead  of  straight:  this  form  has 
the  advantage  of  enabling  the  operator  to  hold  it  more  firmly  while  making 
the  section ;  it  has  the  disadvantage  of  not  allowing  him  to  use  the  cutting- 
edges  on  the  concave  side  of  the  curved  handle,  without  bringing  the  tissue 
to  be  cut  to  the  edge  of  the  table,  so  that  the  handle  has  room  to  play  below 
it.  Those  who  have  not  at  hand  one  of  these  instruments,  and  cannot  pro- 
cure one,  may  make  the  thin  section  with  a  sharp  scalpel  or  a  thin  razor. 

5.  Troughs. — Many  delicate  dissections  are  carried  on  underwater;  for 
this  purpose,  troughs  are  necessary  on  which  to  place  the  tissue  to  be  dis- 
sected. The  most  convenient  are  those  made  of  a  metal  frame,  about  three 
inches  Ions:,  two  wide,  and  one  inch  deep,  with  a  glass  bottom,  so  as  to  trans- 
mit the  light  when  necessary.  If  desired,  the  under  surface  of  the  glass  in 
one  of  the  troughs  may  be  blackened  with  sealing-wax-varnish,  or  a  piece 
of  black  silk  or  common  court-plaster  pasted  on. 

In  default  of  this  form  of  trough,  any  small  vessel  of  glass,  porcelain,  or 
metal  may  be  employed ;  a  small  evaporating-dish  answers  extremely  well. 
If  it  is  necessary  to  observe  the  object  by  means  of  transmitted  light,  of 
course  only  a  glass  trough  will  answer  the  purpose.  One  larger  trough, 
four  or  six  inches  square,  having  a  piece  of  flat  cork  half  an  inch  thick, 
(covered  with  black  cloth,  if  desired,)  and  secured  to  the  bottom  by  means  of 
the  marine  glue,  or  the  compound  cement,  so  that  the  tissue  under  dissec- 
tion can  be  fastened  with  pins  to  the  cork,  will  be  found  especially  useful. 
In  this  form  of  trough,  dissections  of  entire  insects,  such  as  beetles,  common 
cockroaches,  &c,  can  be  carried  on. 

6.  The  Compressor. — This  is  an  instrument  by  means  of  which  pressure 
may  be  applied  at  will  to  an  object  under  examination  with  the  microscope ; 
various  forms  are  in  use,  but  the  simplest  and  most  effectual  is  the  one  repre- 
sented in  figure  5 : 


Fig.  5. 


PREPARATION     OF     OBJECTS.  37 

"  This  instrument  consists  of  a  plate  of  brass,  three  or  more  inches  long  and  one 
and  a  half  broad,  having  in  its  middle  a  circular  piece  of  plate-glass  for  an  object- 
holder;  this  is  slightly  raised  above  the  metal  plate;  at  one  end  of  the  latter  is  a 
circular  piece  of  brass,  having  attached  to  it  another  piece  of  brass,  carrying  an  arm 
capable  of  being  moved  up  and  down,  by  means  of  a  screw  at  one  end,  while  at  the 
other  is  a  semi-circle,  supporting  by  screws  a  ring  of  metal,  to  the  under  side  of 
which,  a  piece  of  thin  glass  is  cemented."  * 

The  use  of  the  instrument  is  to  produce  a  pressure  upon  the  object 
between  the  plates  of  glass  while  being  examined  with  the  microscope ;  the 
compressor  being  placed  upon  the  stage  of  the  instrument.  The  object  is 
placed  upon  the  under  plate  of  glass,  the  arm  being  made  to  turn  away  for 
that  purpose. 

7.  Pipettes. — These  are  fine  glass  tubes,  about  eight  or  nine  inches  in 
length,  either  straight,  and  of  the  same  calibre  throughout,  or  curved  or 
drawn  to  a  fine  point  by  means  of  heat  from  a  spirit-lamp.  They  are  useful 
in  applying  the  different  reagents  to  the  objects  under  examination,  and  also 
for  collecting  any  required  portion  of  fluid — as  urine,  pus,  &c. — and  placing 
it  in  the  desired  position  for  examination.  They  are  among  the  most  useful 
of  the  minor  accessory  instruments,  and  can  be  fashioned  in  any  shape  by 
the  student  himself. 

A  few  only  of  the  accessory  instruments  that  may  be  used  in  minute 
anatomy  have  been  here  described.  There  is  much  truth  in  the  observation 
of  Rudolph  Wagner,  that  the  more  one  observes  with  the  microscope,  the 
more  he  learns  to  rely  on  the  simplest  instruments;  the  complicated  ones 
giving  usually  more  trouble  than  assistance.  Still,  there  are  circumstances 
in  which  a  timely  use  of  the  instruments  just  described  will  be  found  of 
great  assistance. 

II.— PREPARATION    OF    OBJECTS. 

It  is  designed  to  give  but  few  directions  for  the  preparation  of  objects  for 
the  microscope  in  this  place  :  particular  directions  in  manipulation,  for  those 
objects  requiring  an  especial  method  of  treatment,  will  follow  the  articles 
in  the  text. 

1.  Fluids. — Fluids,  such  as  blood,  urine,  &c,  require  but  little  prepara- 
tion :  a  small  portion  of  the  fluid  to  be  examined  is  placed  on  a  plain  glass 
slide  by  means  of  a  pipette,  and  is  then  covered  with  a  small  piece  of  thin 
glass.  This  latter  direction  should  be  always  followed,  otherwise  there  will 
be  the  two-fold  danger  of  soiling  the  object-glass,  if  a  high  one  be  used,  by 
inadvertantly  touching  the  fluid  under  examination,  and  also  of  allowing  the 

*  Quekett's  "Practical  Treatise." 


38  INTRODUCTION. 

vapour  of  the  fluid  to  condense  on  the  object-glass,  and  thereby  occasion  an 
indistinctness  of  vision  and  want  of  definition.  Care  must  be  taken  not  to 
place  too  great  a  quantity  of  the  fluid  on  the  slide  at  first;  one  small  drop  is 
usually  sufficient.  When  dilution  is  necessary — and  most  of  the  fluids, 
blood,  lymph,  &c,  are  better  examined  when  diluted — the  serum  of  the  blood 
or  albumen,  may  be  employed ;  in  most  cases,  water  cannot  be  employed 
on  account  of  its  reacting  properties. 

Fluids  generally  require  higher  powers  for  examination  than  solid  prep- 
arations. They  may  be  first  viewed  with  a  ith-inch  object-glass  and  then 
with  a  |th.  Any  of  the  reagents  may  be  introduced,  without  removing  the 
thin  glass,  by  means  of  a  pipette  containing  the  reagent  placed  at  one  edge, 
and  a  little  of  the  fluid  allowed  to  escape.  This  will  be  found  to  insinuate 
itself  under  the  glass  by  means  of  capillary  attraction,  and  the  effects  should 
be  observed  with  the  microscope. 

2.  Solids. — These  usually  require  more  care  in  their  preparation  for 
examination  than  fluids.  The  hard  solids,  as  bone,  require  to  be  cut  in  thin 
sections,  and  sometimes  polished  before  their  structure  can  be  discovered. 
Particular  directions  for  each  preparation  will  be  given  at  the  close  of  the 
chapters  treating  of  their  anatomy.  The  soft  solids  may  be  examined  either 
in  their  recent  condition  or  be  treated  by  various  chemical  agents,  or  be  far- 
ther  prepared  by  injection.  The  treatment  best  calculated  to  display  the 
structure  of  each  particular  tissue  will  hereafter  be  given. 

For  making  thin  sections  of  the  soft  solids,  the  Valentin's  knife  or  a  sharp 
scalpel  may  be  used.  The  compressor,  the  small  scalpels,  the  dissecting 
needles,  and  the  troughs  for  dissection  will  be  constantly  required. 

Objects  examined  in  this  condition  require  for  the  most  part  very  low 
powers.  If  the  compound  microscope  be  used,  a  one  or  two-inch  object- 
glass  will  be  power  high  enough.  In  many  cases,  the  simple  microscope 
will  be  most  efficient.  In  some  instances,  the  same  parts  of  the  object  require 
to  be  examined  with  successive  powers  as  high  as  the  ith-inch  object-glass. 
The  most  difficult,  as  well  as  the  most  beautiful  method  of  exhibiting  the 
structure  of  certain  tissues,  is  by  fine  injection. 

3.  Injections. — The  chief  objects  of  minute  injections  are  to  determine  the 
vascularity  of  a  tissue ;  the  relative  order,  size,  and  arrangement  of  arteries, 
veins,  and  often-times  lymphatics,  and  to  trace  the  final  distribution  of  the 
larger  blood-vessels  in  the  capillaries.  It  will  be  found  that  different  struct- 
ures will  present  different  arrangements  of  these  vessels,  always  coinciding 
with  the  differences  of  function. 

To  demonstrate  these  variations  of  structure,  it  is  necessary  that  the  injec- 
tion should  be  perfect  and  complete.     The  operation  is  a  delicate  one,  and 


OF     INJECTIONS.  39 

to  succeed  perfectly,  requires  some  practice ;  a  few  attempts,  however,  will 
convince  any  one  how  much  may  be  attained  by  perseverance.  Experi- 
ments may  first  be  made  in  comparative  anatomy,  and  the  different  organs 
of  sheep,  &c,  may  be  always  easily  obtained ;  and  these  not  only  afford 
beautiful  specimens  of  microscopic  anatomy,  but  for  the  most  part  are  as 
difficult  to  inject  as  the  same  organs  in  the  human  subject,  and  are  on 
that  account  very  good  practice. 

That  an  injection  may  succeed  well,  it  is  necessary,  that  some  time  should 
elapse  after  death  before  the  operation  be  attempted.  It  is  well  known  that 
immediately  after  death,  a  certain  contractility  of  the  vessels  takes  place, 
which  would  prevent  the  perfect  penetration  of  the  material  injected :  we 
must  therefore  wait  for  the  relaxation  of  this  contraction.  The  best  time 
for  injecting  is  in  summer,  about  twenty-four  to  thirty-six  hours  after  death, 
and  in  winter,  about  three  days.  These  are  general  directions,  which  may 
be  changed  according  to  the  especial  circumstances  of  the  case,  and  the  con- 
dition of  the  organ  to  be  injected.  It  would  be  a  still  greater  error  to  wait 
too  long  a  time ;  for  the  softened  vessels  would  certainly  be  ruptured,  and 
extravasation  of  the  injected  material  follow.  This,  if  extensive,  would  not 
only  spoil  the  beauty  of  the  preparation,  but  completely  defeat  the  object  of 
the  injection. 

A  serious  obstacle  to  perfect  injection  is  the  presence  of  coagulated  blood 
and  other  inatters  in  the  vessels,  more  especially  in  the  veins.  This  point 
has  not  been  sufficiently  regarded  in  minute  anatomy,  but  it  must  be  evident 
that  if  those  obstacles  which  irregularly  contract  the  calibre  of  the  vessels 
could  be  removed,  the  chance  of  success  would  be  much  greater.  A 
necessary  step  therefore,  preliminary  to  injection,  is  to  wash  out  the  blood- 
vessels; this  may  be  done  by  injecting  tepid  water  or  sulphuric  ether,  when 
this  latter  agent  enters  into  the  composition  of  the  injecting  material.  It  is 
also  of  great  advantage  to  place  the  body  or  organ  to  be  injected  in  a  warm  bath 
for  six  or  seven  hours  previous  to  the  operation.  The  temperature  should 
be  about  100°  to  106°  Fahrenheit.  For  small  organs,  when  removed  from 
the  body,  less  time  will  be  required. 

As  there  are  several  points  worthy  of  being  noted  in  the  injection  of  arte- 
ries and  of  veins,  the  two  orders  of  vessels  will  be  separately  noticed. 

Injection  of  Arteries. — As  a  general  rule,  the  complete  injection  of  the 
capillary  vessels,  by  means  of  the  arterial  trunks,  is  more  difficult  than  by 
the  veins,  for  the  reason  that  the  arteries  are  less  numerous  and  of  less  cal- 
ibre than  the  veins.  In  the  lungs,  this  disproportion  does  not  exist;  but  here, 
according  to  the  experience  of  Rossignol,  mentioned  at  the  end  of  the  article 
on  the  lungs,  the  best  injections  are  made  by  the  pulmonary  veins.  The 
arteries  have  the  advantage  of  requiring  less  preparation  than  the  veins,  and 


40  INTRODUCTION. 

of  being  always  ready;  they  are  also  more  empty  of  coagulated  blood,  and 
less  liable  to  rupture,  owing  to  the  greater  thickness  of  their  walls. 

Injections  by  the  arteries  should  be  made  not  by  the  aorta,  because  too 
many  vessels  would  be  divided  in  reaching  it,  but  by  the  large  arteries, 
which  are  accessible;  as  the  carotid,  brachial,  crural,  &c.  If  the  injection 
be  made  by  the  aorta,  the  visceral  trunks  should  be  first  ligatured. 

Injection  by  the  Veins. — On  the  other  hand,  the  veins  present  an  obstacle 
to  perfect  injection  in  their  numerous  valves ;  it  being  almost  impossible  to 
fill  the  vessels  by  one  operation,  owing  to  the  repellant  valvular  action. 
In  this  operation,  it  is  sometimes  necessary  to  inject  a  very  liquid  material 
first,  and  after  this  has  somewhat  set,  as  the  term  is,  then  to  inject  more  of 
the  same  material,  but  thicker.  The  proportions  for  these  divisions  are 
about  one-third  of  the  solid  material  to  be  injected  at  first,  and  the  remaining 
two-thirds  in  the  second  operation. 

Another  difficulty  in  injecting  by  the  veins  is  their  tendency  to  rupture; 
this  can  only  be  prevented  by  using  a  moderate  degree  of  force.  The 
existence  of  the  coagulated  blood  in  the  veins  has  been  already  alluded  to. 
Inferior  animals,  to  be  injected  by  the  veins,  should  be  bled  to  death,  and 
the  veins  by  which  the  injection  is  to  be  made,  opened.  The  veins  of  the 
extremities  are  usually  injected  by  the  superficial  lateral  internal  and  exter- 
nal trunks ;  when  the  chylo-poietic  viscera  are  to  be  injected  in  situ,  the 
vessels  are  to  be  filled  from  the  vena  portse  just  before  it  enters  the  trans- 
verse fissurb  of  the  liver. 

In  either  order  of  vessels,  the  opening  for  the  canula  of  the  syringe 
should  be  a  mere  slit  corresponding  to  the  long  diameter  of  the  vessel,  and 
not  transversely. 

A  young  and  lean  subject  will  be  found  the  best  for  perfect  injection, 
where  this  can  be  a  matter  of  choice. 

SYRINGE. 

The  first  minute  injections  were  made  by  Swammerdam,  who  taught  the 
art  to  his  friend  Ruysch,  (born  in  1638,  died  in  1731,)  and  who  improved 
upon  Swammerdam's  method. 

These  injections  led  to  many  discoveries,  and  propagated  many  errors. 
The  instrument  employed  by  Swammerdam  is  still  in  general  use  in  the 
medical  schools,  and  known  as  Swammerdam's  syringe. 

For  making  extensive  injections,  this  instrument  will  answer  every  purpose  ; 
for  injecting  small  organs  and  parts  of  the  extremities,  smaller  instruments 
must  be  employed.  Swammerdam's  syringe  consists  of  two  main  parts — 
the  syringe  proper  and  the  canula  or  pipe.  The  canula  is  fastened  in 
the  nozzle  of  the  syringe  by  means  of  a  bayonet-catch,  and  is  of  course 


SYRINGES.  41 

removeable  at  will.  A  modern  improvement  is  to  add  a  flexible  tube  to  the 
canula,  so  that,  in  the  operation  of  forcing  the  injection,  no  injury  will 
happen  to  the  vessel  in  which  the  canula  is  fixed,  and  no  derangement  of 
the  parts  of  the  subject  on  the  table.  The  canulas  are  of  different  sizes, 
to  correspond  with  the  calibres  of  the  vessels  into  which  they  are  to  be 
inserted. 

A  syringe  invented  by  Charriere,  of  Paris,  which  works  with  remarkable 
ease  and  exactness,  owing  to  the  arrangement  of  the  discs  of  leather  which 
form  the  piston,  is  advantageously  used  in  making  injections  with  smaller 
quantities;  with  this  syringe  also  are  canulas  of  different  sizes. 

These  syringes,  with  other  instruments  of  Charriere's  manufacture,  use- 
ful in  microscopic  manipulation,  may  be  purchased  at  Mr.  H.  Balliere's 
foreign  book-store,  No.  219  Fulton-street,  New  York.  Many  other  forms 
of  syringe  are  in  use,  and  all  have  their  advocates ;  but  in  general,  any 
form  in  which  the  working  of  the  piston  is  perfectly  true,  and  at  the  same 
time  easy,  will,  with  proper  care  and  attention  to  the  exclusion  of  air,  &c, 
answer  very  well.  The  writer  has  made  some  good  injections  of  small 
organs  with  the  ordinary  ear-syringe,  which  is  also  capable  of  having  can- 
ulas  of  different  sizes  attached  to  it.  Some  of  the  many  forms  of  patent 
syringes  sold  at  the  druggists  for  making  ordinary  enemata,  may  be  advan- 
tageously employed,  especially  when  the  material  of  the  injection  is  very 
fluid,  as  in  the  method  by  double-decomposition,  hereafter  to  be  noticed. 
These  instruments  would  all  require  certain  adjustments  in  the  arrange- 
ment of  canulas  which  the  student  could  himself  make.  One  form  of 
these  enema-syringes,  in  which  the  jet  is  continuous,  and  not  saltatim,  as  in 
the  forcing-pump,  is  the  best,  and  the  syringe  can  be  constantly  supplied 
with  the  injecting  material,  if  necessary,  by  an  assistant,  without  suspend- 
ing the  operation.  One  objection  to  this  instrument  is,  that  any  accident 
that  may  happen  during  the  operation,  such  as  rupture  of  a  vessel,  cannot 
be  appreciated  as  readily  as  when  the  piston  is  guided  by  the  hand.  In 
ordinary  injections,  as  already  stated,  the  part  to  be  injected  should  be 
placed  some  hours  in  warm  water,  before  the  operation  be  attempted.  The 
syringe,  canula,  and  injecting  material,  should  be  moderately  heated.  If 
the  injection  is  to  be  by  the  veins,  and  by  these  we  are  usually  more  suc- 
cessful than  by  arteries,  the  canula,  with  the  flexible  tube,  is  to  be 
secured  in  the  vessel  previously  incised  longitudinally,  and  the  canula 
secured  by  a  ligature:  a  second  ligature  should  lie  loose  upon  the  canula 
to  secure  the  vessel  when  the  operation  is  finished.  The  vein  may  then  be 
washed  out  by  an  injection  of  warm  water;  at  least  half  an  hour  should 
elapse,  to  allow  the  vessels  to  empty  themselves,  before  the  injection  be  pro- 
ceeded with.  As  it  is  important  to  exclude  all  air  in  the  operation,  the  tube 
and  canula  should  be  first  filled  with  the  fluid  material,  the  tube  be  tightly 


42  INTRODUCTION. 

corked,  and  the  canula  secured  in  the  vessel.  The  next  step  is  to  fill 
the  syringe,  and  secure  the  tube  by  the  bayonet-catch.  The  injection  may 
then  be  commenced,  with  a  force,  depending  somewhat  on  the  thickness  of 
the  material  employed ;  the  thinner  the  fluid,  the  less  force  will  be  neces- 
sary. When  it  is  recollected  how  slight  is  the  muscular  force  of  the  heart, 
it  will  be  easy  to  conceive  how  little  force  will  be  necessary  to  fill  the  ves- 
sels in  favourable  circumstances. 

When  a  rupture  of  a  large  vessel  occurs  during  the  injection,  and  this 
can  be  known  by  the  greater  ease  with  which  the  material  enters,  the  ope- 
ration must  be  suspended  and  the  vessel  secured.  If  the  vessel  itself  cannot 
be  isolated,  a  ligature  may  be  applied,  including  a  portion  of  the  tissue  sur- 
rounding it.  If  rupture  of  the  capillaries  takes  place,  the  operation  need 
not  be  suspended,  but  pressure  in  the  neighbourhood  of  the  suspected  rup- 
ture may  be  applied,  and  the  injection  must  be  continued  rather  longer  than 
when  no  such  accident  has  occurred. 

The  injection  being  finished,  time  must  be  allowed  for  it  to  set,  when  the 
dissection  may  be  commenced.  Many  patches  will  be  found  more  perfectly 
injected  than  others;  and  the  proportionate  success  can  only  be  known  by 
inspection  with  the  microscope. 

When  the  minutest  capillaries  are  not  injected,  the  preparation  may  still 
be  useful  in  displaying  the  second  order  of  vessels. 

Mucous  membranes  require  to  be  soaked  in  water  or  washed  with  a 
syringe,  to  free  them  from  epithelium  and  mucus. 

The  minute  dissection  of  injected  tissues  is  best  conducted  in  water,  by 
means  of  the  trough  and  dissecting  needles. 

In  conclusion,  it  may  be  observed  that  the  operation  of  minute  injection, 
when  properly  performed,  occupies  from  one  to  five  hours,  according  to  the 
size  of  the  specimen  and  the  quantity  of  material  required. 

No  haste  should  be  used,  for  unless  the  material  be  properly  prepared,  and 
the  vessels  carefully  filled,  one  may  be  certain  of  partial  or  complete  failure. 

MATERIALS. 
Many  substances  have  been  employed  as  the  bases  of  fine  injections,  but 
as  the  result  depends  more  on  the  medium  by  which  the  solid  part  of  the 
injection  is  conveyed  into  the  vessels,  the  most  useful  forms  will  be  here 
noticed  in  turn. 

1.  Injections  with  'Turpentine. — In  this  method,  materials  used  as  paints 
of  various  colours,  are  first  finely  ground  in  linseed  oil,  then  largely  diluted 
with  oil  of  turpentine.  The  paints  most  used  for  imparting  different  colours 
are :  Vermilion,  Chrome  Yellow,  Prussian  Blue,  White-lead.  In  making 
injections  with  these  paints,  too  much  importance  cannot  be  attached  to  their 


INJECTING      MATERIALS.  43 

being  ground  to  the  utmost  possible  fineness;  otherwise  the  colouring  parti- 
cles of  the  injection  cannot  penetrate  the  capillaries. 

These  paints,  already  finely  ground,  can  be  procured  at  the  stores  where 
"artist's  materials"  are  sold,  or  they  can  be  prepared  in  a  "paint-mill"  or 
on  a  house-painter's  slab. 

The  proportion  of  the  ground  paint  to  the  oil,  varies  with  the  intensity  of 
of  the  colour;  but  the  following  scale  will  usually  answer:  For  Vermilion, 
•jL-th  part  of  whole  mass  by  weight;  Prussian  Blue,  ^i^th;  Chrome  Yel- 
low, Tiu th  ;   White-lead,  yi ?th. 

If  it  be  found  that  the  proportion  of  blue  makes  the  injection  too  thin,  the 
blue  may  be  first  well  mixed  with  the  white-lead,  and  then  a  larger  propor- 
tion of  the  mixed  paint  employed.  When  too  much  blue  is  used,  the  colour 
produced  is  nearly  black,  and  therefore  too  strongly  absorbent  of  light. 

These  injections  require  to  be  but  slightly  warmed,  and  in  summer  this 
process  may  be  entirely  dispensed  with. 

When  injections  by  this  method  are  successful,  the  colours  soon  harden, 
and  are  well  preserved  for  a  long  time.  The  plan  is  the  only  one  recom- 
mended by  M.  Robin,  and  is  much  in  vogue  in  Europe. 

2.  Injections  with  Ether.— To  Dr.  P.  B.  Goddard,  of  Philadelphia,  is  due 
the  merit  of  having  first  employed  ether  in  minute  injections;  his  method  is 
described  by  him  in  the  Medical  Examiner  of  Philadelphia  for  December, 
1849,  and  is  here  quoted: 

"For  the  purpose  of  making  such  an  injection,  the  anatomist  must  provide  himself 
with  a  small  and  good  syringe;  some  vermilion,  very  finely  ground  in  oil;  a  glass- 
stoppered  bottle,  and  some  sulphuric  ether.  The  prepared  vermilion  paint  must  be 
put  into  the  ground-stoppered  bottle,  and  about  twenty  or  thirty  times  its  bulk  of 
sulphuric  ether  added;  the  stopper  must  then  be  put  in  its  place,  and  the  whole  well 
shaken.  This  forms  the  material  of  the  injection.  Let  the  anatomist  now  procure 
the  organ  to  be  injected,  (say  a  sheep's  kidney,  which  is  very  difficult  to  inject  in  any 
other  way,  and  forms  an  excellent  criterion  of  success,)  and  fix  his  pipe  in  the  artery, 
leaving  the  rem  open.  Having  given  his  material  a  good  shake,  let  him  pour  it  into 
a  cup,  and  fill  the  syringe.  Now  inject  with  a  slow,  gradual  and  moderate  pressure. 
At  first,  the  matter  will  return  by  the  vein  coloured,  but  in  a  few  moments  this  will 
cease,  and  nothing  will  appear  except  the  clear  ether,  which  will  distil  freely  from  the 
patulous  vein.  This  must  be  watched,  and  when  it  ceases,  the  injection  is  complete. 
The  kidney  is  now  to  be  placed  in  warm  water  of  120°  Fahrenheit,  for  a  quarter  of 
an  hour,  to  drive  off  the  ether,  when  it  may  be  sliced  and  dried,  or  preserved  in  alco- 
hol, Goadby's  solution,  or  any  other  anti-septic  fluid.  For  glands,  as  the  kidney, 
liver,  &c,  it  is  better  to  dry  and  mount  the  sections  in  Canada  balsam :  but  for 
membranous  preparations,  stomach,  intestine,  &c,  the  plan  of  mounting  in  a  cell, 
filled  with  an  anti-septic  solution,  is  preferable." 


44  INTRODUCTION. 

In  this  method,  as  in  the  preceding  one,  much  depends  on  the  fineness  of 
the  colour  used.  The  writer  has  examined  many  of  Dr.  Goddard's  injec- 
tions with  ether,  and  can  bear  witness  to  their  perfect  success. 

When  the  ether  injection  is  employed,  the  preliminary  steps  of  heating 
the  body  and  the  injection  must  of  course  be  dispensed  with.  If  the  veins 
are  to  be  injected,  they  should  be  washed  out  by  an  injection  of  pure  ether. 

3.  Injection  by  Double  Decomposition. — This  method  consists  in  taking 
advantage  of  the  known  power  of  certain  substances  to  decompose  each 
other,  and  form  an  insoluble  compound.  Upon  the  original  method  of  using 
these  materials,  Henry  Goadby,  Esq.  (late  dissector  of  Minute  Anatomy  to 
the  Royal  College  of  Surgeons,  London,)  has  made  some  important  improve- 
ments, an  account  of  which  he  first  published  in  the  London  Lancet,  and 
which  has  been  republished  in  the  Philadelphia  Examiner  for  March,  1850. 
Mr.  Goadby  thus  describes  the  original  process  and  his  own  experience: 

"M.  Gruby  has  published  an  account  in  the  Comptes  Rendus  of  some  very  successful 
injections  which  he  had  made  by  employing  certain  fluids,  which  he  used  separately, 
and  which,  when  they  met,  mutually  decomposed  each  other,  and  deposited  the 
colouring  matter  in  the  vessels  themselves. 

"He  used  saturated  solutions  of  the  chromate  or  bi-chromate  of  potash,  and  of  the 
acetate  of  lead:  he  directed  that  equal  quantities  of  these  fluids  should  be  used,  first 
injecting  all  the  chromate  of  potash,  to  the  extent  of  one-half  the  quantity  of  injec- 
tion supposed  to  be  necessary,  into  the  vessels,  and  subsequently  the  same  quantity 
of  the  acetate  of  lead. 

"As  soon  as  these  fluids  meet,  they  decompose  each  other;  the  acetic  acid  of  the 
acetate  of  lead  combining  with  the  potash  to  form  the  acetate  of  potash,  which  is  set 
free,  and  the  chromic  acid  of  the  chromate  of  potash  combining  with  the  lead  to  form 
the  beautiful  chromate  of  lead,  which  is  deposited  in  the  vessels. 

"  The  reports  which  had  reached  me  were  highly  confirmatory  of  M.  Gruby's  suc- 
cess with  these  fluids,  and  having  seen  Mr.  Bowman's  preparations  of  the  kidney 
injected  on  this  principle,  and  with  the  like  materials,  I  determined  to  employ  them. 
My  experiments,  however,  were  most  unsatisfactory;  for,  having  injected  a  terrier 
puppy,  a  dissection  of  several  hours  was  required  to  ascertain  whether  I  had  succeeded 
in  injecting  any  part  or  not,  and  my  best  reward  consisted  in  a  patch  of  capillaries, 
slightly  painted  of  a  pale  yellow  colour,  and  entirely  wanting  that  roundness  and  full- 
ness, characteristic  of  a  good  injection. 

"I  next  procured  a  human  foetus,  and  injected  it,  with  precisely  the  same  results. 

"On  making  inquiry  of  Mr.  Bowman,  touching  the  ordinary  success  which  had 
attended  his  experiments,  and  the  experiments  of  others,  so  far  as  he  knew,  he  told 
me  that  I  appeared  to  have  met  with  fair  average  results ;  for  that  the  labour  of  dis- 
secting, consequent  on  using  these  fluids,  was  always  great,  and  that  the  operator 
must  consider  himself  well  rewarded  for  two  or  three  days'  work,  by  finding  a  micro- 
scopic bit  well  injected. 

"From  this  narration  of  failures,  it  will  be  evident  that  the  fluids  rarely  meet  in  the 


INJECTING     MATERIALS.  45 

vessels,  otherwise  the  colour  would  be  necessarily  precipitated.  With  a  view  to  see 
exactly  what  took  place,  I  determined  to  inject  a  piece  of  intestine,  in  which  the 
whole  process  would  be  under  my  inspection.  I  placed  pipes  in  the  mesenteric  veins, 
and  secured  all  the  cut  vessels  in  the  usual  manner ;  I  then  proceeded  to  throw  in 
the  chromate  of  potash,  and  found  that  the  potash  would  not  wait  for  the  lead,  but 
came  out  instantly  through  the  parietes  of  the  vessels  as  fast  as  it  went  in,  and  in 
one  broad  stream  covered  the  table.  I  repeated  this  experiment  a  number  of  times, 
but  with  the  same  uniform  result;  on  some  occasions  I  threw  in  the  lead  also,  and 
as  the  vessels  were  moist  with  the  chromate,  the  slight  painting  I  have  mentioned 
took  place;  but  as  only  equal  quantities  of  the  two  fluids  produce  the  best  colour, 
the  excess  of  the  lead  was  useless. 

"Having  observed,  at  this  stage  of  my  experiments,  that  the  precipitated  chromate 
of  lead  is  remarkably  fine  and  soft,  I  determined  to  use  it,  in  lieu  of  vermilion,  with 
size;  and  although  the  success  was  far  greater  than  when  I  used  the  fluids  separately, 
the  results  were  in  no  way  superior  to  the  old  red  injection. 

"The  principle  involved  in  M.  Gruby's  use  of  these  fluids — that,  namely,  of  forming 
the  colour  within  the  vessels  themselves — appeared  to  be  undeniably  good,  notwith- 
standing it  had  so  signally  failed  in  my  hands,  and,  as  far  as  I  could  learn,  in  the 
hands  of  all  those  persons  who  had  hitherto  employed  it ;  and  I  had  no  doubt  that  if 
I  could  succeed  in  giving  some  consistence  to  the  fluids,  the  results  might  prove  more 
satisfactory.  For  this  purpose,  size  would  not  do,  as  it  is  rarely,  when  bought, 
much  too  strong  for  use,  and  it  would  not  bear  further  dilution.  I  therefore  pro- 
cured the  highly  concentrated  preparation  employed  by  pastry  cooks,  and  sold  by 
by  grocers,  under  the  name  of  gelatine.  The  following  is  my  formula  for  the  double 
injection  with  this  material: 

"Sat.  solution  of  bi-chromate  of  potash,  eight  fluid  ounces;  water,  eight  ounces; 
gelatine,  two  ounces. 

"Sat.  solution  of  acetate  of  lead,  eight  fluid  ounces;  water,  eight  ounces ;  gelatine, 
two  ounces. 

"Thus,  gelatine,  two  ounces,  are  dissolved  in  sixteen  ounces  of  fluid,  and  kept  and 
used  separately  as  before;  but  the  success  consequent  on  the  addition  of  the  gelatine 
was  quite  extraordinary;  the  vessels  were  all  full  and  round,  and  there  was  no 
extravasation;  and  for  reasons  hereafter  to  be  explained,  the  microscope  revealed 
scenes  so  rich  in  depth,  colour,  and  beauty,  as  to  exceed  the- best  red  injections  I 
have  ever  seen. 

"With  this  form  of  injection  I  have  never  failed;  I  have  injected  three  foetal  sub- 
jects so  minutely,  that  the  capillaries  of  the  skin,  and  of  every  tissue,  were  perfectly 
injected.  Among  the  best  specimens  I  obtained,  I  may  mention  injections  of  the 
papilla?  of  the  lips,  gums,  and  tongue;  of  the  pulps  and  capsules  of  the  teeth;  of  the 
conjunctiva  and  other  tissues  of  the  eye;  of  the  mucous  membrane  of  the  nose  and 
cellular  tissue;  fascia;  periosteum,  &c;  ceruminous  glands,  lymphatic  glands,  and 
thyroid  glands;  pericardium,  auricles  of  the  heart,  vasa  vasorum,  particularly  of  the 
aorta  and  vena  cava,  and  the  vessels  of  all  the  nerve  sheaths.  In  line,  one  foetus 
occupied  me  in  dissecting,  ten  hours  a  day,  for  two  months,  and  was  scarcely  half 
finished  at  the  expiration  of  the  time. 

"Having  described  the  success  attending  the  use  of  these  injecting  fluids,  I  must 


46  INTRODUCTION. 

new  say  how  they  are  to  be  mixed  and  used,  as  every  thing  depends  on  care  in  these 
respects. 

"Each  parcel  of  gelatine  must  be  dissolved  in  the  water  only,  (eight  ounces,)  and 
in  a  separate  water-bath.  The  water-baths  I  employ  consist  of  two  earthern  pans, 
such  as  are  applied  to  a  child's  chair,  and  capable  of  containing  about  one  quart  each; 
these  are  fitted  to  two  tin  kettles,  the  broad  flange  of  the  earthern  pan  resting  on  the 
rim  of  the  kettle,  the  pan  covered  with  a  common  saucepan-lid.  The  kettles  should 
be  furnished  with  a  bail  of  iron  wire,  like  that  of  a  glue-pot,  or  pitch-kettle. 

"The  gelatine  is  to  be  slowly  dissolved  in  the  eight  ounces  of  water;  when  this  is 
accomplished,  the  eight  fluid  ounces  of  bi-chromate  are  to  be  added  to  the  gelatine 
in  one  pan,  and  the  eight  fluid  ounces  of  acetate  of  lead  to  the  gelatine  in  the  other ; 
each  should  be  we'l  mixed  by  stirring  with  a  glass  rod,  a  separate  rod  being  used 
for  each  solution,  lest  the  chromate  of  lead  should  be  precipitated. 

"The  fluids  thus  prepared,  must  then  be  strained  through  fine  flannel  (using  a 
piece  for  each  fluid)  into  other  vessels,  the  earthen  pans  cleaned,  and  the  fluids 
returned  to  them.  The  injections  are  now  ready  for  use,  and  must  be  kept  at  a  tem- 
perature of  about  90°  by  the  warm  water  contained  in  the  kettles. 

"Directions  for  using  the  Injection. — The  best  subject  to  inject  is  a  foetus,  as  there 
are  no  cut  vessels  by  which  the  injection  can  escape.  A  pipe,  with  a  stop-cock 
attached,  should  be  firmly  tied  in  the  umbilical  vein,  leaving  the  arteries  open  until 
the  yellow  injection  makes  its  appearance,  when  they  should  be  secured.  It  is  most 
essential  that,  for  this  injection,  the  subject  be  warmed  through  by  immersion  in 
warm  water,  the  temperature  of  which  must  not  be  higher  than  90°,  or  corrugation 
of  the  tissues  will  take  place ;  it  will  require  from  one  hour  to  two  hours  to  accom- 
plish this,  and  the  temperature  must  be  maintained  until  the  injection  be  completed. 
The  whole  sixteen  ounces  of  the  potash  preparation  of  gelatine  must  now  be  used, 
care  being  taken  that  its  temperature  never  exceed  90°.  Some  manipulators  deem 
care  of  little  import  in  the  early  stage  of  injecting,  and  throw  in  the  first  few  syringe- 
fulls  rapidly,  and  only  exhibit  caution  when  the  subject  begins  to  fill.  In  my  expe- 
rience, this  is  an  error;  and  he  who  would  succeed,  must  be  equally  careful  and 
patient  throughout.  It  is  my  practice  to  let  the  piston  descend  so  slowly,  that  it  can 
scarcely  be  seen  to  move. 

"  Having  used  the  whole  of  the  first  preparation,  the  acetate  of  lead  must  be  used, 
when  the  colour  will  instantly  be  formed,  and  give  the  operator  some  idea  of  his 
progress. 

"The  temperature  of  the  subject  must  be  kept  up,  and  a  fresh  batch  of  injection 
made  and  strained  as  before.  In  about  half  an  hour  the  injection  may  be  resumed, 
and  the  bi-chromate  again  claims  precedence;  but  only  half  the  quantity  need  be  used 
now,  followed  by  an  equal  quantity  of  the  lead.  At  this  point  the  stop-cock  should 
be  turned,  and  the  subject  again  allowed  to  rest  for  half  an  hour;  the  remainder  of  the 
injections  may  then  be  used,  and  after  this,  in  all  probability,  the  subject  will  require 
another  batch.  The  manipulator  who  employs,  for  the  first  time,  as  much  injection 
for  a  foetus  as  I  have  already  directed  to  be  used,  and  who  experiences  the  great 
resistance  opposed  to  the  transmission  of  the  last  several  syringes-full,  especially  as 
the  body  will  by  this  time  be  swollen  and  tense  to  an  amazing  degree,  will  feel 
somewhat  surprised  to  learn,  that  if  he  suspend  the  operation  for  an  hour,  keeping 
up  the  temperature  in  the  meanwhile,  he  will  be  able  to  throw  into  the  subject  twenty 


INJECTING      MATERIALS.  47 

or  thirty  ounces  more  with  comparative  ease,  and  have  the  pleasure  of  seeing  many 
isolated  congeries  of  vessels  of  the  skin  gradually  approaching  each  other,  and  finally 
anastomosing  most  perfectly,  while  the  tension  of  the  body  will  be  so  great,  that  if 
the  piston  be  pressed  completely  down,  and  the  hand  withdrawn,  it  will  gradually  rise, 
and  the  same  may,  with  care,  be  repeated  several  times,  without  causing  extravasation. 

"Towards  the  conclusion  of  the  process,  the  injections  should  be  thrown  in  alter- 
nately ;  and  this  should  be  continued,  notwithstanding  the  prodigious  distortion  of  the 
body,  as  long  as  the  injection  is  felt  to  flow  in  the  vessels.  To  inject  a  foetus  well, 
on  this  plan,  will  occupy  from  four  to  five  hours.  The  operation  finished,  the  body 
should  be  thrown  into  cold  water,  and  should  not  be  dissected  until  the  next  day. 

"  The  Dissection, — Will  soon  reveal  what  has  become  of  the  injection,  and  is  alto- 
gether a  disagreeable  and  difficult  task.  It  will  be  found  that  nearly  all  the  gelatine 
and  acetate  of  potash  have  transuded  and  separated  the  tissues  widely  from  each 
other,  and  that  the  blood  has  been  diluted,  and  intimately  mixed  with  the  gelatine, 
which  is  coloured  by  it. 

"The  majority  of  preparations  thus  injected,  require  to  be  dried,  and  mounted  in 
Canada  balsam.  Each  preparation,  when  placed  on  a  slip  of  glass,  will  necessarily 
possess  more  or  less  of  the  coloured  infiltrated  gelatine,  which,  when  dry,  forms, 
together  with  the  different  shades  of  the  chromate  of  lead,  beautiful  objects,  possessing 
depth  and  richness  of  colour.  The  gelatine  also  separates  and  defines  the  different 
layers  of  vessels.  By  this  injection,  the  arteries  are  always  readily  distinguishable,  by 
the  purity  and  brightness  of  the  chromate  of  lead  within  them,  while  the  veins  are 
detected  by  the  altered  colour  imparted  by  the  blood. 

"Those  preparations  which  require  to  be  kept  wet,  can  be  preserved  perfectly  in 
my  B-fluid,  specific  gravity  1,100;  the  A-fluid  destroys  them. 

"The  bi-chromate  of  potash  is  greatly  superior  in  colour  to  the  chromate,  which 
yields  too  pale  a  yellow;  and  subsequent  experience  has  convinced  me  that  the  ace- 
tate of  potash  frequently  effects  its  liberation  by  destruction  of  the  capillaries,  and 
this,  even  long  after  the  preparations  have  been  mounted  in  Canada  balsam ;  perhaps 
this  may  be  owing  to  some  chemical  action  of  the  acetate  of  potash  upon  them. 

"Although  highly  desirable,  as  the  demonstrator  of  the  capillaries  of 'normal  tissues, 
I  do  not  think  this  kind  of  injection  fitted  for  morbid  preparations,  the  infiltrated 
gelatine  producing  appearances  of  a  puzzling  kind,  and  calculated  to  mislead  the 
pathologist. 

"In  preparing  portions  of  dried,  well-injected  skin  for  examination  by  the  micro- 
scope, I  have  tried  the  effect  of  dilute  nitric  acid,  as  a  corroder,  with  very  good  results. 
But  probably,  liquor  potassse  would  have  answered  this  purpose  better." 

The  writer  has  inspected  many  beautiful  injections  in  the  possession  of 
Dr.  Goadby,  by  his  chemico-gelatinous  method,  and  can  confirm  the  fore- 
going account  of  his  success  and  the  excellence  of  his  method. 

Dr.  Goadby,  in  the  article  referred  to,  recommended  that  the  nitrate  of 
lead  be  substituted  for  the  acetate  ;  on  experiment,  however,  this  change  has 
not  been  found  to  answer,  as  the  colour  after  mounting  has  been  observed 
to  fade. 

Other  colours  may  also  be  obtained  by  the  method  of  double  decompo- 


48  INTRODUCTION. 

sition ;  thus,  a  red  precipitate,  by  the  iodide  of  potassium  and  the  bi-chloride 
of  mercury ;  blue,  by  the  ferro-cyanide  of  potassium  and  the  peroxide  of 
iron,  &c. 

Most  of  the  preceding  remarks  apply — 1st,  to  cases  in  which  the  whole  or 
large  part  of  the  subject  is  to  be  injected ;  and,  2d,  to  cases  in  which  both 
arteries  and  veins  are  to  be  injected  by  one  material. 

The  perfect  injection  of  only  one  set  of  vessels  or  the  two  sets  by  differ- 
ent  materials,  so  as  to  fill  the  capillaries,  and  yet  not  exceed  each  one's 
proper  limits,  is  one  of  the  most  difficult  operations  in  minute  anatomy :  it 
is  comparatively  easy  to  fill  both  orders  of  vessels  by  one  injection. 

With  regard  to  the  amount  of  force,  and  quantity  of  fluid  necessary  for 
the  injection  of  only  one  set  of  vessels,  no  directions  can  be  given  that 
would  not  require  modification  according  to  each  particular  case ;  and  suc- 
cess must  depend  more  on  repeated  trials  than  upon  any  rules. 

In  cases  where  two  or  more  materials  are  to  be  injected,  the  arteries,  on 
account  of  their  lesser  volume,  should  be  first  filled.  The  colours  may  be 
used  in  the  following  order:  Arteries,  blue;  Veins,  yellow. 

When  red  and  yellow  are  used,  the  two  colours  meeting  in  the  capillaries, 
form  an  orange  tint,  making  it  difficult  to  recognise  each  proper  colour. 

When  the  liver  is  to  be  injected,  its  four  orders  of  vessels  may  be  thus 
filled :  Arteries,  blue ;  Vena  Portse,  yellow ;  Hepatic  vein,  red ;  Hepatic 
duct,  white. 

When  the  uriniferous  tubes  are  to  be  filled,  they  may  be  injected  with  white. 

A  few  other  materials  for  fine  injections  may  be  here  noticed,  although 
the  best  have  been  already  given : 

Pure  Gelatine. — In  using  this  material,  Tulk  and  Henfrey  direct  that 
seven  parts  in  winter  and  twelve  parts  in  summer  of  dried  gelatine  be  dis- 
solved to  the  consistence  of  jelly  in  one  hundred'  parts  of  water.  The  jelly 
is  then  to  be  made  liquid,  as  flowing  as  water,  by  gentle  heat,  and  the 
colouring  matter  added.  The  colouring  particles  must  be  suspended  in 
water :  a  red  colour  may  be  produced  by  vermilion  or  carmine ;  blue,  by 
indigo  or  Prussian  blue ;  yellow,  by  gamboge,  &c. 

After  the  injection  has  been  strained  through  a  fine  cloth,  it  is  ready  for 
use,  and  must  be  thrown  in  while  warm.  This  gelatine  is  the  same 
employed  by  Dr.  Goad  by  in  his  method  by  double  decomposition,  and  ma)r 
be  procured  at  the  druggist's  or  grocery  stores. 

Fresh  milk,  used  before  the  cream  has  commenced  to  form,  and  coloured 
by  a  watery  suspension  of  the  finest  particles  of  indigo,  carmine,  &c,  may 
also  be  used.  When  the  injection  is  completed,  the  preparation  must  be 
deposited  in  acetic  acid,  or  dilute  hydro-chloric  acid,  for  twelve  hours  to 
coagulate  the  milk. 


PRESERVATION     OF     OBJECTS.  49 

This  form  of  injection  is  said  to  be  well  adapted  for  organs  that  have  been 
preserved  for  any  time  in  weak  alcohol.  In  this  fluid,  the  vessels  become 
so  contracted,  that  any  thing  like  minute  injection  is  very  uncertain. 

The  ingredients  employed  by  Berres  and  Hyrtl,  of  Vienna,  whose 
injections  have  become  so  famous,  are  finely  levigated  cinnabar,  copal  var- 
nish, and  gum  mastich.  For  a  full  account  of  Berres'  method,  see  his 
"  Microscopic  Anatomy,"  fob,  published  at  Vienna,  in  Dutch  and  Latin,  1837. 

In  conclusion,  the  writer  would  state  that,  from  personal  experience  and 
observation,  any  of  the  foregoing  methods  may  prove  perfectly  efficient  and 
satisfactory,  if  proper  time  be  allowed  to  make  the  injection,  due  attention 
paid  to  the  preliminaries,  and  sufficient  perseverance  exercised  to  obtain 
any  useful  experience. 

The  anatomist  will  therefore  find  it  to  his  interest  to  persevere  in  any 
particular  form  of  injection  he  may  select,  rather  than  make  occasional 
trials  with  different  materials. 

In  addition  to  these  requisites,  success,  in  any  given  case,  will  be  found 
to  depend  much  on  the  peculiar  condition  of  the  vessels,  a  certain  willing- 
ness on  their  part  (if  it  may  be  so  expressed)  to  be  injected.  This  condition 
will  be  more  generally  found  in  animals  that  have  been  bled  to  death. 


III.— PRESERVATION    OF    OBJECTS. 

To  properly  preserve  objects  that  have  cost  much  time  and  labour  to  pre- 
pare, will  be  at  once  acknowledged  a  most  important  part  of  microscopical 
manipulation.  The  different  cements  useful  to  the  microscopist  will  be 
first  described.  Not  to  embarrass  the  beginner  with  too  long  a  list,  the 
most  useful  only  are  given. 

CEMENTS. 

1.  Jaf  annex's  Gold-size.  —  This  mixture  may  be  obtained  at  almost  all  the 
varnish  stores,  and  consists  of  boiled  linseed  oil,  dry  red-lead,  litharge,  cop- 
peras, gum-animi,  and  turpentine.  Its  cost  is  trifling,  but  it  needs  to  be 
about  three  years  old  before  it  will  dry  rapidly.  It  should  have  the  consist- 
ence of  thick  syrup,  so  as  not  to  run  too  much  when  applied.  If  the  gold- 
size  be  too  thin,  it  may  be  thickened  by  being  rubbed  up  with  a  little  lamp- 
black or  litharge.  This  cement  is  the  most  useful  of  all  for  fastening  the 
covers  of  cells,  and  may  also  be  employed  for  cementing  the  cells  them- 
selves to  the  glass  slides. 

2.  Asphaltum  Cement.  —  This  is  made  by  dissolving  asphaltum  in  boiling 
linseed  oil  or  turpentine,  and  is  of  fine  jet-black  colour.  It  may  be  used  for 
cementing  cells  to  slides,  or  cementing  down  the  covers  of  the  cells.     It  is 

4 


50  INTRODUCTION. 

not  acted  on  by  weak  alcoholic  solutions,  and  may  therefore  be  used  when 
alcohol  is  employed  as  the  mounting  fluid  :  as  a  cement  for  the  covers  of 
cells,  it  is  by  no  means  equal  to  the  gold -size. 

3.  Sealing-wax  Cement.  —  This  is  prepared  by  dissolving  a  quantity  of 
any  coloured  sealing-wax  in  alcohol,  sufficient  to  produce  a  cement  of  the 
consistence  of  thick  syrup.  Its  uses  are  the  same  as  the  two  preceding 
cements,  but  inferior  to  both. 

4.  Canada  Balsam,  dissolved  in  ether  or  turpentine,  and  evaporated  to  a 
consistence  sufficient  to  allow  its  being  laid  on  with  a  camel's-hair  brush, 
has  been  recommended  as  a  cement  for  fastening  cells  to  the  glass  slides. 
Tt  needs,  however,  the  addition  of  a  little  heat,  to  render  it  sufficiently  fluid 
to  make  the  union  firm,  and  free  from  air  bubbles.  This  heat  may  be 
applied  by  means,  of  a  spirit-lamp  to  the  under  side  of  the  glass  slide,  after 
the  balsam  has  been  put  on,  and  the  cell  placed  in  the  desired  position. 
When  the  balsam  becomes  fluid,  the  cell  may  be  pressed  down,  and  the  air 
bubbles  will  escape.     This  cement  is  apt  to  become  brittle  by  age. 

5.  Marine  Glue.  —  This  substance  is  in  most  use  abroad  for  cementing 
cells  to  glass  slides,  and  is  composed  of  gum-shellac,  caoutchouc,  and  naptha. 
The  kind  best  adapted  for  microscopic  purposes,  is  that  known  in  commerce, 
as  G.  K.  4,  and  may  be  procured  from  Messrs.  Pike  and  Sons,  opticians, 
of  New  York,  at  a  small  expense. 

The  directions  given  by  Mr.  Quekett,  and  others,  for  its  use,  involve  a 
long  and  tedious  process,  and  are  here  omitted.  A  method  equally  good, 
and  consuming  much  less  time,  has  been  adopted  by  the  writer,  and  is  in 
every  way  satisfactory :  A  small  tin  cup,  with  a  cover,  is  used,  capable  of 
holding  about  six  ounces ;  into  this  is  poured  about  two  ounces  of  Canada 
balsam,  and  about  the  same  quantity  in  bulk  of  the  marine  glue,  cut  in 
shavings.  These  are  placed  over  a  spirit-lamp,  or  in  a  sand  bath,  and  stir- 
red occasionally,  until  they  begin  to  boil,  when  the  cement  is  ready  for  use. 
It  is  then  applied  with  a  brush  to  the  under  side  of  the  cell  to  be  cemented 
on,  and  pressed  on  the  glass  slide,  previously  warmed.  By  this  method, 
twenty-five  or  thirty  cells  may  be  cemented  in  a  very  few  minutes,  and  the 
cement  may  be  put  aside,  and  will  be  again  ready  for  use  on  being  heated 
to  fluidity. 

6.  Compound  Cement.  —  This  mixture,  which  the  writer  has  found  the 
most  useful  and  least  troublesome  of  all  cements,  is  made — first,  of  gum-shel- 
lac dissolved  in  naptha,  and  of  the  consistence  of  syrup;  this  cement — as 
it  dries  very  quickly  and  is  quite  hard  and  firm — would  be  very  useful  by 


PRESERVATION      OF      OBJECTS.  51 

itself,  were  it  not  for  its  brittleness;  this  is  obviated  by  mixing  it  with  equal 
parts  of  thick  gold-size.  This  cement,  which  must  be  kept  in  a  stoppered 
bottle,  is  always  ready  for  use,  and  may  be  applied  without  heat,  by  means 
of  a  camel's-hair  pencil,  to  the  under  side  of  the  glass  cell.  This  is  pressed 
firmly  on  the  glass  slide,  and  the  superfluous  cement  may  be  scraped  off, 
when  hardened.  This  cement  dries  rapidly,  is  not  brittle,  is  not  acted  on 
by  any  of  the  fluids  commonly  used  for  mounting  objects,  and  has  the  great 
advantage  of  being  always  ready.  It  may  also  be  used  for  fastening  the 
covers  of  cells  where  a  thick  cement  is  needed.  But  for  this  purpose  noth- 
ing can  be  better  than  the  gold-size,  three  or  four  years  old. 

7.  Gum- Arabic  Cement.  —  A  very  strong  cement  may  be  made  by  dis- 
solving three  parts  gum-arabic  and  one  part  of  fine  sugar  in  distilled 
vinegar. 

The  cement  sold  in  the  shops  as  the  diamond  cement,  which  depends  for 
its  adhesiveness  on  the  isinglass  contained  in  it,  and  also  the  liquid  glue, 
which  contains  a  large  portion  of  gum-shellac,  may  be  made  use  of  as 
occasion  requires.  The  best  cements,  however,  are  the  first,  fifth,  and  sixth 
of  those  already  mentioned. 

Glass  Slides  and  Cells  for  preserving  Objects.  —  The  glass  slide,  so  useful 
in  microscopic  examinations,  and  so  necessary  in  the  preservation  of  objects, 
is  a  plain  slip  of  thin  plate  or  flattened  crown-glass,  three  inches  long  and 
one  inch  wide.  The  size  is  of  course  arbitrary,  but  the  one  mentioned  is 
that  recommended  by  the  London  Microscopic  Society,  and  is  in  general 
use  by  English  and  American  microscopists  :  it  is  therefore  desirable  that  in 
exchanges  and  purchases,  a  uniformity  of  size  should  exist.  The  plate  or 
crown-glass  is  purchased  in  sheets;  the  former  being  much  the  best,  but 
most  expensive,  and  is  first  cut  with  a  glazier's  diamond  in  slips  three 
inches  wide;  these  are  again  cut  in  slips  one  inch  in  width,  which  gives 
the  necessary  size:  the  rough  edges  are  made  smooth  by  rubbing  them  on 
a  cast-iron  plate,  with  emery-powder  wet  with  water.  It  is  much  better, 
however,  to  have  this  done  at  a  lapidary's  or  glass-cutter's;  Mr.  Isaac  Tay- 
lor, glass-cutter,  corner  of  Hester  and  Elizabeth  streets,  New  York,  will 
smooth  any  number  of  slides  at  the  rate  of  fifty  cents  per  one  hundred. 

Thin  Glass.  —  The  thin  glass  used  for  covering  certain  objects,  fluids,  &c, 
while  under  examination  with  the  microscope,  and  for  forming  the  covers  of 
cells  that  are  destined  to  preserve  objects,  is  manufactured  by  Messrs. 
Chance  and  Company,  of  Birmingham,  solely  for  this  purpose.  It  is  of  two 
varieties  of  thickness,  and  known  as  thick  and  thin  glass :  in  each  case  it  is 
sold  by  the  ounce,  the  thin  glass  costing  about  twice  as  much  as  the  other, 


52 


INTRODUCTION 


but  of  course  containing  more  in  surface.  Messrs.  Chance  and  Company 
have  a  branch  of  their  house  in  New  York,  at  No.  42  Cliff-street,  and  are  so 
obliging  as  to  sell  any  quantity,  however  small,  at  much  more  moderate 
rates  than  were  formerly  demanded  by  opticians  and  others,  who  imported 
it  themselves.  The  plate  and  crown-glass  for  slides  may  also  be  procured 
at  the  same  house. 

For  use,  the  thin  glass  is  cut  in  squares,  about  three-quarters  of  an  inch 
in  size,  or  in  circles,  a  little  less  in  size  than  the  outer  circumference  of  the 
cell  to  be  covered.  In  either  case,  the  cutting  is  performed  by  a  writing 
diamond,  the  glazier's  diamond  being  too  heavy.  To  cut  the  thin  glass  in 
squares  is  very  easy,  care  being  taken  that  the  sheet  of  glass  to  be  cut  is 
made  to  lie  flat  on  a  hard  smooth  table,  or,  still  better,  on  a  sheet  of  plate 
glass  slightly  wet.  To  cut  circular  covers  from  thin  glass,  is  rather  more 
difficult :  it  may  be  done  by  taking  a  thin  section  of  glass  tube,  or  a  circular 
piece  of  stout  gutta-percha,  of  the  size  desired  for  the  covers,  and  laying 
it  on  the  thin  glass  (this  having  been  previously  cut  in  strips),  and  then  pass- 
ing the  diamond  either  inside  or  outside  of  the  circle,  according  to  the  size 
desired. 

For  those  who  prefer  this  method  of  cutting  circular  covers,  a  most  useful 
instrument  has  been  devised  by  Mr.  Wm.  E.  Johnson,  of  Utica,  consisting 
of  a  stout  piece  of  German  silver  or  other  hard  metal,  about  eight  inches 
long,  one  and  a  half  wide,  and  one-eighth  of  an  inch  thick.  In  this  plate 
are  drilled  circles  of  different  sizes,  from  T9g  to  |f  of  an  inch  in  diameter. 
The  circular  covers  of  thin  glass  can,  by  aid  of  this  instrument,  be  cut  of 
any  required  size,  and  the  weight  of  the  metal  makes  the  instrument  less 
liable  to  slip,  than  when  a  section  of  tube  or  gutta-percha  is  used.  The 
form  of  the  instrument  is  represented  at  Fig.  6 : 


To  cut  glass  satisfactorily  by  this  method,  it  is  necessary  to  use  a  dia- 
mond having  a  true  point,  or  one  that  will  cut  in  any  direction.  Most  of 
the  writing  diamonds  sold,  will  cut  but  in  one  direction. 

Mr.  Quekett  has  described  an  instrument  devised  for  the  purpose  of  cut- 
ting thin  circular  covers.  A  much  simpler  instrument,  however,  is  repre- 
sented in  Fig.  7 : 


PRESERVATION      OF      OBJECTS. 


53 


Fig.  7. 

It  usually  forms  one  of  the  instruments  furnished  in  a  mathematical  instru- 
ment case,  and  can  be  readily  procured  at  any  store  where  such  instruments 
are  sold  :  It  consists  of  two  arms  united  by  a  cradle  joint ;  one  arm  pointed, 
like  the  arm  of  a  pair  of  ordinary  dividers.  The  other  arm  is  about  one- 
half  the  length,  having  a  circular  opening,  divided  perpendicularly  in  the 
centre.  The  two  sides  of  this  circle  are  made  to  approach  and  separate  by 
means  of  a  small  adjusting-screw.  The  original  design  of  the  instrument, 
is  to  draw  circles  on  paper,  by  means  of  a  lead  pencil  fastened  in  the  circu- 
lar opening  by  the  screw.  In  cutting  glass,  the  writing  diamond  is  substi- 
tuted for  the  lead  pencil,  and  after  the  cutting-point  of  the  diamond  is  turned 
in  the  proper  direction,  the  diamond-holder  is  to  be  secured  at  the  proper 
distance  by  means  of  the  screw:  as  the  steel  arm  of  the  instrument  usually 
terminates  in  a  sharp  point,  this  must  be  removed,  and  a  blunt  point  made. 
This  may  rest  on  a  small  circle  of  flat  lead  or  box-wood,  or  gutta-percha. 
If  it  be  found  this  rest  is  disposed  to  slip,  a  piece  of  chamois  leather  may 
be  pasted  on  the  under  side  of  the  rest ;  if  necessary,  this  may  be  moist- 
ened with  a  little  water  or  a  thin  mucilage  of  gum-arabic. 

The  instrument  having  been  adjusted  so  as  to  cut  a  circle  of  the  required 
size,  is  firmly  held  upon  the  thin  glass,  this  having  previously  been  cut  in 
slips  a  little  larger  than  the  required  circles,  and  made  to  describe  a  circle 


54  INTRODUCTION. 

in  the  same  manner  as  if  the  lead  pencil  and  paper  were  used.  Sometimes 
it  will  be  found  better  to  turn  the  slip  of  glass  round,  holding  the  diamond 
stationary.  The  pressure  must  be  light,  but  steady,  and  the  edges  outside 
the  circle  are  easily  removed.       , 

Glass  Cells.  —  For  the  preservation  of  injected  preparations  and  other 
thick  animal  structures,  some  kind  of  cell  is  necessary  in  which  to  deposit 
the  object.  This  cell  may  be  made  of  glass,  of  gutta-percha,  or  some  thick 
cement,  painted  on  the  slide  in  the  desired  shape,  and  allowed  to  harden. 
Those  of  glass  are  the  best,  and  are  of  different  kinds. 

1.  The  Thin-glass  Cell.  —  This  cell,  useful  in  mounting  thin  and  delicate 
structures,  is  made  by  taking  a  square  inch  of  the  thicker  kind  of  thin  glass, 
and  drilling  a  hole  in  it  of  about  half  an  inch  in  diameter.  The  glass  so 
drilled  is  then  to  be  cemented  to  a  plain  glass  slide,  by  means  of  the  marine 
glue,  or  the  compound  cement,  in  the  manner  already  described.  When  the 
cement  becomes  dry  and  hard,  the  cell,  after  being  properly  cleaned,  which 
may  be  done  by  scraping  off  the  harder  portions  of  the  cement  with  a  knife, 
and  then  washing  the  cell  with  a  solution  of  borax,  or  some  sulphuric  ether,  is 
ready  for  use. 

2.  The  Drilled  Cell,  is  made  in  the  same  way,  but  in  this  form,  plate-glass 
of  any  desired  thickness  may  be  employed,  according  to  the  thickness  of  the 
object  to  be  mounted.  Hence,  if  this  form  of  cell  be  used,  it  will  be  neces- 
sary to  have  them  of  different  degrees  of  thickness,  as  well  as  of  different 
sized  calibres.  They  are  to  be  cemented  to  the  glass  slides  in  the  same 
manner  as  thin  glass  cells.  When  these  cells  are  well  made,  they  are  the 
best  in  use;  but,  as  will  readily  be  seen,  it  is  a  difficult  matter  to  drill  the 
holes  without  fracturing  the  glass. 

3.  Tube  Cells.  —  These  are  sections  of  stout  glass  tube,  of  different  cali- 
bres, from  ith  to  |ths  of  an  inch,  cut  of  any  desired  thickness,  and  cemented 
to  the  glass  slide  in  the  same  manner.  These  sections  are  readily  made  by 
means  of  a  lapidary's  wheel,  charged  with  diamond-dust;  afterwards  the 
cut  surfaces  must  be  ground  perfectly  flat,  but  not  polished.  These  cells 
are  exceedingly  neat  in  appearance,  and  can  be  obtained  at  much  less  cost 
than  the  drilled  cells.  Mr.  Mason,  lapidary,  No.  156  Fulton-street,  has 
made  many  of  these  cells  for  different  microscopists  in  this  city,  and  at  much 
less  price  than  it  would  cost  to  import  them.  Where  only  one  size  can  be 
obtained,  a  cell  of  about  f  ths  of  an  inch  in  calibre,  and  ith  of  an  inch  in  thick- 
ness and  height  when  cemented,  will  be  more  generally  useful  than  any 


PRESERVATION      OF      OBJECTS.  55 

other  one  size.     It  is  better  to  have  them  of  different  sizes,  where  this  is 
possible. 

4.  Built-up  Cells.  —  When  neither  of  the  preceding  forms  of  cells  can  be 
obtained,  the  built-up  cells  will  be  found  a  good  substitute,  and  can  be  easily 
made  by  the  student  himself.  These  consist  of  four  pieces  of  glass  of  proper 
thickness  and  width,  cemented  to  a  glass  slide,  so  as  to  form  an  oblong  or 
square  cell.  Take,  for  instance,  a  piece  of  plate-glass,  |th  of  an  inch  in  thick- 
ness, one  inch  in  length,  and  f  ths  of  an  inch  in  breadth  ;  then  with  a  glazier's 
diamond  and  rule,  cut  off  strips  from  each  side,  ith  of  an  inch  in  width,  and 
cement  these  to  the  plain  glass  slide,  in  the  precise  order  in  which  they 
were  cut  off.  This  latter  step  in  the  process  may  be  insured  by  marking 
the  different  corners  with  ink  or  the  point  of  a  diamond.  These  cells  may 
be  made  of  any  size  and  thickness,  and  in  these,  as  well  as  in  the  other 
forms  of  cells,  the  marine  glue  or  the  compound  cement  may  be  used. 

5.  Gutfa-Percha  Cells.  —  Another  very  serviceable  kind  of  cell,  which 
may  be  employed  when  the  drilled  or  tube  cells  cannot  be  obtained,  is  made 
from  gutta-percha.  Dr.  Goddard,  of  Philadelphia,  was  the  first  to  adopt  this 
form,  which  is  readily  made  in  the  following  manner  :  Take  a  flat  piece  of 
gutta-percha  of  about  |th  of  an  inch  in  thickness,  and  with  a  saddler's-punch, 
f  ths  of  an  inch  in  diameter,  cut  several  circles  from  the  gutta-percha :  then 
with  a  punch  one  size  smaller,  or  about  fths  of  an  inch  in  diameter,  cut  from 
these  circles  a  centre  piece.  This  is  to  be  thrown  aside,  and  there  remains  a 
cell,  resembling  a  glass  tube  cell,  ith  of  an  inch  in  depth,  and  with  the  sides 
-i-th  of  an  inch  thick :  this  is  then  cemented  with  the  marine  glue  and  Canada 
balsam  to  the  plain  glass  slide,  in  the  same  manner  as  the  other  forms. 
Other  cells  may  be  made  of  white  lead,  melted  marine  glue,  or  gold-size 
thickened  with  lamp-black.  These  substances  are  all  to  be  traced  on  the 
glass  slide  when  in  a  fluid  state,  so  as  to  form  the  necessary  sized  cells,  and 
allowed  to  harden  before  fit  for  use.  The  superfluous  material  may  be  cut 
away  before  mounting  the  object. 

Gutta-percha  dissolved  in  chloroform,  on  account  of  its  quickly-drying 
properties,  has  been  recommended  for  this  variety  of  cell.  The  writer  has 
used  it,  but  does  not  find  it  possesses  any  advantages  over  the  other  substances 
already  named,  and  indeed  is  not  equal  to  the  cell  made  with  gold-size  and 
lamp-black. 

In  constructing  cells  of  either  of  these  materials,  it  has  always  been  found 
difficult  to  draw  the  cell  so  true  in  form,  as  to  have  a  neat  appearance.  The 
writer  has  adopted  a  method  by  which  circular  cells  may  always  be 
described  exactly  true,  and  made  of  any  desired  depth.     For  this  purpose, 


56  INTRODUCTION. 

the  little  instrument  with  the  writing  diamond  used  in  cutting  circles  of  thin 
glass,  is  employed. 

In  the  present  operation,  a  camel's-hair  pencil,  fine  or  coarse,  according 
to  the  desired  thickness  of  the  cell,  is  substituted  for  the  writing  diamond : 
the  pencil,  having  been  dipped  either  in  the  asphaltum,  gold-size,  or  any- 
other  cement,  is  made  to  describe  a  circle  in  the  same  manner  as  the  dia- 
mond in  cutting  the  thin  glass.  Smaller  cells,  constructed  in  this  way,  will 
be  found  very  useful  in  mounting  minute  portions  of  muscular  fibre  and 
other  delicate  structures  that  require  to  be  viewed  with  high  powers. 

FLUIDS  FOE  MOUNTING  OBJECTS, 

These  require  to  be  varied  according  to  the  nature  of  the  structure  to  be 
mounted :  among  many  that  may  be  used  for  this  purpose,  the  following  are 
the  most  useful : 

It  may  be  here  remarked  that  all  the  fluids  that  may  be  employed  in 
mounting  objects,  should  be  prepared  sometime  before  required  for  use; 
otherwise  many  of  them  will  be  found  to  contain  an  infinite  number  of  air- 
bubbles,  which  will  require  the  object  to  be  remounted  before  it  can  be 
studied  with  the  microscope. 

1.  Alcohol  and  Water.  —  As  in  the  preservation  of  large  specimens  of 
general  anatomy,  alcohol  and  water  is  more  generally  useful  than  any 
other  fluid,  so  by  the  microscopist,  this  mixture  is  more  to  be  relied  on  than 
any  other.  The  proportions  used  in  ordinary  preparations  (equal  parts  of 
water  and  alcohol)  will  be  found  too  strong  for  most  of  the  cements  used  in 
microscopic  manipulation ;  and  it  has  been  ascertained  that  a  weaker  solu- 
tion than  the  above  will  answer  perfectly  well  as  a  preservative,  and  not  act 
on  the  cement.  The  proportion  best  adapted  for  this  purpose,  is  one  part 
alcohol,  about  60°  above  proof,  to  five  of  distilled  water :  with  this  fluid, 
the  gold-size,  or  asphaltum,  may  be  safely  used  in  cementing  down  the 
covers  of  cells. 

2.  Goadoy's  Solution.  —  The  following  formulse  are  those  in  use  by  Dr. 
Goadby,  for  the  second  of  which  he  was  rewarded  by  the  "  Society  of  Arts," 
with  a  gold  medal. 

A-l  Solution.  —  Rock  salt,  4  ounces;  alum,  2  ounces;  corrosive  subli- 
mate, 2  grains ;  water,  1  quart.     Mix.     Very  astringent. 

A-2  Solution.  —  Rock  salt,  4  ounces;  alum,  2  ounces;  corrosive  subli- 
mate, 4  grains ;  water,  2  quarts.  Mix.  Generally  useful,  except  where 
the  carbonate  of  lime  is  present. 

B  Solution.  —  Rock  salt,  8  ounces ;  corrosive  sublimate,  2  grains ;  water, 


FLUIDS      FOR      MOUNTING      OBJECTS.  57 

1  quart.     Mix.     Specific  gravity,  1.100. — Two  ounces  of  salt  in  addition 
to  each  quart  of  water  will  make  the  specific  gravity  1.148. 

This  solution  preserves  the  transparency  of  all  tissues,  and  is  used  for 
terrestrial  and  fresh-water  animals.  Marine  animals  require  the  specific 
gravity  to  be  increased  to  1.148  or  even  higher. 

3.  Acetate  of  Alumina. — The  famous  Gannal  process,  formerly  so  much 
in  vogue  in  Europe,  consists  in  using  one  part  of  acetate  of  alumina,  with 
four  of  distilled  water,  either  as  an  injection,  when  it  is  said  it  will  prevent 
decomposition,  or  as  a  fluid  for  mounting  objects.  Its  destruction  of  bone  is 
an  objection  to  its  employment  under  certain  circumstances. 

4.  Creosote. — This  is  an  excellent  preservative,  but  requires  some  care 
in  its  preparation  with  water.  One  of  the  best  methods  is  to  mix  it  with 
water,  and  then  distil  the  mixture.  The  water  will  come  highly  charged 
with  the  creosote.  The  only  objection  to  the  employment  of  this  fluid,  is  its 
tendency  to  turn  the  preparation  brown.  An  excellent  fluid,  known  as  Mr. 
Thwaite's  fluid,  contains  creosote  as  an  ingredient,  and  is  thus  prepared  : 
To  sixteen  parts  of  distilled  water  add  one  part  of  pure  alcohol  and  a  few 
drops  of  creosote  :  stir  in  a  small  quantity  of  prepared  chalk,  and  then  filter: 
with  this  fluid  mix  an  equal  quantity  of  camphor-water,  and  strain  through 
a  piece  of  fine  linen. 

5.  Glycerine. — This  fluid,  now  to  be  obtained  at  most  o  the  drug-stores, 
forms  with  equal  parts  of  water  a  valuable  preservative  for  delicate  tissues, 
in  which  it  is  important  to  preserve  the  bright  colours.  Hence,  for  the  deli- 
cate colours  of  living  infusoria,  it  will  answer  better  than  any  other  fluid. 
If  the  glycerine  be  used  pure,  its  highly  refracting  properties  will  sometimes 
prevent  the  object  from  being  well  shown.  To  the  glycerine,  salt,  corro- 
sive sublimate,  spirit  of  wine,  or  creosote,  may  be  added,  if  desirable. 

6.  Canada  Balsam. — This  very  useful  material  is  employed  when  it  is 
desired  to  increase  the  transparency  of  an  object,  as  in  sections  of  teeth,  bone, 
&c,  or  in  some  instances,  to  mount  injectings  that  have  become  dried.  It 
may  be  used  with  heat  or  without,  and  directions  will  be  subsequently  given 
for  its  use  in  both  methods. 

7.  Salt  and  Water. — A  solution,  containing  five  grains  of  common  salt 
to  one  ounce  of  distilled  water,  will  preserve  many  animal  and  vegetable 
preparations.  Mr.  Quekett  mentions  that  the  common  objection  to  all  saline 
preservatives,  viz:  the  growth  of  conferval  in  them,  may  be  obviated  by 


58  INTRODUCTION. 

the  addition  of  a  few  drops  of  creosote  or  camphor  mixture.     This,  however, 
is  inferior  to  Goadby's  B-solution. 

8.  Naptha.  —  In  the  proportion  of  one  part  of  naptha  to  seven  or  eight  of 
water,  a  good  preservative  is  obtained  for  ordinary  objects.  It  is  stated  that 
this  mixture  is  now  generally  used  abroad  by  Messrs.  Hett,  Topping,  and 
others,  as  the  best  preservative  of  injected  preparations.  If  this  be  true, 
it  is  a  strong  recommendation  in  favour  of  its  employment. 

Dr.  Hannover,  in  Muller's  "Archives,"  1840,  recommends  the  employ- 
ment of  a  solution  of  chromic  acid  as  a  preservative  fluid,  and  also,  as  a 
fluid  in  which  soft  tissues  may  be  hardened  for  future  dissection.  In  a  weak 
state,  as  one  part  to  twenty  of  water,  pus,  mucus,  epithelium,  blood  corpuscles, 
and  other  delicate  structures,  are  well  preserved  :  when  the  solution  is  too 
strong,  the  tissues  acquire  a  yellow  or  even  red  colour. 

The  writer  has  not  used  this  solution  as  a  preservative  sufficiently  long 
to  test  its  merits,  but  can  speak  well  of  its  hardening  properties :  brain,  liver, 
and  other  soft  tissues,  after  being  deposited  in  this  solution  a  short  time, 
acquire  a  degree  of  hardness  sufficient  to  allow  of  very  thin  sections. 

The  following  excellent  general  directions  for  mounting  objects,  are  given 
by  Mr.  Quekett,  in  his  work  already  so  often  quoted :  "  For  all  large  speci- 
mens, such  as  injections,  the  spirit  and  water,  or  Goadby's  first  solution,  may 
be  used;  and  for  others,  either  the  creosote  or  glycerine  solutions,  as  those 
containing  saline  matter,  when  placed  either  between  glasses  simply,  or  in 
the  thin  glass  cells,  are  apt  to  crystallize  slowly,  and  interfere  with  the  objects 
that  are  mounted  in  them.  Goadby's  solution,  containing  both  salt,  alum, 
and  corrosive  sublimate,  will  keep  animal  structures  that  have  been  injected 
with  size  and  vermilion,  exceedingly  well ;  but  those  in  which  the  vessels 
are  filled  with  flake-white  will  have  that  substance  destroyed  in  a  few  hours; 
in  these  cases,  either  the  arsenical  or  the  spirit  and  water  only  should  be 
employed.  The  glycerine  fluid,  when  kept  for  some  time,  is  apt  to  become 
mouldy,  it  should,  therefore,  be  mixed  in  small  quantities,  and  then  only  a 
few  hours  before  it  is  required.  When  objects  are  to  be  mounted  in  either 
of  the  above  fluids,  it  must  be  laid  down  as  a  rule,  that  they  should  have 
been  soaking  for  some  hours  in  the  same  fluid,  or  in  a  fluid  of  a  similar 
kind  ;  this  should  be  more  particularly  attended  to,  when  the  preparation  has 
to  undergo  dissection  in  water,  previous  to  its  being  mounted.  It  has  often 
happened  to  the  author  to  find  a  preparation  that  had  been  dissected  in  water, 
and  mounted  in  a  cell  in  spirit  and  water  immediately  after,  completely 
covered  over  with  small  air-bubbles  in  a  few  hours,  from  the  slow  admixture 
of  the  two  fluids.  With  Goadby's  solution,  it  does  not  so  often  happen  ;  but 
with  this,  a  white  sediment  will  be  sometimes  deposited  in  the  bottom  of  the 


FLUIDS      FOR      MOUNTING      OBJECTS.  59 

cell    when   the    preparation    has    been    soaking    in    spirit    for   some   time 
previously." 

Objects  are  usually  mounted  in  one  of  four  ways.  These  are — 1,  the 
dry  way;  2,  in  Canada  balsam  with  heat;  3,  in  fluid;  4,  as  opaque  objects. 

l.-THE   DRY    WAY. 

This  method  is  adopted  in  mounting  objects  which  show  best  their 
peculiar  structure  without  the  addition  of  fluid  or  Canada  balsam.  Such 
objects  are  some  thin  sections  of  bone  and  teeth,  some  kinds  of  hairs, 
some  urinary  deposits,  &c.  It  may  be  stated  here,  however,  that  unless 
a  particular  method  is  known,  from  repeated  trials,  to  be  superior  to  all 
others,  the  different  methods  should  be  adopted  with  a  view  of  trial,  where 
the  specimens  are  large  enough  to  divide  in  this  way.  Now,  although  some 
sections  of  bone  and  teeth  show  better  for  being  mounted  in  the  dry  way,  yet 
some  others  show  better  in  Canada  balsam ;  the  choice  depending  in  some 
degree  on  the  thickness  of  the  section,  and  the  density  of  the  structure.  If 
the  specimen  to  be  mounted  be  a  rare  one,  and  the  quantity  small,  it  should 
be  examined  with  the  microscope  before  being  permanently  mounted.  This 
may  be  easily  done,  both  in  the  dry  way  and  in  fluid.  Having  determined 
to  mount  an  object  in  the  dry  way,  the  first  step  is,  to  properly  cleanse  the 
specimen,  as  it  will  be  always  found,  on  examination,  that,  no  matter  how 
clean  an  object  may  appear  to  the  eye,  or  even  with  a  low  power  of  the 
microscope,  numerous  particles  of  dust  will  be  found  on  it. 

These,  if  not  removed,  may  not  only  prevent  the  true  structure  of  the 
object  from  being  determined,  but  by  the  beginner  may  be  mistaken  for  part 
of  the  structure  itself.  Indeed,  M.  Robin  recommends  the  microscopic 
study  of  dust-particles  as  a  preliminary  to  the  proper  study  of  animal 
preparations. 

Ordinary  preparations  may  be  cleansed  by  soaking  them  for  a  few 
hours,  previous  to  mounting,  in  distilled  water,  or  by  washing  them  with  a 
small  syringe  and  water.  Specimens  that  contain  grease,  as  sections  of 
bone,  &c,  may  be  cleansed  by  soaking  them  in  sulphuric  ether  or  spirits 
of  turpentine.  After  being  properly  cleansed,  the  specimen  must  then  be 
allowed  to  dry.  If  the  object  be  a  thin  one,  it  is  to  be  placed  upon  a  plain 
glass  slide,  and  covered  with  a  square  or  circular  piece  of  thin  glass,  a  little 
larger  than  the  object.  The  cover  is  then  pressed  firmly  down,  and  fastened 
with  thick  gold-size,  or  with  the  compound  cement,  or  the  diamond  cement, 
always  being  careful  to  paint  on  a  thin  coat  of  cement,  at  first,  and  a  thicker 
one  afterwards. 

If  the  object  be  too  thick  to  allow  the  cover  to  approach  the  slide,  the 
intervening  space  may  be  filled  up  by  small  pieces  of  paper,  card-board,  or 
thin  gutta-percha,  having  a  hole  punched  out  in  the  centre,  a  little  larger 


60  INTRODUCTION. 

than  the  object.     These  are  first  to  be  cemented  to  the  slide ;  the  object  is 
then  deposited  in  its  place,  and  the  cover  cemented  down  as  before. 

If  the  specimen  to  be  mounted  be  a  section  of  lung,  gland,  intestine,  &c, 
and  some  of  these  show  their  structure  very  well  when  mounted  in  the  dry 
way,  one  of  the  different  forms  of  cells  before  described,  may  be  used.  The 
depth  of  the  cell  being  always  proportioned  to  the  thickness  of  the  object,  it 
being  desirable  to  have  the  surface  of  the  object  as  near  the  cover  as  possi- 
ble, the  more  readily  to  receive  the  light.  The  cover  is  then  to  be  applied 
and  cemented  with  the  gold-size. 

2. -CANADA   BALSAM   WITH    HEAT. 

This  method  is  adopted  in  mounting  thin  objects  that  require  to  be  made 
more  transparent  than  they  are  in  the  dry  state,  and  at  the  same  time  such 
as  will  not  be  injured  by  heat.  Sections  of  bone  and  teeth  are  often  mounted 
in  this  way.  The  Canada  balsam,  or,  as  it  is  sometimes  called,  balsam  of 
fir,  used  in  this  manipulation,  should  be  rather  old  and  thick,  as  it  then 
requires  less  heat  to  harden  it  than  when  new  and  thin. 

The  best  way  of  keeping  it  for  use,  is  a  tall  vial  with  a  narrow  mouth. 
From  this  vial  the  balsam  may  be  dropped  on  the  plain  slide  or  object,  and 
will  be  found  a  better  plan  of  proceeding  than  that  usually  recommended, 
viz:  of  keeping  the  balsam  in  a  wide-rnouthed  jar,  and  taking  the  desired 
quantity  by  means  of  a  glass  rod.  In  this  latter  method,  it  will  not  only 
be  found  difficult  to  obtain  the  sufficiently  small  quantity  required,  but  the 
portion  taken  will  contain  a  much  greater  quantity  of  air-bubbles  than  when 
the  balsam  is  dropped  from  the  vial.  The  vial  should  be  only  about  half- 
full,  and  allowed  to  stand  uncorked  for  a  day  or  so,  in  order  that  the  air- 
bubbles,  may  rise  to  the  surface,  and  burst.  , 

The  object  having  been  properly  cleansed  and  dried,  as  directed  in 
mounting  objects  in  the  dry  way,  it  is  to  be  deposited  in  the  centre  of  the 
glass  slide,  and  a  sufficient  quantity  of  balsam  to  be  dropped  on  it  to  com- 
pletely cover  it.  For  most  objects,  one  small  drop  will  answer.  The  slide 
is  then  to  be  seized  by  means  of  an  ordinary  wire  forceps  with  flat  blades 
(covered  with  leather,  if  desired),  and  held  over  the  flame  of  a  spirit-lamp; 
care  being  taken  to  approach  the  flame  gradually;  otherwise  the  slide,  if 
not  broken,  will  have  an  infinite  number  of  fine  cracks  in  it,  which  will 
effectually  spoil  its  further  use.  The  slide  is  to  be  held  over  the  flame  at 
short  intervals  until  all  traces  of  air-bubbles  are  removed,  care  at  the  same 
time  being  taken  to  prevent  the  boiling  of  the  balsam. 

When  there  is  no  longer  any  appearance  of  air-bubbles,  the  slide  is  to  be 
removed  from  the  flame,  and  a  square  or  circular  piece  of  thin  glass,  previ- 
ously cleansed  and  ready,  is  to  be  gently  warmed,  not  heated,  and  pressed 
upon  the  object.     The  superfluous  balsam  will  escape  beyond  the  thin  glass, 


CANADA     BALSAM.  61 

and  when  cold  may  be  removed  with  a  knife,  and  subsequently  perfectly 
cleansed  by  means  of  a  rag  dipped  in  ether.  A  modification  of  this  plan 
of  mounting  is,  to  place  the  slide  containing  the  balsam  upon  a  piece  of  tin 
kept  for  the  purpose,  about  four  inches  square,  with  the  edges  bent  up,  to 
prevent  the  glass  from  slipping  off  (a  cover  to  the  ordinary  seidlitz-powder 
box  will  answer  very  well),  and  to  hold  this  over  the  flame  of  the  lamp  by 
means  of  the  wire  forceps.  In  this  plan,  there  is  less  danger  of  cracking 
the  glass,  but  no  other  advantage. 

Still  another  method  is,  to  have  a  small  table  made  of  tin,  supported  by 
wire  legs,  sufficiently  high  to  admit  the  spirit-lamp  under  it.  The  slide  is 
then  placed  on  the  table,  and  heated  to  the  necessary  point  as  before.  A 
little  experience  will  enable  one  to  judge  how  much  heat  is  necessary  to 
sufficiently  harden  the  balsam  and  dispel  the  air-bubbles. 

Objects  may  be  mounted  in  Canada  Balsam  without  heat,  by  dropping  the 
balsam  on  the  preparation,  as  before,  and  allowing  it  to  remain  uncovered 
for  a  day  or  two.  In  this  time,  the  air-bubbles  will  usually  burst,  or  will 
rise  to  the  surface,  where  they  may  be  broken  by  means  of  a  needle-point. 
When  there  are  no  longer  traces  of  air  in  the  balsam,  which  may  at  any 
time  be  discovered  by  placing  the  slide  under  the  microscope,  and  examin- 
ing it  with  a  low  power,  the  thin  glass  is  to  be  warmed,  and  pressed  upon 
the  object,  when  the  superfluous  balsam  will  escape.  The  preparation  is  to 
be  set  aside,  and  allowed  to  harden  by  drying  before  the  escaped  balsam 
can  be  removed.  This  method  of  course  requires  a  much  longer  time, 
before  the  object  can  be  properly  finished,  than  when  heat  is  employed,  and 
is  only  adapted  to  cases  where  heat  would  injure  the  object. 

When  injected  specimens  are  to  be  mounted  in  balsam,  they  should  be 
placed  in  cells ;  one  of  these  of  proportionate  size  and  depth  having  been 
selected,  and  cleaned  by  means  of  ether,  or  a  solution  of  borax  and  water, 
the  object  is  to  be  deposited  in  the  cell,  and  the  unoccupied  space  filled  with 
the  balsam  dropped  from  the  vial.  The  balsam  should  not  overrun  the  cell, 
but  rise  a  little  above  the  level  of  its  edge.  The  slide  is  to  be  set  aside  for 
a  day,  where  it  will  be  free  from  dust,  in  order  that  the  air-bubbles  may 
rise  to  the  surface,  and  burst.  When  there  is  no  longer  any  trace  of  air  in 
the  balsam,  a  square  or  circular  cover  of  thin  glass,  properly  cleaned,  and 
a  little  smaller  than  the  outer  circumference  of  the  cell,  is  to  be  slightly 
warmed  in  the  flame  of  a  spirit-lamp,  and  placed  over  the  cell.  If  the 
cover  does  not  touch  the  cell  at  every  point,  gentle  pressure  is  to  be 
employed  until  the  superfluous  balsam  is  pressed  out. 

A  sharp-pointed  knife  may  then  be  used  to  remove  the  balsam  outside  the 
cell,  when  a  thin  coat  of  the  gold-size  is  to  be  applied  around  the  edges  of 
the  thin  glass,  so  as  to  cement  it  to  the  cell.     In  a  few  hours  or  a  day, 


62  INTRODUCTION. 

another  and  thicker  coat  of  the  size  is  to  be  applied,  or  a  coat  of  the  asphal- 
tum  or  sealing-wax  cement. 

Should  a  bubble  of  air  enter  the  cell  during  the  operation  of  adjusting 
the  cover  or  removing  the  balsam  around  its  edges,  the  cover  must  be  slip- 
ped half  way  off  the  cell,  and  another  drop  of  the  balsam  added. 

When  the  last  coat  of  cement  is  quite  dry,  any  trace  of  balsam  may  be 
removed  from  the  slide  or  cover  by  means  of  a  linen  rag  or  old  cambric 
handkerchief,  dipped  in  ether,  care  being  taken  not  to  touch  the  cement,  as 
all  these  are  acted  on  more  or  less  by  the  ether. 

3.-0  EJECTS  MOUNTED  IN  FLUID. 

Objects  mounted  in  fluid  are  usually  preserved  in  some  of  the  different 
forms  of  cells  already  described  ;  but  some  very  delicate  structures — such  as 
muscular  fibre,  fibres  of  the  crystalline  lens,  &c. — requiring  high  powers 
for  examination,  should  be  mounted  as  fiat  (as  it  is  termed)  as  possible. 
With  preparations  of  this  order,  the  following  method  may  be  adopted :  A 
clean  plain  glass  slide  having  been  selected,  the  object  is  to  be  deposited  in 
the  centre:  if  there  are  several  specimens  of  the  same  objects,  as  several 
fibres  of  muscle,  they  should  be  slightly  separated  by  means  of  a  needle- 
point. A  drop  or  two  of  the  mounting-fluid  is  then  to  be  added  by  means 
of  a  pipette,  when  the  thin  glass  cover,  square  or  round,  is  to  be  placed 
gently  on  the  fluid.  If  the  object  has  escaped  to  the  edge  of  the  thin  glass, 
it  will  be  much  easier  to  remove  the  cover,  and  begin  again,  than  attempt  to 
push  back  the  specimen  with  a  needle.  A  very  good  method  to  secure  the 
object  in  any  desired  position,  is  to  moisten  it  with  a  little  water,  or  spirit 
and  water,  and  allow  this  to  evaporate,  when  the  object  will  adhere  to  the 
surface  of  the  glass.  The  fluid  that  escapes  beyond  the  edges  of  the  thin 
glass  may  be  removed  by  means  of  a  camel's-hair  pencil,  when  a  very  thin 
coating  of  the  gold-size  is  to  he  applied  around  the  edges  of  the  cover. 
When  this  is  dry,  another,  and  sometimes  a  third  coat,  must  be  added  in  the 
same  way.  When  quite  dry  and  hard,  the  whole  slide  may  be  cleaned 
with  a  solution  of  borax  and  water.  This  solution  is  at  once  cheap,  very 
cleansing,  and  should  be  always  at  hand. 

The  thin  glass  cell,  or  the  cell  made  with  any  of  the  cements,  or  the 
white-lead,  &c,  as  previously  described,  may  be  also  used  for  mounting 
this  description  of  objects.  When  the  thjn  glass  cell  can  be  obtained,  this 
will  be  found  preferable  to  all  others. 

Portions  of  injected  preparations — such  as  sections  of  kidneys,  liver,  intes- 
tines, &c. — of  different  degrees  of  thickness,  require  mounting  in  cells  of 
proportionate  depth.  The  method  is  nearly  the  same  as  in  mounting  in 
cells  with  Canada  balsam.  The  object  being  placed  in  the  cell,  the  fluid  is 
to  be  added  either  from  a  vial  or  by  means  of  a  dropping-tube,  so  as  to  fill 


OPAQUE      OBJECTS.  63 

the  cell  completely  full  without  overrunning  it.  The  cover  is  then  to  be 
gently  dropped  upon  the  cell,  and  the  escaped  fluid  must  be  carefully  absorbed 
by  means  of  thin  bibulous  paper,  or,  still  better,  by  a  camePs-hair  pencil. 
If  a  bubble  of  air  has  entered  the  cell,  the  cover  is  to  be  half  drawn  off, 
and  more  fluid  added ;  a  thin  coat  of  cement  is  then  to  be  applied,  and  the 
object  finished,  as  already  directed. 

4. -OPAQUE  OBJECTS. 
It  has  been  found  that  some  objects,  although  sufficiently  transparent  to 
allow  the  light  to  pass  through  them,  yet  show  their  structure  better  when 
viewed  upon  a  dark  ground,  or,  as  it  is  termed,  viewed  as  opaque  objects. 
Any  transparent  object  may  be  made  opaque,  by  turning  away  the  mirror 
from  the  stage  of  the  microscope,  or  by  interposing  a  dark  stop  between  the 
object  and  the  mirror.  Both  these  methods,  however,  may  be  troublesome 
at  times,  and  objects  that  require  a  permanent  dark  ground  may  be  mounted 
opaque  by  placing  a  small  circle  of  black  paper  or  blackened  silk  (court 
plaster  will  answer  very  well)  beneath  the  object,  if  it  be  mounted  dry  ;  or, 
if  mounted  in  balsam  or  fluid,  either  the  paper  or  silk  may  be  pasted  on  the 
under  side  of  the  slide.  The  object  should  be  covered  with  thin  glass,  as 
in  other  methods  of  mounting,  to  prevent  injury  from  dust. 

Labelling  Slides. — The  best  method  of  labelling  slides,  is  to  write  the 
name  of  the  object,  and  the  particular  point  it  is  intended  to  exhibit,  on  the 
right-hand  side  of  the  slide,  with  a  writing  diamond,  such  as  is  used  in 
cutting  the  thin  glass.  On  the  left-hand  side  of  the  object  may  be  written 
the  date  of  the  mounting,  the  style  of  the  mounting,  whether  dry  or  in 
balsam,  or  the  name  of  the  fluid  used.  This  will  be  readily  seen  to  be 
desirable  information,  as  when  several  hundred  objects  are  collected  together, 
it  is  impossible  to  remember  the  peculiarities  of  each  without  some  memo- 
randum. The  advantages  of  each  different  mounting  may  be  thus  compared 
when  several  specimens  of  the  same  object  are  mounted  in  different  styles, 
and  this  experience  may  be  a  guide  in  future  preparations. 

Some  prefer  to  cover  the  slides  with  paper,  either  plain  or  ornamented, 
and  write  the  contents  of  the  slide  with  ink.  In  pursuing  this  method,  a 
circle  is  cut  from  the  centre  of  the  paper  by  means  of  a  saddler's-punch  a 
little  larger  than  the  object;  the  paper  is  then  pasted  on  by  means  of  the 
gum-arabic  cement,  and  the  edges  turned  down  over  the  edge  of  the  slide; 
another  similar  piece  of  paper  is  pasted  on  the  opposite  side  of  the  slide, 
and  neatly  trimmed  off.  In  this  method,  there  is  usually  less  danger  of 
breaking  the  thin  glass  cover  in  subsequent  handling,  but  it  will  be  found  to 
consume  considerable  time,  and,  unless  very  well  done,  does  not  make  so 


64  INTRODUCTION. 

neat  an  appearance  as  the  first  method :  farther,  it  cannot  be  well  employed 
when  any  form  of  deep  cell  is  used. 

Cabinets. — For  the  purpose  of  preserving  microscopical  objects  free  from 
dust  and  from  danger  of  breakage,  cabinets  of  different  construction  are 
employed.  Where  economy  in  room  is  not  consulted,  those  made  with 
shallow  drawers,  having  a  depth  of  about  half  an  inch,  will  be  found  the 
most  convenient.  In  these  the  slides  all  lie  on  their  flat  surfaces,  where 
any  particular  one  may  be  more  readily  reached  than  when  they  are  placed 
on  their  edges.  There  is  also  in  the  former  method  less  danger  of  the  cells 
leaking  or  their  covers  being  broken. 

A  favourite  method  with  some,  and  one  occupying  much  less  room,  is  the 
employment  of  drawers  one  inch  deep,  in  which  racks  are  placed  at  proper 
distances  to  receive  the  slides  on  their  edges.  This  is  the  most  compact 
sort  of  cabinet,  and  two  or  three  thousand  slides  may  be  thus  preserved  in 
a  very  small  space.  The  objections  to  the  plan  are,  the  difficulty  of  readily 
finding  any  desired  slide,  as  you  only  can  see  the  edges  of  the  glass,  and 
not  the  object,  and  also  the  danger  of  breakage  to  the  cells  containing  fluid. 
A  method,  combining  safety  and  compactness,  is  the  employment  of  boxes 
fitted  with  racks,  and  each  box  capable  of  containing  two  dozen  slides 
placed  on  their  edges.  The  boxes  are  then  placed  on  their  ends  between 
permanent  partitions  in  the  cabinet;  and  when  arranged  and  labelled 
according  to  subjects,  any  particular  box  or  object  may  be  readily  reached, 
and  all  the  slides  while  in  the  cabinet  rest  on  the  flat  surfaces. 

Still  another  method  is,  to  have  boxes  made  in  the  shape  of  books,  and 
filled  with  racks,  so  as  to  contain  two  dozen  objects.  The  cover  of  the  box 
may  be  fastened  by  means  of  a  clasp,  and  the  boxes,  when  arranged  in  a 
book-case  or  on  the  mantel-piece,  have  a  neat  appearance.  The  objects  are 
kept  in  the  horizontal  position,  and  being  arranged  in  subjects,  are  very 
accessible. 

In  the  preparation  of  the  foregoing  Introduction,  valuable  assistance  has 
been  derived  from  the  following  works,  to  which  the  student  is  referred  for 
more  complete  accounts  of  some  methods  of  Manipulation:  "Quekett's 
Practical  Treatise  on  the  Microscope,"  "Anatomical  Manipulation,  by  Tulk 
and  Henfrey,"  and  "Du  Microscope  and  et  des  Injections,  par  Ch.  Robin." 


MICROSCOPIC  ANATOMY 


THE     HUMAN    BODY 


PART     I.  — THE     FLUIDS. 

The  constituents  which  enter  into  the  formation  of  the  body,  and 
by  the  combination  of  which  the  human  frame  is  built  up,  naturally 
resolve  themselves  into  two  orders,  Fluids  and  Solids,  the  latter 
proceeding  from  the  former. 

In  accordance  with  this  natural  division  of  the  elements  which 
enter  into  the  composition  of  the  body,  it  is  intended  to  divide  this 
work  into  two  parts :  the  first  of  which  will  treat  of  those  components 
of  our  frame-work  which  are  first  formed — the  Fluids  ;  and  the 
second  will  be  devoted  to  the  consideration  of  those  constituents 
which  proceed  from  the  fluid  elements,  viz :  the  Solids. 

Of  the  fluids  themselves,  it  is  difficult  to  determine  upon  any  sub- 
division which  shall  be  altogether  without  objection ;  perhaps  the 
most  practicable  and  useful  division  of  them  which  can  be  made  is, 
into  organized  and  unorganized. 

To  the  above  arrangement  of  the  fluids  the  following  exception 
might  be  taken :  all  the  fluids  in  the  animal  economy,  it  may  be  said, 
are  to  be  considered  as  organized,  inasmuch  as  their  elaboration  is 
invariably  the  result  of  organization.  But  it  is  intended  that  the 
words  organized  and  unorganized,  when  applied  to  the  fluids  in 
this  work,  should  have  a  very  different,  as  well  as  a  more  precise 
signification,  and  that  those  fluids  only  should  be  called  organized 
which  contain  in  them,  as  essential,  or,  at  all  events,  as  constant 
constituents,  certain  solid  and  organized  particles ;  while  those  liquids 

5 


66 


THE     FLUIDS. 


which  are  compounded  of  no  such  solid  matters,  as  essential  portions 
of  them,  should  be  termed  unorganized. 

In  the  first  category,  the  lymph,  chyle,  blood,  mucus,  as  normal, 
and  pus,  as  an  abnormal  fluid,  would  find  their  places  together  with 
the  milk  and  semen.  The  fluids  of  this  class,  it  will  be  seen,  belong 
especially  to  nutrition  and  reproduction,  and  admit  also,  naturally, 
of  arrangement  into  two  series:  in  the  first,  those  fluids  which  are 
concerned  in  the  nutrition  and  growth  of  the  species  itself  would  be 
comprised — as  lymph,  chyle,  and  blood ;  and  in  the  second,  those 
liquids  which  appertain  to  the  reproduction,  nutrition  and  growth  of 
the  new  species,  as  the  milk  and  semen,  would  be  admitted. 

In  the  second  category,  viz :  that  of  unorganized  fluids,  the  per- 
spirable Jluid.  the  saliva,  the  bile,  and  the  urine,  as  well  as  probably 
the  fluid  of  the  pancreas,  and  of  certain  other  glandular  organs, 
would  be  found. 

This  arrangement  of  the  fluids  of  the  human  body  might  be 
represented  tabularly,  thus : 


FLUIDS. 

ORGANIZED. 

UNORGANIZED. 

FIRST     SERIES. 

Perspirable  fluid. 

Normal  : 

Saliva. 

Lymph. 

Bile. 

Chyle. 

Urine. 

Blood. 

Pancreatic  fluid  (?) 

Mucus. 

&.C.,  &c,  &c. 

Abnormal  : 

Pus. 

SECOND     SERIES. 

Milk. 

Semen. 

If  the  terms  organized  and  unorganized  be  objected  to,  the 
words  compound  and  simple  might  take  their  places,  and  would  well 
express  the  distinction  which  characterizes  the  two  series  of  fluids ; 
the  former  appellation  being  applied  to  those  fluids  which  are  com- 
pounded of  both  a  solid  and  a  fluid  element,  and  the  latter  to  those 
which  do  not  possess  this  double  constitution. 


ORGANIZED     FLUIDS. 


ART.    I.  — THE  LYMPH  AND  THE   CHYLE. 

It  will  perhaps  render  the  description  of  the  lymph  and  the  chyle 
more  intelligible,  if  the  observations  which  we  shall  have  to  make  on 
these  fluids  are  preceded  by  a  short  sketch  of  the  lymphatic  system 
itself.  This  system  consists  of  vessels  and  of  glands,  which  are  of 
the  kind,  which  has  been  denominated  conglobate.  The  vessels  have 
many  of  the  characters  of  veins,  commencing  as  mere  radicles,  which 
unite  with  each  other  to  form  larger  trunks,  and  their  interior  surface 
is  provided  with  valves :  they  arise  from  all  parts  of  the  system,  even 
the  most  remote ;  those  of  the  lower  extremities  and  abdominal  vis- 
cera form  by  their  union  the  thoracic  duct,  which,  running  along  the 
left  side  of  the  spinal  column,  unites  with  the  left  sub-clavian  vein, 
near  its  junction  with  the  internal  carotid,  its  contents  becoming 
mingled  with  the  torrent  of  blood  in  that  vein.  The  lymphatics  of 
the  left  side  of  the  head  and  neck,  as  well  as  those  of  the  arm  of  the 
corresponding  side,  unite  with  the  same  thoracic  duct,  in  the  superior 
part  of  its  course.  On  the  right  side,  however,  a  smaller  separate 
duct,  formed  by  the  union  of  the  lymphatics  of  the  upper  part  of  that 
side  of  the  body,  is  frequently  met  with,  and  this  empties  itself  into 
the  right  sub-clavian  vein.  All  these  lymphatic  vessels,  in  their 
course,  pass  through  the  glands  above  referred  to,  and  in  which  the 
fluid  or  lymph  contained  by  them  doubtless  undergoes  further  elabora- 
tion. The  lymphatics  are  remarkable  for  their  equal  and  small 
diameter,  which  allows  of  the  passage  of  the  lymph  through  them  by 
mere  capillary  attraction;  they  are  also  to  be  regarded  as  the  chief, 
though  not  the  exclusive,  agents  of  absorption  in  the  system,  the  veins 
likewise  taking  part  in  this  process. 

The  lymphatics  of  the  upper  and  lower  portions  of  the  body  imbibe 
and  carry  along  with  them  the  various  effete  matters  and  particles 
which  are  continually  being  given  off  by  the  older  solid  constituents 
of  our  frame,  and  which  are  as  constantly  undergoing  a  process  of 


68  ORGANIZED     FLUIDS. 

regeneration ;  these  they  redigest  and  reassimilate,  into  a  fluid  endowed 
with  nutritive  properties,  denominated  lymph,  and  which  is  poured 
into  the  thoracic  duct. 

Those  lymphatics,  however,  which  arise  on  the  surface  of  the  small 
intestines,  and  which,  passing  through  the  mesentery,  join  the  thoracic 
duct,  have  received  a  special  appellation,  being  called  lacteals:  this 
name  has  been  bestowed  upon  them  on  account  of  the  milk-like 
appearance  of  the  fluid  which  they  contain,  viz :  the  chyle,  a  fluid 
derived  from  the  digestion  of  the  various  articles  of  food  introduced 
into  the  stomach,  and  which  also  is  emptied  into  the  thoracic  duct. 

But  the  lacteals  are  not  always  filled  with  chyle;  they  are  only  to 
be  found  so  when  digestion  has  been  fully  accomplished;  when  an 
animal  is  fasting,  they,   like   other   lymphatics,  contain  merely  lymph. 

The  contents  of  the  thoracic  duct  likewise  vary :  it  never  contains 
pure  chyle,  but  during  digestion  a  fluid  composed  of  both  chyle  and 
lymph,  the  former  predominating,  and  digestion  being  completed,  it  is 
filled  with  lymph  only. 

It  follows  therefore  that,  if  we  are  desirous  of  ascertaining  the 
proper  characters  of  chyle,  our  observations  should  not  be  conducted 
on  the  fluid  of  the  thoracic  duct,  but  on  that  of  the  lacteals  themselves. 
It  is  a  common  error  to  regard  and  to  describe  the  contents  of  that 
duct,  at  all  times  and  under  all  circumstances,  as  chyle,  and  it  is  one 
which  has  led  to  the  formation  of  some  false  conclusions. 

We  will  describe  first  the  lymph,  next  the  chyle,  and  lastly  the 
mingled  fluid  presented  to  us  in  the  thoracic  duct. 

The  lymph  is  a  transparent  colourless  liquid,  exhibiting  a  slightly 
alkaline  reaction,  and  containing,  according  to  the  analysis  of  Dr.  G. 
O.  Rees,  0'  120  of  fibrin,  with  merely  a  trace  of  fatty  matter. 

When  collected  in  any  quantity,  and  left  to  itself,  the  lymph,  like 
the  chyle,  separates  into  a  solid  and  a  fluid  portion :  the  solid  matter 
consists  of  fibrin,  and  contains  mixed  up  with  its  substance  numerous 
granular  and  spherical  corpuscles,  identical  with  the  white  globules  of 
the  blood ;  the  serum  is  transparent,  and  contains  but  few  of  the  cor- 
puscles referred  to. 

The  chyle  is  a  whitish,  opaque,  oleaginous,  and  thick  fluid,  also 
manifesting  an  alkaline  reaction,  and  containing,  according  to  the 
analysis  of  the  gentleman  above  mentioned,  0 '  370  of  fibrin,  and  3 '  601 
of  fatty  matter.* 

*  See  article  "Lymphatic  System,"  by  Mr.  Lane,  in  Cyclopedia  of  Anatomy  and 
Physiology,  April,  1841. 


THE  LYMPH  AND  THE  CHYLE.  69 

There  are  present  in  it  solid  matters  of  several  kinds. 

1st,  Minute  particles,  described  by  Mr.  Gulliver,*  and  which  con- 
stitute the  "molecular  base"  of  the  chyle,  imparting  to  it  colour  and 
opacity :  their  size  is  estimated  from  the  3 @ fo  o  to  the  24^00  0I" an  inch 
in  diameter;  they  are  "remarkable"  not  only  for  their  minuteness, 
but  also  for  "their  equal  size,  their  ready  solubility  in  aether,  and  their 
unchangeableness  when  subjected  to  the  action  of  numerous  other 
reagents  which  quickly  affect  the  chyle  globules." 

Mr.  Gulliver  has  ascertained  the  interesting  fact,  that  the  milky 
appearance  occasionally  presented  by  the  blood  is  due  to  the  presence 
of  the  molecules  of  the  chyle.  This  peculiar  appearance  of  the  blood, 
which  so  many  observers  have  observed  and  commented  upon,  but 
of  which  none  save  Mr.  Gulliver  have  offered  any  satisfactory 
explanation,  is  noticed  to  occur  especially  in  young  and  well-fed  ani- 
mals during  digestion ;  as  also  in  the  human  subject,  in  certain  path- 
ological conditions,  and  sometimes  in  connexion  with  a  gouty  diathesis. 

2d,  Granular  Corpuscles,  similar  to  those  contained  in  the  lymph, 
and  identical  with  the  white  globules  of  the  blood,  but  rather  smaller 
than  those,  and  which  will  be  fully  and  minutely  described  in  the 
chapter  on  the  Blood.  Mr.  Gulliver,  in  his  excellent  article  on  the 
chyle,  makes  the  remark  that  the  magnitude  of  the  globules  hardly 
differs,  from  whatever  part  of  the  lacteal  system  they  may  have  been 
obtained. 

The  granular  corpuscles  are  found  but  sparingly  in  the  chyle  of 
the  inferent  lacteals,  abundantly  in  that  of  the  mesenteric  glands 
themselves,  and  in  medium  quantity  in  the  efferent  lacteals,  and  in 
the  fluid  of  the  thoracic  duct. 

3d,  Oil  Globules,  which  vary  exceedingly  in  dimensions. 

4th,  Minute  Spherules,  probably  albuminous,  the  exact  size  or  form 
of  which  it  is  difficult  to  estimate,  and  which  are  not  soluble  in  aether, 
as  are  those  which  constitute  the  molecular  base. 

Chyle,  when  left  to  itself,  like  the  lymph,  separates  into  a  solid  and 
fluid  portion :  the  coagulum,  however,  is  larger  and  firmer  than  that 
of  lymph,  in  consequence  of  the  greater  quantity  of  fibrin  which  it 
contains;  it  is  also  more  opaque,  from  the  presence,  not  merely  of 
the  white  granular  corpuscles,  but  principally  of  the  molecules  of  the 
chyle;  the  serum  is  likewise  opaque,  the  opacity  arising  from  the 
same  cause,  the  peculiar  characteristic  molecules  of  the  chyle. 

*  See  Appendix  to  the  translation  of  Gerber's  General  Anatomy,  p.  89. 


70  ORGANIZED     FLUIDS. 

The  lymph  and  the  chyle  may  now  be  contrasted  together.  Both 
are  nutritive  fluids,  the  nutritious  ingredients  contained  in  the  one 
being  derived  from  the  redigestion  of  the  various  matters  which  are 
constantly  thrown  off  from  the  older  solids,  those  of  the  other  being 
acquired  from  the  food  digested  in  the  stomach:  the  one  is  a  transpa- 
rent fluid,  containing  but  little  fibrin,  a  trace  only  of  oil,  and  but  few 
white  corpuscles;  the  other  is  an  opaque,  white,  thick,  and  oily  fluid, 
more  rich  in  fibrin,  and  laden  with  molecules,  white  corpuscles,  oil 
globules,  and  minute  spherules;  the  one,  therefore,  is  less  nutritive 
than  the  other. 

It  has  been  asserted  that  chyle,  until  after  its  passage  through  the 
mesenteric  glands,  would  not  coagulate;  the  fallacy  of  this  assertion 
has  been  demonstrated  by  Mr.  Lane*,  who  collected  the  chyle  pre- 
vious to  its  entrance  into  those  glands,  and  found  that  it  did  coagulate, 
although  with  but  little  firmness,  less  indeed  than  it  exhibited  subse- 
quent to  its  passage  through  the  glands. 

We  now  come  to  consider  the  nature  of  the  contents  of  the  thoracic 
duct. 

These,  as  already  stated,  vary  according  to  the  condition  of  the 
animal;  thus,  if  it  be  fasting,  the  duct  contains  only  lymph;  if, 
however,  the  contents  be  examined  soon  after  a  full  meal,  they  will 
be  found  to  present  nearly  all  the  characters,  physical  and  vital,  of 
the  chyle,  and  in  addition,  especially  in  the  fluid  obtained  from  the 
upper  part  of  the  duct,  a  pink  hue,  said  to  be  deepened  by  exposure 
to  the  air. 

This  red  colour  has  been  noticed  by  many  observers,  and  it  is  now 
generally  agreed  that  it  arises  from  the  presence  in  the  fluid  of  the 
thoracic  duct  of  numerous  red  blood  corpuscles. 

The  question  is  not  as  to  the  existence  of  blood  discs  in  that  fluid, 
but  as  to  the  manner  in  which  their  presence  therein  should  be 
accounted  for,  whether  it  is  to  be  regarded  as  primary  and  essential, 
or  as  secondary  and  accidental. 

Most  observers  agree  in  considering  the  presence  of  blood  discs  in 
the  chyle  of  the  thoracic  duct  as  accidental,  although  they  account  for 
their  existence  in  it  in  different  ways. 

The  distinguished  Hewsonf  detected  blood  corpuscles  in  the 
efferent  lymphatics  of  the  spleen,  which  empty  their  contents  into  the 

*  See  Art.  "  Lymphatic  System,"  loc.  cit. 

f  Experimental  Inquiries,  part  iii.  Edited  by  Magnus  Falkoner.  London,  1777, 
pp.  122.  112.  135. 


THE  LYMPH  AND  THE  CHYLE.  71 

thoracic  duct,  and  in  this  way  he  conceived  that  the  fluid  of  that 
vessel  acquired  its  colour. 

The  accuracy  of  Hewson's  observation,  as  to  the  lymphatics  of  the 
spleen  containing  blood  corpuscles,  is  confirmed  by  Mr.  Gulliver,  of 
the  fidelity,  originality,  and  number  of  whose  remarks  on  the  micro- 
scopic anatomy  of  the  animal  fluids,  it  is  impossible  to  speak  in  terms 
of  too  high  praise.  Mr.  Gulliver  detected  blood  corpuscles  in  the 
efferent  lymphatics  of  the  spleen  of  the  ox  and  of  the  horse. 

Muller,  and  MM.  Gruby  and  Delafont,  attribute  the  presence  of 
blood  discs  in  the  chyle  to  the  regurgitation  of  a  small  quantity  of 
blood  from  the  sub-clavian  vein:  if  they  are  really  foreign  to  the 
chyle,  this  is  the  most  probable  channel  of  their  ingress. 

Mr.  Lane  thinks  that  the  division  of  the  capillaries,  which  necessa- 
rily takes  place  in  the  opening  of  the  duct,  allows  of  the  admission 
into  its  contents  of  the  blood  discs,  which  are  there  found.  Such  are 
the  several  ways  in  which  it  has  been  suggested  that  the  blood 
corpuscles  find  entrance  into  the  thoracic  duct. 

Mr.  Gulliver  has  noticed  that  the  blood  corpuscles  contained  in  the 
chyle  are  usually  much  smaller  than  those  taken  from  the  heart  of  the 
same  animal,  and  also,  that  not  more  than  one-fourth  of  the  entire 
number  present  their  ordinary  disc-like  figure,  the  remainder  being 
irregularly  indented  on  the  edges,  or  granulated.  The  first  of  these 
observations,  viz:  that  which  refers  to  the  smaller  size  of  the  blood 
corpuscles  found  in  the  chyle,  might  be  explained  by  supposing  that 
those  corpuscles  were  in  progress  of  formation,  and  that  they  had  not 
as  yet  attained  their  full  development;  the  other  remark,  as  to  the 
deformed  and  granulated  character  of  the  corpuscles,  might  be  recon- 
ciled with  the  former  explanation,  by  supposing  that  some  time  had 
elapsed  between  the  death  of  the  animal  and  the  examination  of 
the  fluid  of  the  thoracic  duct.  If  this  manner  of  accounting  for  the 
condition  presented  by  the  blood  corpuscles  of  the  chyle  should  be 
proved  to  be  insufficient,  which  I  myself  scarcely  think  it  will,  then 
the  only  other  mode  of  explaining  their  appearances  is  by  supposing 
that  their  presence  in  the  chyle  is  really  foreign,  and  that,  soon  after 
their  entrance  into  that  fluid,  the  blood  corpuscles  begin  to  pass 
through  those  changes,  indicative  of  commencing  decomposition, 
of  which  they  are  so  readily  susceptible. 

Leaving,  however,  for  the  present  the  question  of  the  origin  of  the 
red  corpuscles  of  the  blood,  which  will  have  to  be  more  fully  discussed 
hereafter,  we  will  in  the  next  place  bestow  a  few  reflections  upon  the 


72  ORGANIZED     FLUIDS. 

origin  of  the  white  corpuscles:  into  this  subject,  however,  it  is  not 
intended  to  enter  at  any  length  at  present,  but  merely  to  make  such 
observations  as  seem  more  appropriately  to  find  their  place  in  the 
chapter  on  the  Chyle  and  Lymph. 

It  has  been  noticed  that  the  white  corpuscles  occur  in  very  great 
numbers  in  the  chyle  obtained  from  the  mesenteric  and  lymphatic 
glands;  this  observation  has  led  to  the  supposition  that  the  white 
corpuscles  are  formed  in  those  glands. 

Upon  this  question,  as  upon  so  many  others,  Comparative  Anatomy 
throws  much  light.  It  has  been  ascertained  that  the  glands  referred 
to  have  no  existence  in  the  amphibia  and  in  fishes ;  in  birds,  too, 
they  are  only  found  in  the  neck.  Thus  it  is  evident,  that  the  lymphatic 
glands,  however  much  they  may  contribute  to  the  formation  of  the 
white  corpuscles,  are  not  essential  to  their  production. 

Corpuscles,  very  analogous  to  those  of  the  chyle  and  the  lymph, 
are  found  in  vast  quantities  in  the  fluid  of  the  thymus  gland  in  early 
life :  these  corpuscles  Hewson  considered  to  be  identical  with  the 
globules  of  those  fluids,  and  therefore  he  regarded  the  thymus  gland  as 
an  organ  of  nutrition,  and  as  an  appendage  to  the  lymphatic  system. 
In  this  opinion  he  has  been  followed  by  Mr.  Gulliver.  That  it  is  an 
organ  of  nutrition,  adapted  to  the  special  exigencies  of  early  life,  there 
can  be  no  doubt ;  but  that  it  is  an  appendage  of  the  lymphatic  system, 
and  that  the  globules  with  which  it  so  abounds  are  the  same  as  those 
of  the  lymph  and  chyle,  admits  of  much  diversity  of  opinion. 

The  globules  of  the  thymus  have  undoubtedly  striking  points  of 
resemblance  with  the  corpuscles  so  frequently  alluded  to;  they  have 
the  same  granular  structure;  they  are,  like  them,  colourless,  and  to 
some  extent  they  comport  themselves  similarly  under  the  influence  of 
certain  reagents. 

There  are  points,  however,  of  dissimilarity  as  well  as  of  resemblance; 
thus  they  are  usually  very  much  smaller  than  the  lymph  corpuscles, 
they  do  not  undergo  any  increase  of  size  when  immersed  in  water,  and 
acetic  acid  does  not  disclose  the  presence  of  nuclei. 

But,  above  all,  the  corpuscles  of  the  thymus  differ  from  those  of  the 
lymph  and  chyle  in  their  situation;  those  of  the  latter  fluids  are 
always  enclosed  in  vessels  in  lymphatics,  or  lacteal  lymphatics ;  while 
those  of  the  former  fluid,  that  of  the  thymus  gland,  are  extravascular, 
lying  loosely  in  the  meshes  of  the  cellular  tissue  which  forms  the 
foundation  of  the  substance  of  the  gland  itself. 

Now,  it  is  impossible  to  conceive  that  solid  organisms  of  such  a  size 


THE  LYMPH  AND  THE  CHYLE.  73 

as  the  corpuscles  of  the  thymus  can  enter  the  lymphatics  bodily ;  if 
they  are  received  into  the  circulation  at  all,  they  must  first  undergo 
a  disintegration  and  dissolution  of  their  structure. 

Both  Mr.  Gulliver  and  Mr.  Simon*  regard  the  corpuscles  of  the 
thymus  as  cytoblasts;  the  former,  however,  believes  that  before  their 
development  as  cytoblasts  they  enter  the  circulation,  while  the  latter  con- 
ceives that  they  are  developed  in  the  gland  itself  into  true  nucleated  cells. 

It  is  difficult  to  suppose,  with  Mr.  Simon,  that  the  small  and  uniform 
granular  corpuscles  of  the  thymus  are  developed  into  the  large,  complex 
and  curiously  constituted  true  secreting  cells  of  that  gland. 

Whether  this  be  the  case  or  not,  however,  it  would  appear  that 
Mr.  Simon  has  fallen  into  a  certain  amount  of  error  in  his  account  of 
the  structure  of  the  thymus  gland,  and  also  of  other  analogous  glands,  as 
well  as  in  the  generalizations  deduced  by  him  therefrom. 

Thus,  Mr.  Simon  states,  that  in  early  life  there  exists  in  the  thymus 
gland  "  no  trace  whatever  of  complete  cells ;"  that  it  is  only  in  later 
life  that  nucleated  cells  are  formed,  and  that  these  are  developed  out 
of  the  granular  corpuscles  already  referred  to,  and  which  are  alone 
present  in  the  gland  in  the  first  years  of  its  existence.  The  same 
statements  are  applied  to  the  thyroid  body. 

But  Mr.  Simon  does  not  rest  here :  he  regards  the  long  persistence 
of  the  corpuscles,  which  he  states  are  to  be  found  in  all  those  glands 
which  secrete  into  closed  cavities,  in  the  condition  of  cytoblasts,  as 
constituting  a  remarkable  and  important  distinction  between  the  glands 
in  question  and  the  true  secreting  glands  which  are  furnished  with 
excretory  ducts. 

These  observations  are  to  a  considerable  extent  erroneous,  as  is 
proved  by  the  fact  that  true  nucleated  cells  are  to  be  met  with 
abundantly  in  the  thymus  gland  of  still-born  children,  and  also  in 
the  thyroid  body  and  supra-renal  capsule  ;  in  the  last,  indeed,  almost 
every  cell  is  nucleated. 

On  this  supposed  essential  structural  distinction  between  the  true 
glands  which  are  furnished  with  excretory  ducts,  and  those  anomalous 
ones  which  are  destitute  of  such  ducts,  Mr.  Simon  founds  some 
general  deductions. 

It  is  known  that  the  functions  performed  by  the  glands  without 
ducts  are  of  a  periodic  and  temporary  character,  while  those  discharged 
by  the  true  glands  are  of  a  permanent  and  constant  nature. 

*  Prize  Essay  on  the  Thymus  Gland.    London,  4to.,  1846. 


74  ORGANIZED     FLUIDS. 

It  is  also  considered  by  some  physiologists  that  the  nucleus  of  every 
nucleated  cell  is  the  only  true  and  necessary  secreting  structure. 

These  views  of  the  nature  of  the  functions  performed  by  the 
anomalous  glands,  and  of  the  importance  of  the  nucleus,  being  adopted 
by  Mr.  Simon,  he  thence  draws  the  inference  that  the  cytoblastic 
condition  of  the  cells  of  the  thyroid,  thymus,  and  other  analogous 
glands,  is  precisely  that  which  is  required  by  organs  which  are  called 
only  into  action  periodically,  and  in  which  great  activity  prevails  at 
certain  periods. 

This  theory  is  ingenious,  but  it  has  been  seen  that  the  main  fact 
upon  which  it  rests  is  for  the  most  part  erroneous ;  and,  the  basis  of 
the  theory  being  removed,  the  theory  itself  must  fall. 

In  order  that  it  may  be  seen  that  the  opinions  entertained  by 
Mr.  Simon,  in  his  Essay  on  the  Thymus,  have  not  been  over-stated,  I 
will  introduce  a  few  passages  therefrom  : 

"Thus,  while  the  completion  of  cells,  within  the  cavities  of  the 
thyroid  gland,  is  assuredly  a  departure  from  the  habitual  state  of  that 
organ,  and  probably  the  evidence  of  protracted  activity  therein ;  it  is 
yet  just  such  a  direction  as  may  serve  even  better  than  uniformity  to 
illustrate  the  meaning  of  the  structures  which  present  it;  for  it 
shows,  beyond  dispute,  that  the  dotted  corpuscles  are  homologous  with 
the  cytoblasts  of  true  glands."  (p.  79.) 

"In  the  thymus  one  would  at  first  believe  a  similar  low  stage  of 
cell  development  to  be  universal ;  for  in  examining  the  contents 
of  the  gland  in  early  life,  one  finds  no  trace  whatever  of  complete  cells. 
The  dotted  corpuscles  are  undoubtedly  quite  similar  to  those  which 
we  have  recognised  as  becoming  the  nuclei  of  cells  in  the  thyroid 
body,  and  in  other  organs ;  there  is  abundant  room  for  conjecturing 
them  to  be  of  a  correspondent  function — to  be,  in  fact,  true  cytoblasts; 
■but  the  arguments  for  this  point  cannot  be  considered  quite  conclu- 
sive, without  some  additional  evidence." 

"  The  completion  of  a  cell,  from  the  isolation  of  so  much  of  the 
secreted  product  as  is  collected  round  each  cytoblast,  is  a  very  frequent 
secondary  process.  In  the  true  glands  it  is  very  frequent,  in  those 
without  ducts  exceptional."  (p.  84.) 

With  one  other  remark  on  the  corpuscles  of  the  thymus,  we  will 
conclude  this  short  chapter;  mixed  up  with  those  corpuscles  are 
frequently  to  be  noticed  many  nucleated  globules,  in  every  way  similar 


THE  LYMPH  AND  THE  CHYLE.  75 

to  the  white  corpuscles  of  the  blood,  but  very  distinct  from  the  true 
cell  corpuscles  of  the  gland;  the  nucleus  of  these  white  globules  is  of 
nearly  the  same  size  as  the  dotted  corpuscles  themselves.  Is  there 
any  relation  between  this  coincidence  in  size  ? 

We  now  pass  to  the  consideration  of  the  most  important  fluid  in 
the  animal  economy,  viz:  the  blood. 


76  ORGANIZED      FLUIDS. 

[The  lacteals  have  their  origin  in  the  villi  of  the  intestines,  while  the 
lymphatics  originate  throughout  the  body  in  the  various  tissues  and  organs 
of  which  it  is  composed. 

These  latter  vessels  are  arranged  in  a  superficial  and  deep  set ;  the 
superficial  running  underneath  the  skin,  or  under  the  membranous  coats, 
immediately  enveloping  the  organs  in  which  they  are  found,  while  the  deep 
lymphatics  usually  accompany  the  deep-seated  blood  vessels.  They 
usually  exceed  the  veins  in  number,  but  are  less  in  size,  and  anastomose 
more  frequently  than  the  accompanying  veins.  The  origin  of  the  lymph- 
atics may  be  either  superficial  or  deep :  in  the  first  mode,  they  usually  arise 
in  the  form  of  net-works,  or  plexuses,  out  of  which  single  vessels  emerge 
at  various  points,  and  proceed  directly  to  the  lymphatic  glands,  or  to  join 
larger  lymphatic  vessels. 

These  plexuses  consist  of  several  strata,  becoming  finer  as  they  approach 
the  surface,  both  in  the  calibre  of  the  vessels  and  closeness  of  reticulation. 
When  the  lymphatics  have  a  deep  origin,  their  precise  mode  is  not  so  easily 
made  out :  it  is  probably  the  same  as  when  they  arise  superficially. 

STRUCTURE. 

The  lymphatic  vessels,  in  their  structure  much  resembling  veins,  have 
thinner  and  more  delicate  coats ;  some  are  quite  transparent.* 

For  an  account  of  structure  of  lacteals,  see  page  492. 

The  medium-sized  and  larger  lymphatic  vessels,  according  to  Mr.  Lane,f 
have  three  coats ;  viz :  an  internal,  a  middle  or  fibrous,  and  an  external, 
one,  analogous  to  the  external  or  cellular  coat  of  the  blood-vessels. 

The  inner  tunic  is  thin,  transparent,  and  elastic,  but  less  elastic  than  the 
others,  being  the  first  to  give  way  when  the  vessel  is  unduly  distended  :  like 
the  blood-vessels,  it  is  lined  with  a  layer  of  scaly  or  tesselated  epithelium, 
as  in  the  blood-vessels.  The  middle  or  fibrous  coat  is  very  elastic,  and 
consists  of  longitudinal  fibres  having  the  characters  of  the  plain  involuntary 
muscular  fibres,  freely  mixed  with  fibres  of  cellular  tissue.  Herbst,  Henleij: 
and  others,  describe,  with  these  longitudinal  fibres,  others  of  transverse  and 
oblique  direction :  these  are  very  few  in  number,  the  great  majority  being 
longitudinal.  The  external  or  cellular  coat  is  elastic,  and  composed  of 
interlaced   fasciculi,  of  areolar  tissue,  mixed  with  some  elastic  fibres. 

The  lymphatics  receive  vasa  vasorum,  which  ramify  in  their  middle  and 
outer  coats;  nerves  distributed  to  them  have  not  yet  been  discovered,  al 
though  their  existence  has  been  inferred  on  physiological  grounds.  The} 
are  also  endowed  with  vital  contractility. 

*  Quain's  "Anatomy,"  5th  edition,  by  Sharpey  and  Quain. 
f  "Cyclop,  of  Anatomy  and  Physiology,"  art.  "Lym.  System." 
I  Henle,  "  Algemeine  Anatomie,"  Leipsic,  1841. 


THE   LYMPH   AND   THE   CHYLE.  77 

The  lymphatics  and  lacteals  are  supplied  with  valves  in  the  same  manner 
as  the  veins,  and  for  like  purposes.  They  usually  consist  of  two  semi-lunar 
folds,  but  variations  occasionally  occur.  They  are  altogether  wanting  in 
the  reticularly  arranged  vessels,  which  compose  the  plexuses  of  origin 
before  spoken  of;  but  where  they  exist,  they  follow  one  another  at  shorter 
intervals  than  in  the  veins. 

Mr.  T.  Wilkinson  King  (Guy's  Hospital  Reports,  April,  1840,)  has  calcu- 
lated the  entire  number  of  valves  in  the  lymphatic  system  at  30,000,  while 
the  veins  only  contain  about  5,000. 

The  lymphatics  of  fish  and  amphibia  are  usually  destitute  of  valves,  and 
may  be  injected  from  the  trunks :  in  birds,  valves  are  less  numerous  than 
in  the  lymphatics  of  the  mammiferous  animals. 

"  No  lymphatics  have  yet  been  traced  in  the  substance  of  the  brain  or  spinal  cord, 
though  they  exist  in  the  membranous  envelopes  of  these  parts,  nor  have  they  been 
detected  within  the  eye-ball,  or  in  the  placenta  or  foetal  envelopes.  Although  no 
absorbent  or  open  orifices  have  been  discovered  in  the  lacteals  or  lymphatics,  yet  it 
is  probable,  that  both  the  lymph  and  chyle  corpuscles  are  developed  as  cells  within 
the  vessels;  according  to  one  view,  these  corpuscles  of  lymph,  may  be  developed 
from  the  liquid  part  of  the  lymph,  which  serves  as  a  blastema.  In  this  case,  the 
nuclei  may  be  formed  by  aggregation  of  matter  round  nucleoli,  which  again  may  be 
derived  as  germs  from  other  cells;  or,  as  Henle  is  disposed  to  think,  two  or  more 
fat  particles  may  unite  to  form  a  nucleus ;  upon  another  view,  it  may  be  conceived 
that  these  corpuscles  are  formed  on  the  inner  surface  of  the  walls  of  their  containing 
vessels,  as  epithelium  or  mucous  corpuscles  are  produced  on  their  supporting  mem- 
brane, and  that  this  process  may  be  connected  with  the  absorption  of  lymph  or 
chyle  with  the  vessels,  in  the  same  manner  as  secretion  into  a  gland-duct,  or  other 
receptacle,  is  accompanied  by  the  formation  and  detachment  of  cells."* 

MANIPULATION- 

To  procure  lymph  and  chyle  quite  pure,  it  is  necessary  to  take  the  first 
from  the  lymphatic  glands,  and  the  second  from  the  lacteals  themselves. 
Wagner  has  found  dogs  the  best  subjects  for  such  experiments  in  compara- 
tive anatomy,  and  on  the  surface  of  the  liver  and  spleen,  are  commonly 
found  turgid  lymphatic  vessels,  from  which  pure  lymph  may  be  obtained. 
It  may  also  be  obtained  quite  pure  by  opening  the  thoracic  duct  of  an 
animal  that  has  fasted  for  some  time  before  being  killed. 

The  chemical  analysis  of  chyle  usually  quoted,  is  that  of  the  ass,  made 
by  Dr.  Rees,  and  of  the  cat,  made  by  Nasse. 

Dr.  Rees  has  examined  the  fluid  contained  in  the  thoracic  duct  of  a 
human  subject,  a  criminal,  an  hour  and  a  half  after  execution.  From  the 
small  quantity  of  food  taken  for  some  hours  before  death,  the  fluid  must 

*  Quain's  "Anatomy,"  by  Sharpey  and  Quain,  5th  edition. 


78  ORGANIZED      FLUIDS. 

have  consisted  principally  of  lymph.  It  had  a  milky  hue,  with  a  slight  tinge 
of  buff.  Its  analysis,  compared  with  that  of  the  chyle  of  the  ass,  given  in 
the  text,  shows  less  water,  more  albumen,  and  much  less  fat. 

The  chyle-corpuscles  are  most  numerous  in  the  chyle  taken  from  the 
mesenteric  glands. 

The  lymph  corpuscles,  though  closely  resembling  the  colourless  corpuscles 
of  the  blood,  hereafter  described,  are  rather  less  in  size,  and  not  so  uniformly 
round. 

The  globules  of  chyle  and  lymph,  also,  differ  in  structure  from  the  pale 
globules  of  blood  :  in  the  last,  two,  three  or  four  nuclei  are  easily  seen  when 
the  envelope  is  made  more  or  less  transparent,  by  acetic,  sulphureous,  citric, 
or  tartaric  acid.  But  globules  of  lymph  and  chyle,  like  the  nuclei  of  red 
corpuscles  of  blood,  are  only  rendered  more  distinct,  and  slightly  smaller  by 
any  of  these  acids ;  so  that  the  central  parts  present  no  regular  nuclei,  or 
divided  nucleus,  such  as  are  contained  in  pale  globules  of  blood.  In  the 
larger  lymphatics  and  thoracic  duct,  are  found  corpuscles  identical  in  size 
and  structure  to  the  pale  corpuscles  of  blood.  When  fresh,  the  corpuscles 
of  lymph  and  chyle  swell  on  being  mingled  with  pure  water,  as  does  the 
nucleus  of  blood  corpuscle.  Mixed  with  a  strong  alkali,  or  neutral  salt, 
the  globule  becomes  partially  dissolved,  mis-shapen,  or  fainter,  forming  a 
ropy  and  tenacious  compound  with  the  fluid.  According  to  Gulliver,  the 
average  measurements  of  the  corpuscles  of  lymph  and  chyle  are  the  same, 
viz :  -rJW  of  an  English  inch.     Mr.  Gulliver  measures  the  colourless  cor- 

4  6  0  0  o 

puscles  of  the  blood  3  ^V  o  °f  an  mc^'  or  about  1  larger  than  the  lymph  and 
chyle  corpuscles.* 

For  the  purposes  of  examination  and  study  of  the  corpuscles  of  lymph 
or  chyle,  it  is  necessary  to  place  a  very  small  drop  obtained  from  either  of 
the  sources  already  mentioned,  on  a  plain  glass  slide,  wiped  perfectly  clean 
and  dry,  and  cover  it  immediately  with  a  piece  of  thin  glass.  It  is  then 
ready  for  examination  with  a  ith  or  ith-inch  object  glass.  Sometimes  the 
corpuscles  will  be  better  observed  after  the  lymph  is  diluted  with  serum. 
After  examination  in  this  way,  the  different  reagents  may  be  applied,  by 
introducing  any  one  of  them  by  means  of  a  pipette  upon  the  edge  of  the  thin 
covering  glass  ;  by  means  of  capillary  attraction,  the  reagent  will  gradually 
insinuate  itself  under  the  glass,  and  its  effects  must  be  constantly  observed 
with  the  microscope. 

Plate  LXX.,  fig.  1,  exhibits  corpuscles  of  lymph. 
Fig.  2,  exhibits  corpuscles  of  chyle. 
Plate  LXXIII.,  fig.  1,  exhibits  a  lymphatic  gland,  and  lymphatic  vessels.] 

*  Hewson's  Worn       uied  by  Gulliver,  published  for  Sydenham  Society,  page  253. 


THE  BLOOD.  79 


ART.  II.  — THE  BLOOD. 

Of  all  the  fluids  in  the  animal  economy,  the  most  interesting  and 
the  most  important  is  the  Blood :  and  it  is  an  appreciation  of  this  fact 
which  has  led  to  the  concentration  upon  its  study,  in  times  past  as 
well  as  present,  of  the  powers  of  a  host  of  able  and  gifted  observers, 
whose  labours  have  not  been  without  their  reward. 

The  knowledge  of  this  fluid  acquired  by  the  early  physician  was 
of  a  very  limited  character,  it  being  confined  to  the  observance  of  a 
certain  number  of  external  and  obvious  appearances,  such  as  the 
colour,  consistence,  and  form  of  the  effused  blood.  Limited  as  this 
knowledge  was,  however,  compared  with  that  which,  in  our  favoured 
day,  we  enjoy,  it  was  not  without  its  practical  utility. 

More  recently,  the  chemist,  who  is  in  these  times  extending  in  all 
directions  so  rapidly  the  boundaries  of  his  domain,  has  cast  upon  this 
peculiar  portion  of  it  a  flood  of  light.  Who,  to  look  upon  a  dark  and 
discoloured  mass  of  blood,  could  imagine  that  the  magic  power  of 
chemistry  could  reveal  in  it  the  existence  of  not  less  than  forty  distinct 
and  essential  substances  ? 

Lastly,  the  micrographer,  with  zeal  unweariable,  has  even  outstripped 
the  progress  of  his  rival  the  chemist,  and  brought  to  light  results  of  the 
highest  importance.  It  is  these  results  that  in  this  work  we  have 
more  especially  to  consider. 

In  the  following  pages  we  shall  have  to  treat  of  the  blood  under 
various  aspects  and  conditions ;  we  shall  have  to  regard  it  alive  and 
dead,  circulating  within  its  vessels,  and  motionless  without  them ;  as 
a  fluid  and  as  a  solid;  healthy  and  diseased;  or,  in  other  words,  we 
shall  have  to  consider  the  blood  physiologically,  pathologically,  and 
anatomically. 

*  Those  who  wish  to  learn  the  comparative  size  of  the  hlood  corpuscles  in  the 
different  vertebrate  animals,  may  find  a  very  complete  table  of  their  measurements 
in  the  "Proceedings  of  the  Zoological  Society,  No.  152,"  carefully  prepared  by  Mr. 
Gulliver;  or  "  He wson's  Works,"  published  for  the  Sydenham  Society,  and  edited  by 
Mr.  George  Gulliver,  pp.  237 — 243:  or  "Gerber's  General  Anatomy,"  edited  by 
Gulliver — Appendix,  pp.  31 — 84. 


80  ORGANIZED     FLUIDS. 


The  blood  may  be  defined  as  an  elaborated  fluid,  having  usually 
a  specific  gravity  of  about  1055,  that  is,  heavier  than  water;  in 
mammalia  and  most  vertebrate  animals,  being  of  a  red  colour,  but 
colourless  in  the  invertebrata;*  circulating  in  distinct  sets  of  vessels, 
arteries,  and  veins;  holding  in  solution,  all  the  elements  of  the  animal 
fabric — fibrin,  albumen,  and  serum,  together  with  various  salts  and 
bases,  and  in  suspension,  myriads  of  solid  particles,  termed  globules. f 

The  blood  would  thus  appear  to  be  the  grand  supporter  and 
regenerator  of  the  system;  in  early  life,  supplying  the  materials 
necessary  for  the  development  of  the  frame,  and,  in  adult  existence, 
furnishing  those  required  for  its  maintainance :  hence  "the  blood" 
has  been  figuratively  called  "the  life." 

COAGULATION  OF  THE  BLOOD,  WITHOUT  THE  BODY. 

The  first  change  which  the  blood  undergoes  subsequent  to  its 
removal  from  the  body  consists  in  its  coagulation.  This  phenomenon 
has  been  denominated  emphatically,  "the  death  of  the  blood,"  because, 
when  it  has  once  occurred,  the  blood  is  thereby  rendered  unfit  to 
maintain  the  vital  functions,  and  there  is  no  known  power  which  can 
restore  to  it  that  faculty. 

Although  the  word  coagulation  is  usually  applied  generally  to  the 
blood,  yet  it  not  to  be  understood  that  the  whole  of  the  mass  of  that 
fluid  undergoes  the  change  of  condition  implied  by  the  term  coagula- 
tion, which  affects  but  a  single  element  of  the  blood,  viz :  the  fibrin. 

The  precise  circumstances  to  which  the  coagulation  of  the  blood  is 
due,  have  never  as  yet  been  satisfactorily  explained  and  determined. 
Some  have  conceived  that  it  resulted  from  the  escape  of  a  vital  air  or 
essence.  Much  has  been  said  and  written  upon  this  "vital  principle," 
and,  it  seems  to  me,  with  very  little  profit.     It  would  be  more  philo- 

*  Miiller  states  that  the  quantity  of  blood  in  the  system  varies  from  eight  to 
thirty  pounds,  and  Valentin  found  that  the  mean  quantity  of  Wood  in  the  male  adult, 
at  the  time  when  the  weight  of  the  body  is  greatest,  viz :  at  thirty  years,  is  about 
thirty-four  and  a  half  pounds,  and  in  the  adult  female,  at  fifty  years,  when  the  weight 
of  the  body  in  that  sex  is  at  its  maximum,  about  twenty-six  pounds.  According 
also  to  Miiller,  the  specific  gravity  of  the  blood  varies  from  1-527  to  1  *057 ;  arterial 
blood  is  lighter  than  venous. 

f  In  one  vertebrate  animal,  a  fish,  Branchiostoma  lubricum  Costa,  the  blood  is 
colourless,  and  in  the  most  of  Annelida  it  is  red ;  the  red  colour,  however,  exists  in 
the  liquor  sanguinis,  and  not  in  the  blood  corpuscles. 


THE     BLOOD.  81 

sophical,  I  think,  to  regard  animal  life  not  as  an  essence,  or  aether,  but 
as  the  complex  operation  of  nicely-adjusted  scientific  adaptations  and 
principles.  According  to  this  view,  the  human  frame  in  health  would 
be  comparable  (and  yet,  withal,  how  incomparable  is  it!)  to  a  finely- 
balanced  machine,  in  which  action  and  reaction  are  proportionate, 
and  in  disease  disproportionate,  the  injury  to  the  machine  being 
equivalent  to  the  disproportion  between  the  two  forces.* 

The  coagulation  of  the  blood,  in  some  degree,  doubtless  depends 
upon  the  operation  of  the  following  causes,  each  contributing  in  a 
greater  or  lesser  degree  to  the  result ;  namely,  the  cessation  of 
nervous  influence,  the  abstraction  of  caloric,  the  exercise  of  chemical 
affinity  between  the  particles  of  fibrin,  and,  lastly,  a  state  of  rest: 
between  motion  and  life  a  very  close  connexion  appears  to  exist.f 

Formation  of  the  Clot. 

A  portion  of  blood  having  been  abstracted  from  the  system,  and 
allowed  to  remain  for  a  few  minutes  in  a  state  of  quiesence,  in  a  basin 
or  other  suitable  vessel,  soon  manifests  a  change  of  condition.  This 
consists  in  the  separation  of  the  fibrin  and  globules  of  the  blood,  which 
go  to  form  the  clot,  from  the  serum,  which  holds  in  solution  the 
various  salts  of  the  blood.  In  this  way  a  rude  and  natural  analysis  is 
brought  about;  the  fibrin,  being  heavier  than  the  serum,  falls  to  the 
bottom,  and,  by  reason  of  its  coherence  and  contractility,  forms  a 
compact  mass  or  clot,  the  diameter  of  which  is  less  than  that  of  the 
vessel  in  which  it  is  contained ;  while  the  lighter  serum  floats  on  the 
top  and  in  the  space  around  the  clot. 

Now,  the  only  active  agent  in  this  change  in  the  arrangement  of 
the  different  constituents  of  the  blood,  is  the  fibrin;  and  although  the 
globules  of  the  blood  constitute  a  portion  of  the  clot,  yet  they  take  no 
direct  part  in  its  formation,  and  their  presence  in  it  is  thus  accounted 
for;  the  fibrin,  in  coagulating,  assumes  a  filamentous  and  reticular 
structure,  in  the  meshes  of  which  the  globules  become  entangled, 
and  thus  are  made  to  contribute  to  the  composition  of  the  clot,  the  bulk 
of  which  they  increase,  and  to  which  they  impart  the  red  colour. 

It  was  an  ancient  theory  that  the  clot  was  formed  solely  by  the 

*  It  is  hoped  that  the  preceding  brief  remarks  will  not  expose  the  writer  to  the 
charge  of  being  a  Materialist ;  between  animal  life  and  mind  an  essential  distinction 
exists. 

f  "  Fresh  blood,  if  exposed  to  a  very  low  temperature,  freezes,  and  may  in  that 
state  be  preserved,  so  as  to  be  still  susceptible  of  coagulation  when  thawed." — Mullek. 

6 


82  ORGANIZED     FLUIDS. 

union  of  the  globules  with  each  other.  The  fallacy  of  this  opinion  is 
easily  demonstrated  by  the  two  following  decisive  experiments: 

The  first  is  that  of  Muller,  on  the  blood  of  the  frog,  who  separated, 
by  means  of  a  filter,  the  globules  from  the  fibrin,  the  latter  still  form- 
ing a  clot,  although  deprived  of  the  globules.  This  experiment  is 
not,  however,  applicable  to  the  blood  of  man,  or  of  mammalia  in 
general,  the  globules  in  these  being  too  small  to  be  retained  by  the 
filter.  The  second  expedient  is,  however,  perfectly  suited  to  the 
human  blood.  It  is  well  known  that  if  blood,  immediately  after  its 
removal  from  the  body,  be  stirred  with  a  stick,  the  fibrin  will  adhere 
to  it  in  the  form  of  shreds ;  the  blood  being  defibrinated  by  this  means, 
the  globules  fall  to  the  bottom  of  the  basin  in  which  the  blood  is  con- 
tained, on  account  of  their  gravity;  but  they  do  not  cohere  so  as  to 
form  a  clot,  remaining  disconnected  and  loose. 

It  is  difficult  to  determine  the  exact  time  which  the  blood  takes  to 
coagulate,  because  this  coagulation  is  not  the  work  of  a  moment;  but, 
from  its  commencement  to  its  completion,  the  process  occupies 
usually  several  minutes.  The  first  evidence  of  the  formation  of  the 
clot,  is  the  appearance  of  a  thin  and  greenish  serum  on  the  surface  of 
the  blood,  in  which  may  be  seen  numerous  delicate  fibres,  the 
arrangement  of  which  may  be  compared  to  that  of  the  needle-like 
crystals  contained  in  the  solution  of  a  salt  in  which  crystallization  has 
commenced.  Estimating,  however,  the  coagulation  neither  from  its 
commencement  nor  from  the  complete  formation  and  consolidation 
of  the  clot,  but  from  the  mean  time  between  these  two  points,  it  will 
generally  be  found  that  healthy  blood  coagulates  in  from  fifteen  to 
twenty  minutes. 

In  diseased  states  of  the  system,  however,  the  time  occupied  in  the 
coagulation  of  the  blood,  or,  in  other  words,  in  the  formation  of  the 
crassamentum,  or  clot,  varies  very  considerably;  and  it  is  of  much 
practical  importance  that  the  principle  which  regulates  this  diversity 
should  be  clearly  understood. 

In  disorders  of  an  acute,  active,  or  sthenic  character,  in  which  the 
vital  energies  may  be  regarded  as  in  excess — as,  for  instance,  in 
inflammatory  affections,  in  pneumonia,  pleurisy,  acute  rheumatism, 
and  sanguineous  apoplexy :  in  febrile  states  of  the  system,  as  in  the 
commencement  of  some  fevers,  as  in  ague,  plethora,  and  as  in  utero- 
gestation — the  blood  takes  a  much  longer  time  than  ordinary  to 
coagulate,  no  traces  of  this  change  in  the  passage  of  the  blood  from  a 
fluid  to  a  solid  state  being  apparent  until  from  sixteen  to  twenty 


THE     BLOOD. 


83 


minutes  have  elapsed.  This  length  of  time  may  be  accounted  for, 
by  supposing  that,  in  the  affections  named,  the  blood  is  endowed  with 
a  higher  degree  of  vitality,  and  that  therefore  a  longer  period  is 
required  for  its  death  to  ensue ;  or,  in  other  words,  if  the  expression 
may  be  allowed,  that  the  blood  in  such  cases  dies  hard.  On  the  con- 
trary, in  disorders  of  a  chronic,  passive,  or  asthenic  character,  in  all 
of  which  there  is  deficiency  of  the  vital  powers — as  in  typhus,  anemia, 
chlorosis — the  blood  passes  to  a  solid  state  in  a  much  shorter  period 
than  ordinary,  even  in  from  five  to  ten  minutes.  In  these  cases  the 
vitality  of  the  blood  is  very  feeble,  and  it  may  be  said  to  die  easily. 
A  remarkable  difference  is  likewise  observable  in  the  characters  of  the 
clot  formed  in  the  two  classes  of  disorders  named ;  in  the  first  it  is 
firm,  and  well  defined;  in  the  second,  soft,  and  diffluent.*  To  this 
subject  we  shall  have  occasion  again  to  refer,  more  at  length. 

Fibrin,  if  left  at  rest  for  a  time,  undergoes  a  softening  process,  and 
breaks  up  into  an  extremely  minute  granular  substance.  This 
softening  of  the  fibrin  has  been  improperly  confounded  with  suppura- 
tion; the  softened  mass,  however,  may  be  distinguished  from  true 
pus  by  the  almost  complete  absence  of  pus  globules.  This  peculiar 
change  in  the  condition  of  the  fibrin  has  been  noticed  to  occur  both 
in  TDlood  contained  within  and  without  the  body,  and  large  softened 
clots  of  it  are  not  unfrequently  encountered  in  the  heart  after  death. 
The  process  always  commences  in  the  centre  of  these  clots. 

Formation  of  the  Buffy  Coat  of  the  Blood. 

Surmounting  the  coloured  portion  of  the  clot  is  observed,  in  blood 
taken  from  the  system  in  inflammatory  states,  a  yellowish-green 
stratum ;  this  constitutes  the  buffy  or  inflammatory  crust,  the  presence 
of  which  was  deemed  of  so  much  importance  by  the  ancient  physician, 
and  which  is  indeed  not  without  its  pathological  value.  This  crust 
consists  of  fibrin  deprived  of  the  red  globules  of  the  blood;  and  its 
mode  of  formation  is  thus  easily  and  satisfactorily  explained.  Of  the 
constituents  of  the  blood,  the  red  globules  are  the  heaviest;  now, 
supposing  that  no  solidification  of  any  one  element  were  to  take  place, 
these,  of  course,  would  always  be  found  occupying  the  lowest  position 
in  the  containing  vessel ;  the  fibrin  would  take  the  second  rank,  and  the 
serum  the  third :  but  such,  under  ordinary  circumstances,  not  being 

*  It  is  to  be  remarked,  that  the  clot  is  not  of  equal  density  throughout,  but  that 
its  lower  portion  is  invariably  softer  than  the  upper,  and  this  is  accounted  for  by  the 
fact  of  its  containing  less  fibrin. 


84  ORGANIZED     FLUIDS. 

the  case,  and  the  fibrin  coagulating  so  speedily,  the  globules  become 
entangled  in  its  meshes  before  they  have  had  sufficient  time  given 
them  to  enable  them  to  obey  fully  the  impulse  derived  from  their 
greater  specific  gravity ;  and  thus  no  crust  is  formed.  In  blood  drawn 
in  inflammations,  however,  this  coagulation,  as  already  stated,  pro- 
ceeds much  more  slowly;  and  thus  time  is  allowed  to  the  globules  to 
follow  this  impulse  of  the  law  of  gravity  to  such  an  extent,  as  that 
they  fall  a  certain  distance,  about  the  sixteenth  of  an  inch,  usually, 
below  the  surface  of  the  fibrin,  before  its  complete  coagulation  averts 
their  further  progress;  and  a  portion  of  which  is  thus  left  colourless, 
which  constitutes  the  buffy  and  so-called  inflammatory  crust  of  the 
blood.  But  there  are  other  considerations  to  which  it  is  necessary 
to  attend,  and  which  contribute  to  the  formation  of  the  buffy  coat. 

One  of  these  is  the  greater  relative  amount  of  fibrin  which 
inflammatory  blood  contains. 

A  second  is  the  increased  disposition,  first  pointed  out  by  Pro- 
fessor Nasse,  which  the  red  corpuscles  have  in  inflammatory  blood  to 
adhere  together  and  to  form  rolls,  and  the  consequence  of  which  is 
that  they  occupy  less  space  in  the  clot. 

A  third  additional  consideration,  to  which  it  is  necessary  to  attend, 
in  reference  to  the  formation  of  the  inflammatory  crust,  is  the  density 
of  the  blood,  which  bears  no  exact  relation  to  the  amount  of  fibrin, 
but  depends  rather  upon  the  quantity  of  albumen  which  it  contains.* 
The  greater  the  density  of  the  blood,  the  longer  would  the  globules 
take  to  subside  in  that  fluid ;  and  the  less  its  density,  the  shorter  would 
that  period  be.  Now,  inflammatory  blood  is  usually  of  high  density, 
while  with  that  of  feeble  vitality,  the  reverse  obtains.  Thus,  were  it 
not  for  the  fact,  that  in  blood  in  the  first  state,  coagulation  is  slow,  and 
in  the  second  quick,  the  blood  of  weak  vital  power  would  be  that  in 
which,  a  priori,  we  should  expect  to  see  the  buffy  coat  most  frequently 
formed ;  but  the  much  greater  rapidity  in  the  coagulation  of  the  blood 
more  than  counterbalances  the  effect  of  density. 

The  blood,  then,  may  be  so  dense,  that  although  at  the  same  time 
it  coagulates  very  slowly,  yet  no  inflammatory  crust  be  formed,  the 
patient  from  whom  the  blood  is  extracted  labouring  all  the  while 
under  severe  inflammation.  An  ignorance  of  this  fact  has  been  the 
source  of  many  great  and  perhaps  fatal  errors,  on  the  part  of  those 

*  It  has  been  remarked,  that  in  albuminuria,  in  which  a  considerable  portion  of 
the  albumen  of  the  system  passes  off  with  the  urine,  the  blood  possesses  a  very 
feeble  density. 


THE     BLOOD.  85 

physicians  who  have  been  used  to  regard  the  presence  of  the  buffy 
coat  as  an  undoubted  evidence  of  the  existence  of  inflammation,  and 
its  absence  as  indicating  immunity  therefrom.  It  has  been  remarked 
that,  in  the  first  bleedings  of  pnemonic  patients,  the  blood  often  wants 
the  buffy  coat;  this  is  attributed  to  its  greater  density,  and  which  is 
found,  to  diminish  with  each  succeeding  abstraction  of  blood;  so 
that  if  inflammation  be  present,  the  characteristic  coat  is  usually 
apparent  also  after  the  second  bleeding. 

The  conditions,  then,  favourable  to  the  formation  of  the  buffy  coat, 
are  a  mean  density  of  the  blood,  slow  coagulation,  excess  of  fibrin, 
and  increased  disposition  to  adherence  on  the  part  of  the  red  corpuscles. 

Other  circumstances  doubtless  exist,  which  in  a  minor  degree  affect 
the  formation  of  the  crust :  such  as  the  density  of  the  globules,  and 
the  qualities  of  the  fibrin  itself.  Into  these  it  is  unnecessary  to  enter, 
as  they  do  not  vitiate  the  accuracy  of  the  general  statements. 

The  Cupping  of  the   Clot. 

At  the  same  time  that  the  crassamentum  exhibits  the  buffy  coat,  the 
upper  surface  of  the  clot  is  very  generally  also  cupped.  This  cupping 
of  the  clot  arises  from  the  contraction  of  that  portion  of  the  fibrin 
which  constitutes  the  buffy  stratum,  and  which  contraction  operates 
with  greater  force  on  account  of  the  absence  in  it  of  the  red  corpuscles 
of  the  blood.  The  degree  to  which  the  clot  is  cupped,  therefore, 
probably  is  in  direct  relation  with  the  thickness  of  the  crust.  Its 
presence  was  also  regarded  as  an  indication  of  the  existence  of 
inflammation,  the  amount  of  cupping  denoting  the  extent  of  inflam- 
mation. This  sign  is  not,  however,  any  more  than  that  afforded  by 
the  buffy  coat,  to  be  considered  as  an  invariable  criterion  of  the 
existence  of  inflammation.* 

*  Professor  Nasse  has  pointed  out  a  mottled  appearance  which  is  frequently 
observed  to  precede  the  formation  of  the  buffy  coat,  and  the  existence  of  which  he 
states  to  be  quite  characteristic  of  inflammatory  blood.  This  appearance  is  produced 
in  the  following  manner :  after  the  lapse  of  a  minute  or  two,  a  peculiar  heaving 
motion  of  the  threads  or  rolls  formed  by  the  union  of  the  red  corpuscles  with  each 
other  is  observed  to  take  place ;  this  results  in  the  breaking  up  of  the  rolls,  the 
corpuscles  of  whieh  now  collect  into  masses,  leaving,  however,  intervals  between 
them,  and  which  become  filled  with  fibrin ;  now,  it  is  the  contrast  in  colour  between 
this  fibrin  and  the  masses  of  red  corpuscles  which  occasions  the  blood  in  coagulating 
to  assume  the  mottled  aspect  referred  to. 


86  ORGANIZED     FLUIDS. 

COAGULATION    OF    THE    BLOOD,    IN    THE    VESSELS     AFTER    DEATH. 

The  coagulation,  or  death,  which  we  have  described  as  occurring 
in  blood  abstracted  from  the  system  by  venesection,  takes  place  like- 
wise— the  vital  influence  which  maintains  the  circulation  being 
removed — in  that  which  is  still  contained  within  the  vessels  of  the 
body,  although  in  a  manner  less  marked  and  appreciable. 

As  also  in  the  case  of  the  blood  withdrawn  from  the  system,  the 
time  occupied  in  the  coagulation  of  that  which  is  still  enclosed  in  its 
own  proper  vessels,  varies  very  considerably.  This  difference 
depends  partly  upon  the  circumstances  under  which  the  patient  has 
died,  whether  he  has  been  exhausted  or  not  by  a  previous  long  and 
wasting  illness,  and  partly  upon  temperature  and,  perhaps,  certain 
electric  states  of  the  atmosphere.  In  all  instances,  however,  a  much 
longer  period  is  required  for  the  production  of  coagulation  in  blood 
not  removed  from  the  body,  than  in  that  which  has  been  withdrawn 
by  bleeding;  this  change  in  its  condition  being  seldom  effected,  in  the 
former  instance,  in  a  shorter  period  than  from  twelve  to  twenty-four 
hours  subsequent  to  decease ;  although  occasionally,  but  rarely,  it  may 
occur  at  periods  either  earlier  or  later  than  those  named. 

Signs  of  Death. — It  has  already  been  stated,  that  blood  once  coag- 
ulated is  rendered  unfit  for  the  purposes  of  life,  and  that  no  known 
means  exist  capable  of  restoring  to  coagulated  blood  its  fluid  state,  so 
as  to  render  it  once  again  suited  to  play  its  part  in  the  maintenance 
of  the  vital  functions.  The  accuracy  of  these  statements  is  attested 
by  physiology,  which  demonstrates  to  us  that  a  fluid  condition  is 
necessary  to  the  blood,  for  the  correct  performance  of  its  allotted 
functions.  It  follows,  then,  from  the  foregoing,  that  a  coagulated 
state  of  the  blood,  not  in  a  single  vessel  indeed,  but  in  the  vessels  of 
the  system  generally,  affords  a  certain  indication  that  death  has 
occurred,  and  that  therefore  a  return  to  life  has  become  impossible. 

It  has  ever  been  an  object  of  the  highest  importance  to  distinguish 
real  from  apparent  death;  and  anxious  searches  have  been  instituted 
in  the  hope  of  discovering  some  certain  sign  whereby  the  occurrence 
of  death  is  at  once  signalized.  Hitherto  this  inquiry  has  been  unsuc- 
cessful; and  it  could  hardly  have  been  otherwise;  for  before  the 
physiologist  will  be  able  to  determine  the  precise  moment  when  life 
ceases,  and  death  begins,  he  must  know  in  what  the  life  consists,  for 
death  is  but  the  negation  of  life.  It  is  probable  that  the  mystery  of 
life  will  never  be  revealed  to  man ;  if,  indeed,  it  be  any  thing  more 


THE     BLOOD.  87 

than,  as  already  hinted,  the  result  of  the  combined  operation  of  vari- 
ous chemical  and  physical  laws  appertaining  to  matter. 

Although  no  one  single  sign  has  hitherto  been  discovered  indicative 
of  death  at  the  moment  of  its  occurrence,  yet  several  appearances 
have  been  remarked  some  time  after  death,  all  of  which  are  of  more 
or  less  value  in  determining  so  important  a  point.  Independently  of 
the  cessation  of  respiration  and  circulation,  the  presence  of  muscular 
rigidity,  some  other  changes  have  been  noticed  to  occur  in  different 
parts  of  the  human  body  soon  after  the  extinction  of  life;  as,  for 
instance,  in  the  eye,  and  in  the  skin:  these  are  mostly,  however, 
symptomatic  of  incipient  decomposition,  and  the  time  of  their  acces- 
sion is  very  uncertain:  they  likewise  affect  parts,  the  integrity  of 
which  is  not  essential  to  life.  A  fluid  state  of  the  blood,  on  the  con- 
trary, has  been  shown  to  be  indispensable  to  life;  so  that  the  change 
which  it  undergoes  in  the  vessels  of  the  body  so  quickly  after  death, 
may  be  employed  with  much  advantage  and  certainty  in  determining, 
in  doubtful  cases,  whether  life  has  become  extinct  or  not. 

It  is  by  no  means  difficult  to  establish  the  fact  of  the  coagulation 
of  the  blood  in  the  vessels  after  death.  If  a  vein  be  opened,  as  in  the 
ordinary  operation  of  bleeding,  in  a  person  who  has  just  died,  the 
blood  will  issue  in  a  fluid  state,  as  in  life ;  but  it  will  not  leap  forth  in 
a  stream.  If  a  little  of  the  blood,  thus  procured,  be  preserved  in  a 
small  glass,  we  shall  soon  remark  the  occurrence  of  coagulation  in  it, 
from  which  we  shall  know  that  the  fibrin  within  the  vessels  has  not 
as  yet  assumed  a  solid  form.  If  we  repeat  this  operation  at  the  end 
of  about  eighteen  hours,  we  shall  obtain  only  a  small  quantity  of  red- 
dish serum,  in  which,  on  being  set  aside  for  a  time,  no  crassamentum 
will  be  found,  the  only  change  occurring  in  this  serum  consisting  in 
the  subsidence  of  the  few  red  globules  which  were  previously  sus- 
pended in  it,  and  which  now  form,  at  the  bottom  of  the  glass,  a  loose 
and  powdery  mass.  By  this  experiment,  which  may  be  repeated  on 
several  veins,  and  even  on  an  artery,  we  have  clearly  established  the 
fact  of  the  coagulation  of  the  blood  within  the  vessels  of  the  body, 
and  therefore  have  ascertained,  in  a  manner  the  most  satisfactory, 
that  life  is  extinct. 

In  some  instances,  the  blood  is  said  to  remain  fluid  after  death: 
this  statement  is  not  strictly  correct,  as  a  careful  examination  of  such 
blood  will  always  lead  to  the  detection  of  some  traces  of  coagulation. 
To  the  subject  of  the  fluid  condition  of  the  blood  after  death,  we  shall 
have  hereafter  to  return,  in  treating  of  the  pathology  of  the  blood. 


88  ORGANIZED     FLUIDS. 

When  it  is  recollected  that  the  heat  of  some  climates,  and  the  laws 
and  usages  of  other  countries,  compel  the  interment  of  the  dead  a 
very  few  hours  after  decease,  the  importance  of  this  inquiry  will 
become  apparent ;  and  the  value  of  any  sign  which  more  certainly 
indicates  death  than  those  usually  relied  upon  in  determining  this 
question,  will  be  more  fully  appreciated. 

It  cannot  be  doubted  but  that,  from  the  insufficient  nature  of  the 
signs  of  death  usually  regarded  as  decisive,  premature  interment  does 
occasionally  take  place ;  and  it  is  probable  that  this  occurrence  is  far 
less  unfrequent  than  is  generally  supposed,  and  that  for  each  discov- 
ered case,  a  hundred  occur  in  which  the  fatal  mistake  is  never  brought 
to  light,  it  being  buried  with  the  victim  of  either  ignorance  or  care- 
lessness.* 

We  have  now  to  proceed  to  the  anatomical  consideration  of  the 
blood ;  we  have  to  pass  to  the  description  of  the  solid  constituents  of 
that  fluid,  the  globules ;  to  describe  their  different  kinds,  their  form, 
their  dimensions  and  their  structure ;  their  origin,  their  development, 
and  their  destination,  their  properties,  and  their  uses. 

THE  GLOBULES  OF  THE  BLOOD. 

The  blood  is  not  an  homogeneous  fluid,  but  holds  in  suspension 
throughout  its  substance  a  number  of  solid  particles,  termed  globules. 
These  serve  to  indicate  to  the  eye  the  motion  of  the  blood ;  and  were 
it  not  for  their  presence,  we  should  be  unable  to  establish,  micro- 
scopically, the  fact  of  the  existence  of  a  circulation,  to  mark  its  course, 
and  to  estimate  the  relative  speed  of  the  current  in  arteries  and  veins 
under  different  circumstances. 

These  globules  are  so  abundant  in  the  blood,  that  a  single  drop 
contains  very  many  thousands  of  them,  and  yet  they  are  not  so  minute 
but  that  their  form,  size,  and  structure,  with  good  microscopes,  can 
be  clearly  ascertained  and  defined.  They  are  not  all  of  one  kind,  but 
three  different  descriptions  have  been  detected — the  red  globules,  the 
white,  and  certain  smaller  particles,  termed  molecules.  We  shall 
take  each  of  them  in  order;  and  notice,  in  the  first  place,  the  red 
globules,  f 

*  The  coagulation  of  the  blood  may  he  retarded  or  altogether  prevented  by  its 
admixture  with  various  saline  matters :  to  this  point  we  shall  have  occasion  to  refer 
more  fully  hereafter. 

f  Malpighi  first  signalized  the  existence  of  the  red  globules  in  the  blood,  so  far 
back  as  1665:  he  regarded  them  as  of  an  oily  nature.    The  words  in  which  this  dis~ 


THE     BLOOD.  89 


THE    RED    GLOBULES. 


The  number  of  red  globules  existing  in  the  blood  surpasses  by  many- 
times  that  of  the  white.  To  the  sight,  when  seen  circulating  in  this 
fluid,  they  appear  to  constitute  almost  the  entire  of  its  bulk.  We 
shall  now  have  to  consider  their  form,  the  size,  the  structure,  and  the 
properties  by  which  they  are  characterized. 

Form. — In  man,  and  in  most  mammalia,  the  red  blood  corpuscles 
are  of  a  circular,  but  flattened,  form,  with  rounded  edges,  and  a  central 
depression  on  each  surface,  the  depth  of  which  varies  according  to 
the  amount  of  the  contents  of  each  globule.*  Such  is  the  normal  form 
of  the  blood  discs,  or  the  shape  proper  to  them  while  circulating  in 
the  blood  of  an  adult.  (See  Plate  I.  fig.  1.)  In  that  of  the  embryo, 
the  depression  is  wanting,  and  the  globules  are  simply  lenticular. f 

The  blood  globules,  however,  like  all  minute  vesicles,  possess  the 
properties  of  endosmosis  and  exosmosis.  These  principles  depend  for 
their  operation  upon  the  different  relative  density  of  two  fluids,  the 
one  external  to  the  vesicle,  the  other  internal.  When  these  two  fluids 
are  of  equal  density,  then  no  change  in  the  normal  form  of  the  vesicles 
occurs :  when,  however,  the  internal  fluid  is  of  greater  density  than 
the  external,  then  an  alteration  of  shape  does  take  place ;  endosmosis 
ensues,  in  which  phenomenon  a  portion  of  the  liquid  without  the 
vesicle  passes  through  its  investing  membrane,  and  thus  distends  and 
modifies  its  form.  Lastly,  when  a  reverse  disposition  of  the  fluids 
exists,  a  contrary  effect  becomes  manifested;  exosmosis  is  the  result; 
this  implies  the  escape  of  a  portion  of  the  contents  of  the  vesicle  into 
the  medium  which  surrounds  and  envelopes  it.     The  operation  of 

covery  was  recorded  were  as  follow:  "Sanguineum  nempe  vas  in  omento  hystricis . . . 
in  quo  globuli  pinguedinis  propria  figura  terminati  rubescentes  et  corallorum  rubrorum 
vulgo  coronam  Eemulantes . . ." — De  Omento  et  adiposis  Ductibus.  Opera  omnia. 
Lond.  1686. 

Leeuwenhoek  was,  however,  the  first  observer  who  distinctly  described  the  blood 
globules  in  the  different  classes  of  animals:  this  he  did  in  1673.  These  historical 
reminiscences  are  not  without  their  interest,  and  further  references  of  this  kind  will  be 
introduced  in  the  course  of  the  work. 

*  The  central  depression  was  first  noticed  by  Dr.  Young.  The  flattened  form  with 
the  central  depression  on  each  surface,  and  of  which  a  bi-concave  lens  would  form  an 
apt  illustration,  is  that  which  any  vesicle  partially  emptied  of  its  contents  would 
assume. 

f  Hewson  figured  the  difference  in  the  form  of  the  blood  globule  in  the  embryo, 
and  in  the  adult,  in  the  common  domestic  fowl,  and  in  the  viper. 


90  ORGANIZED     FLUIDS. 

these  principles  is  beautifully  seen,  not  merely  in  the  blood  globules, 
but  more  especially  in  those  exquisitely  delicate  formations,  the  pollen 
granules. 

■  Between  the  density  of  the  liquid  contained  within  the  red  globules, 
and  that  of  the  liquor  sanguinis,  in  states  of  health,  a  nice  adaptation 
or  harmony  exists,  whereby  these  globules  are  enabled  to  retain  their 
peculiar  form.  There  is,  however,  scarcely  any  other  fluid  which 
can  be  applied  to  the  globules  which  does  not,  more  or  less,  affect  their 
shape,  most  of  the  reagents  employed  in  their  examination  rendering 
them  spherical.     (See  plate  I.  fig.  3.) 

From  the  preceding  observations,  therefore,  it  follows  that  the  red 
globules,  to  be  seen  in  their  normal  condition,  should  be  examined 
while  still  floating  in  the  serum :  they  are  best  obtained  by  pricking 
the  finger  with  a  needle  or  lancet. 

Usually,  when  the  microscope  is  brought  to  bear  upon  the  object- 
glass,  the  globules  are  seen  to  be  scattered  irregularly  over  its  surface, 
the  majority  of  them  presenting  their  entire  disc  to  view,  others  lying 
obliquely,  so  as  to  render  apparent  the  central  depression,  and  others 
again  exhibiting  their  thin  edges,  (See  Plate  I.  fig.  1.)  Not  unfre- 
quently,  however,  a  number  of  corpuscles  unite  together  by  their  flat 
surfaces,  so  as  to  form  little  threads,  comparable  to  strings  of  beads, 
or  of  coins,  which  are  more  or  less  curved,  and  in  which  the  lines  of 
junction  between  the  corpulscles  are  plainly  visible.  These  strings 
of  compressed  globules  bear  also  a  close  resemblance  to  an  Oscillatoria, 
and  a  still  closer  likeness  to  the  plant  described  in  the  history  of  the 
British  Fresh- water  Algae,  under  the  name  of  Hcematococcus  Hooker- 
iana.  (See  Plate  I.  fig.  4.)  The  cause  which  determines  this  union 
of  the  cells  still  requires  to  be  explained,  and  would  seem  to  be  referable 
to  a  mutual  attraction  exerted  by  the  globules  on  each  other.  Andral 
asserts  that  when  the  fibrin  of  the  blood  is  abstracted,  they  do  not 
thus  cohere.  Professor  Nasse,  as  already  remarked,  states  that  this 
disposition  on  the  part  of  the  red  corpuscles  to  unite  together  and  form 
rolls  (as  of  miniature  money  in  appearance),  is  increased  in  inflamma- 
tory blood.  The  union  does  not,  however,  last  long;  a  heaving  to  and 
fro  of  the  strings  of  corpuscles  soon  taking  place,  and  which  terminates 
in  their  disruption.* 

*  In  reptiles,  birds,  and  fishes,  the  red  globules  are  elliptical,  a  form  possessed  also 
by  some  few  mammalia,  chiefly  of  the  family  CamelidcE.  This  fact  was  discovered 
by  Mandl,  in  the  dromedary  and  paco  ;  and  subsequently  by  Gulliver,  in  the  vicugna 
and  llama.  The  oval  globules  of  these  animals,  however,  could  not  be  confounded 
with  those  of  reptiles,  buds,  and  fishes,  than  the  corpuscles  of  which  they  are  so 


THEBLOOD.  91 

Size. — The  size  of  the  red  corpuscles  of  the  blood,  although  more 
uniform  than  that  of  the  white,  is  nevertheless  subject  to  considerable 
variation.  Thus,  the  globules  contained  in  a  single  drop  of  blood  are 
not  all  of  the  same  dimensions,  but  vary  much.  These  variations  are, 
however,  confined  within  certain  limits:  the  usual  measurement  in  the 
human  subject  is  estimated  at  about  the  3  5V0  °f  and  inch;  but,  occa- 
sionally globules  are  met  with  not  exceeding  the  TIj T ;  and,  again, 
others  are  encountered  of  the  magnitude  of  the  32V  9  °f  an  mcn  >  tnese 
are,  however,  the  extreme  sizes  which  present  themselves.*  The 
difference  in  the  size  of  the  red  corpuscles,  which  has  been  indicated, 
is  a  character  common  to  them  in  the  blood  of  all  persons,  and  at 
every  age.  Another  variation  as  to  size  exists,  which  is,  that  the 
corpuscles  are  larger  in  the  embryonic  and  fetal  than  they  are  in 
adult  existence. f  This  observation  is  important,  inasmuch  as  it  seems 
to  pi'ove  that  the  blood  does  not  pass  directly  from  the  maternal  system 
into  the  fetal  circulation,  but  that  the  corpuscles  are  formed  independ- 
ently in  the  fetus.  In  states  of  disease,  also,  it  has  been  remarked  by 
Mr.  Gulliver  that  there  is  even  a  still  greater  want  of  uniformity  in 
the  measurements  presented  by  the  red  corpuscles. 

much  smaller,  and,  further,  are  destitute  of  the  central  nucleus,  which  characterizes 
the  blood  globules  of  all  the  vertebrata,the  mammalia  alone  excepted.  The  long 
diameter  of  the  blood  corpuscles  of  the  dromedary,  Mr.  Gulliver  states  to  be  the 
s^sx  of  an  inch,  and  its  short  the  j^y ;  the  first  of  these  measurements  exceeds  but 
little  the  diameter  of  the  human  blood  corpuscles. 

Among  fishes,  one  exception  to  the  usual  oval  form  of  the  blood  corpuscle  has 
been  met  with:  this  occurs  in  the  lamprey,  the  blood  disc  of  which  Professor  Rudolph 
Wagner  observed  to  be  circular ;  in  form  then  the  blood  corpuscles  of  the  lamprey 
agrees  with  that  of  the  mammalia,  but  in  the  presence  of  a  nucleus,  the  existence  of 
which  has  been  recently  ascertained  by  Mr.  T.  W.  Jones,  it  corresponds  with  the 
structure  of  the  blood  discs  of  other  fishes. 

*  The  first  measurement  given  is  that  which  is  usually  adopted  by  writers ;  the 
last  two  are  those  made  by  Mr.  Bowerbank  for  Mr.  Owen,  and  which  are  to  be  found 
in  the  latter  gentleman's  paper  on  the  Comparative  Anatomy  of  the  Blood  Discs, 
inserted  in  the  Lond.  Med.  Gazette  for  1839.  The  measurements  which  I  have  made 
of  the  human  blood  corpuscle  do  not  accord  with  those  which  are  generally  regarded 
as  correct :  thus  I  find  the  average  diameter  of  the  blood  globule  of  man  to  be,  when 
examined  in  the  serum  of  the  blood,  about  the  -g-gVn  °f  an  inch>  an(i  m  water  in  which 
the  corpuscles  are  smaller,  as  a  necessary  consequence  of  the  change  of  form,  the 
3^.  The  micrometer  employed  by  me  is  a  glass  one,  precisely  similar  to  that 
made  use  of  by  Mr.  Gulliver,  being  furnished  to  me  by  the  same  eminent  optician, 
Mr.  Ross,  from  whom  his  own  was  obtained. 

f  This  is  the  opinion  of  Hewson,  Provost,  and  Gulliver,  and  I  have  myself  to  some 
extent  confirmed  its  accuracy. 


92  ORGANIZED     FLUIDS. 

A  careful  examination  of  the  elaborate  tables  of  Mr.  Gulliver  on 
the  measurements  of  the  blood  corpuscles,  appended  to  the  translation 
of  Gerber's  Minute  Anatomy  tends  to  show  that  a  general  though  not 
a  very  close  or  uniform  relation,  exists  between  the  size  of  the  blood 
corpuscles  among  the  mammalia,  and  that  of  the  animal  from  which 
they  proceed.  These  tables  furnish  more  evidence  in  favour  of  this 
co-relation  than  they  do  in  support  of  the  assertion  that  has  been  made, 
that  the  dimensions  of  the  corpuscle  depend  upon  the  nature  of  the 
food.  It  would  appear,  however,  nevertheless,  that  the  corpuscles  of 
omnivora  are  usually  larger  than  those  of  carnivora,  and  these,  again, 
larger  than  those  of  herbivora*  In  a  perfectly  natural  family  of 
mammalia,  as  the  rodents  or  the  ruminants,  there  is  also  an  obvious 
relation  between  the  size  of  the  corpusucle  and  that  of  the  animal. 
Gerber  states  that  there  is  an  exact  relation  between  the  size  of  the 
blood  globules  and  that  of  the  smallest  capillaries.  This  observation 
is  doubtless  strictly  correct. 

Structure. — Much  diversity  of  opinion  has,  until  recently,  prevailed, 
and  does  still  obtain,  although  to  a  less  extent,  in  reference  to  the 
intimate  structure  of  the  red  globule.  This  diversity  has  arisen  partly 
from  the  imperfections  of  the  earlier  microscopic  instruments  employed 
in  the  investigation,  and  in  part  is  due  to  the  different  circumstances 
in  which  observers  have  examined  the  blood  corpuscle.  Thus,  one 
micrographer  would  make  his  observations  upon  it  in  one  fluid,  and 
another  in  some  other  medium,  opposite  results  and  conclusions  not 
unfrequently  being  the  results  of  such  uncertain  proceedings.  These 
discrepancies  it  will  be  the  writer's  endeavour,  as  far  as  possible,  to 
reconcile  with  each  other,  as  well  as  to  point  out  those  observations 
which  are  entitled  to  our  implicit  belief,  and  those  which  yet  require 
confirmation.  This  being  done,  we  shall  be  in  a  position  to  form 
some  certain  conclusions.  The  earlier  microscopic  observers  believed, 
almost  without  exception,  in  the  existence  of  a  nucleus  in  the  centre 
of  each  blood  corpuscle.     Into  this  belief  they  were  no  doubt  led 

*  The  largest  globules  which  have  as  yet  been  discovered,  are  those  of  the 
elephant;  the  next  in  size,  those  of  the  capybara  and  rhinoceros;  the  smallest, 
according  to  the  observations  of  Mr.  Gulliver,  are  those  of  the  napu  musk-deer.  The 
corpuscles  of  the  blood  of  the  goat  were  formerly  considered  to  be  the  smallest. 
The  following  are  the  dimensions  given  by  Mr.  Gulliver  of  some  of  the  animals 
above  named.  Diameter  of  corpuscle  of  the  elephant,  the  -^  -$  of  an  inch ;  of  capybara 
the  32Y3  5  of  goat,  the  -5^;  and  of  napu  musk-deer  j^^rs-  The  white  corpuscles 
of  the  musk-deer  are  as  large  as  those  of  a  man;  a  proof  that  the  red  corpuscles  are 
not  formed,  as  many  suppose,  out  of  the  colourless  blood  globules.     (See  the  figs.) 


THE     BLOOD.  93 

more  from  analogy  than  from  actual  observation.  Now,  analogy, 
although  frequently  useful  in  the  elucidation  of  obscure  points,  affords 
in  the  present  instance  but  negative  and  uncertain  evidence.  In  the 
elliptical  blood  discs  of  reptiles,  birds,  and  fishes,  a  solid  granular 
nucleus  does  undoubtedly  exist;  but  the  best  optical  instruments,  in 
the  hands  of  the  most  skilful  recent  micrographers,  aided  by  the  appli- 
cation of  a  variety  of  reagents,  have  failed,  utterly,  in  detecting  the 
presence  of  a  similar  structure  in  the  blood  globule  of  the  human 
subject  in  particular,  and  of  mammalia  in  general.  I  therefore  do  not 
hesitate  to  join  my  opinion  to  that  of  those  observers  who  deny  the 
existence  of  a  nucleus  in  the  blood  discs  of  man  and  mammalia.* 

The  appearance  of  a  nucleus  is,  indeed,  occasionally  presented; 
but  this  appearance  has  been  wrongly  interpreted.  An  internal  small 
ring,  under  favourable  circumstances,  may  be  seen  in  the  centre  of 
each  blood  corpuscle :  this  ring  is  occasioned  by  the  central  depression, 
the  outer  margin  of  which  it  describes;  and  it  was  the  observance 
of  it  that  gave  to  Delia  Torre  the  erroneous  impression,  that  each 
globule  had  a  central  perforation,  and  therefore  was  of  an  annular  form ; 
and  further,  probably  induced  Dr.  Martin  Barry  to  describe  it  as  a  fibre. 

The  very  existence,  on  both  surfaces  of  the  blood  disc,  of  a  deep 
central  depression,  together  with  its  little  thickness,  almost  preclude 
the  possibility  of  the  presence  of  a  nucleus. 

An  endeavour  to  account  for  the  absence  of  a  nucleus  in  the  blood 
corpuscle  of  the  human  adult  has  been  made  by  supposing  that  it  does 
really  exist  in  the  blood  of  the  embryo.  The  answer  to  this  supposi- 
tion is,  that  no  nucleus  is  to  be  found  in  embryonic  blood,  and  that  if 
it  were,  it  would  be  no  reason  why  the  nucleus  should  not  also  be 
met  with  in  the  blood  of  the  adult,  seeing  that  the  blood  disc  is  not  a 
permanent  structure,  as  an  eye  or  a  limb,  but  one  which  is  perpetually 
subject  to  destruction  and  renewal. 

Having  then  arrived  at  the  conclusion  that  no  nucleus  exists  in 
the  blood  corpuscle  of  man,  we  have  now  to  ask  ourselves  the  ques- 
tion, what,  then,  is  really  the  constitution  of  the  red  blood  globule? 

Some  observers  have  compared  it  to  a  vesicle.  This  definition 
does  not  seem  to  be  altogether  satisfactory;  for  although  each 
corpuscle  possesses  the  endosmotic  properties  common  to  a  vesicle, 

*  Among  those  who  have  asserted  their  belief  in  the  presence  of  a  nucleus,  may- 
be mentioned  Hewson,  Miiller,  Gerber,  Mandl,  Barry,  Wagner,  Rees,  Lane,  and 
Addison ;  and  of  those  who  have  held  a  contrary  opinion,  Magendie,  Hodgkin,  Liston, 
Young,  Quekett,  Gulliver,  Lambotte,  Owen,  and  Donne. 


94  ORGANIZED     FLUIDS. 

no  membrane,  apart  from  the  general  substance  of  the  globule,  (I 
speak  more  particularly  of  the  human  blood  disc,)  has  been  demon- 
strated as  belonsinar  to  it. 

Each  globule  in  man  may  therefore  be  defined  to  be  an  organism 
of  a  definite  form  and  homogeneous  structure,  composed  chiefly  of  the 
proteine  compound  globuline,  which  resembles  albumen  very  closely 
in  its  properties ;  its  substance  externally  being  more  dense  than 
internally,  it  being  endowed  with  great  plastic  properties,  and,  finally, 
being  the  seat  of  the  colouring  matter  of  the  blood. 

The  extent  to  which  the  red  globule  is  capable  of  altering  its  form, 
is  truly  remarkable.  If  it  be  observed  during  circulation,  it  will 
be  seen  to  undergo  an  endless  variety  of  shapes,  by  which  it 
accommodates  itself  to  the  space  through  which  it  has  to  traverse, 
and  to  the  pressure  of  the  surrounding  globules.  The  form  thus 
impressed  upon  it  is  not,  however,  permanent;  for  as  soon  as  the 
pressure  is  removed,  it  again  instantaneously  resumes  its  normal 
proportions.  On  the  field  of  the  microscope,  however,  the  corpuscles 
may  be  so  far  put  out  of  form,  as  to  be  incapable  of  restoration  to 
their  original  shape. 

Some  observers  have  assigned  to  the  red  globule  a  compound 
cellular  structure,  comparing  it  to  a  mulberry.  It  need  scarcely  be 
said  that  such  a  structure  does  not  really  belong  to  it.  A  puckered 
or  irregular  outline  is  not  unfrequently  presented  by  many  globules; 
this  is  due  sometimes  to  evaporation,  and  then  arises  from  the  presence 
around  the  margin  of  the  disc,  and  occasionally  over  the  whole 
surface,  of  minute  bubbles  of  air;*  and  at  other  times  it  is  the  result 
of  commencing  decomposition,  or  the  application  of  some  special 
reagent,  as  a  solution  of  salt,  in  which  cases  a  true  change  in  the  form, 
but  not  in  the  structure  of  the  globule,  does  really  occur;  its  outline 
becomes  irregular,  and  the  surface  presents  numerous  short  and  obtuse 
points  or  spines.f  Globules  in  this  state  bear  some  resemblance  to  the 
pollen  granules  of  the  order  Compositce.X     (See  Plate  I- fig.  5.) 

*  This  vesiculated  appearance  of  the  blood  corpuscles  may  be  produced  at  once 
by  pressure. 

f  Mr.  Wharton  Jones  says,  "  the  granulated  appearance "  seems  to  be  owing  to  a 
contraction  of  the  inner  and  a  wrinkling  of  the  outer  of  the  two  layers  of  wnich  he 
conceives  the  wall  of  the  corpuscle  to  be  formed. 

I  The  opinions  promulgated  by  some  observers  in  reference  to  the  intimate  struc- 
ture of  the  blood  corpuscles  are  singular,  and  are  rendered  interesting  mainly  by 
reason  of  the  ingenuity  of  the  views  expressed.    Mr.  Addison  remarks:1  "Blood 

1  Experimental  Researches,  pp.  236,  237.    Transactions  of  Prov.  Med.  and  Surg.  Association. 


THEBLOOD.  95 

Colour. — The  hcematine,  or  colouring  matter  of  the  blood,  seems 
in  the  red  corpuscle  of  the  mammalia  to  be  diffused  generally 
throughout  its  substance;  in  the  oviparous  vertebrata,  however,  it  is 
confined  to  that  portion  of  each  corpuscle  which  corresponds  with 

corpuscles,  therefore,  appear  to  consist  of  two  elastic  vesicles,  one  within  the  other, 
and  to  possess  the  following  structure:  1st,  an  external  and  highly-elastic  tunic, 
forming  the  outer  vesicle;  2d,  an  inner  elastic  tunic,  forming  the  interior  vesicle; 
3d,  a  coloured  matter,  occupying  the  space  between  the  two  tunics;  and  4th, 
a  peculiar  matter,  forming  the  central  portion  of  the  corpuscle."  Mr.  Wharton 
Jones  l  ascribes  a  somewhat  similar  constitution  to  the  blood  corpuscle :  "  The  thick 
wall  of  red  corpuscle,"  he  says,  "consists  of  two  layers.  The  outer  is  transparent, 
colourless,  structureless,  and  resisting,  and  constitutes  about  one-half  of  the  whole 
thickness  of  the  wall.  The  inner  layer  is  softer  and  less  resisting;  and  is  that 
which  is  the  seat  of  the  colouring  matter."  Dr.  G.  O.  Rees  and  Mr.  Lane  2  describe 
the  blood  corpules  as  containing  a  fluid,  and  provided  with  a  nucleus  composed  of  a 
thin  and  colourless  substance.  The  views  of  Dr.  Martin  Barry  are,  however,  the 
most  peculiar  of  any  ever  yet  published  in  reference  to  the  blood  corpuscle;  when  first 
they  were  announced  in  the  pages  of  the  Philosophical  Transactions,  the  scientific 
world  were  taken  by  surprise  and  wonderment.  Microscopes,  which  had  long  been 
suffered  to  remain  undisturbed  on  their  shelves,  were  immediately  had  recourse  to, 
and  many  scientific  men,  who  previously  had  never  employed  the  instrument  in  their 
investigations,  were  induced  to  procure  it,  in  order  that  they  might  themselves  bear 
ocular  witness  of  the  astonishing  facts  related  by  Dr.  Barry  in  reference  to  blood 
corpuscles.  A  short  abstract  of  Dr.  Barry's  views  will  be  read  by  some  with  interest. 
Dr.  Barry  considers  that  the  molecules,  the  red  corpuscles,  and  the  white  globules, 
are  different  states  of  the  development  of  the  same  structure,  the  true  blood  globule. 
(This  is  also  the  opinion  of  Addison  and  Donne.)  The  first  he  denominates  a 
"disc,"  and  the  last  a  "parent  cell."  These  different  stages  in  the  development  of  the 
blood  globule,  Dr.  Barry  compares  with  similar  conditions  of  the  germinal  vesicle  of 
the  ovum.  "The  disc,"  he  says,  "is  the  most  primitive  object  we  are  acquainted 
with;"  that  it  is  synonymous  with  the  "nucleus"  of  most  authors,  and  the  "basin- 
shaped  granules"  of  Vogel ;  that  it  "  contains  a  cavity,  or  depression,"  "  the  nucleo- 
lus," which  "  is  the  situation  of  the  future  orifice,"  which  he  says  the  blood  corpuscle 
in  certain  states  exhibits,  and  "by  means  of  which  there  is  a  communication  between 
the  exterior  of  the  corpuscle  and  the  cavity  in  its  nucleus ;"  lastly,  the  disc  is 
regenerated  by  fissiparous  divisions.  These  discs  are  also  denominated,  "  primitive 
discs,"  "foundations  of  future  cells."  The  "parent  cells"  he  conceives  to  be  made 
up  of  an  assemblage  of  these  discs.  Again,  Dr.  Barry  states,  "  The  nuclei  of  the 
blood  corpuscles  furnish  themselves  with  cilia,  revolve,  and  perform  locomotion;" 
"the  primitive  discs  exhibit  an  inherent  contractile  power."  And  of  the  corpuscles 
themselves,  he  remarks,  "  Molecular  motions  are  discernible  within  the  corpuscles  of 
the  blood," — "  changes  of  form  are  observed  under  peculiar  circumstances  in  the 
corpuscles  of  the  blood."  These  are,  however,  only  the  beginning  of  wonders  related. 
Dr.  Barry  elsewhere  goes  on  to  observe :  "  In  the  mature  blood  corpuscle  (red  blood 

1  See  British  and  Foreign  Medical  Review,  No.  xxvni.        2  Guy's  Hospital  Reports,  1840. 


96  OEGAN1ZED     FLUIDS. 

the  blood  disc  of  the  mammiferous  vertebrata,  viz:  the  outer  or 
capsular  portion  of  it — the  nucleus  which  alone  exists  in  the  blood 
corpuscles  of  birds,  fishes,  and  reptiles,  being  entirely  destitute  of 
colouring  matter. 

The  colour  of  the  blood,  it  has  long  been  believed,  is  intimately 

disc),  there  is  often  to  be  seen  a  flat  filament  or  band  already  formed  within  the 
corpuscle.  In  Mammalia,  including  man,  this  filament  is  frequently  annular;  some- 
times the  ring  is  divided  at  a  certain  part,  and  sometimes  one  extremity  over-laps  the 
other.  In  birds  and  amphibia  the  filament  is  of  such  length  as  to  be  coiled.  This 
filament  is  formed  of  the  discs  contained  within  the  blood  corpuscle. . .  "The  fila- 
ment thus  formed  within  the  blood  corpuscle  has  a  structure  which  is  very  remarka- 
ble. It  is  not  only  flat,  but  deeply  grooved  on  both  surfaces,"  in  an  oblique  manner. 
"It  is  deserving  of  notice,"  continues  Dr.  Barry,  "that  in  the  first  place,  portions  of 
coagulum  of  blood  sometimes  consist  of  filaments  having  a  structure  identical  with 
that  of  the  filaments  formed  within  the  blood  corpuscle;  secondly,  that  in  the  coagu- 
lum I  have  noticed  the  ring  formed  in  the  blood  corpuscle  of  man,  and  the  coil  formed 
in  that  of  birds  and  reptiles,  unwinding  themselves  into  the  straight  and  often  parallel 
filaments  of  the  coagulum,  changes  which  may  be  seen  also  taking  place  in  blood 
placed  under  the  microscope  before  coagulation;  thirdly,  that  I  have  noticed  similar 
coils  strewn  through  the  field  of  view  when  examining  various  tissues,  the  coils  here 
also  appearing  to  be  altered  blood  corpuscles  and  unwinding;  lastly,  that  filaments 
having  the  same  structure  as  the  foregoing,  are  to  be  met  with  apparently  in  every 
tissue  of  the  body."  These  filaments  Dr.  Barry  conceives  finally  to  constitute  "fibre," 
whenever  this  elementary  structure  is  encountered. 

These  multiplied  and  extraordinary  observations  of  Dr.  Barry,  it  is  now  necessary 
to  observe,  remain  unconfirmed  in  all  the  most  essential  particulars  up  to  the  present 
time.  Shortly  after  their  promulgation,  Dr.  Griffiths,1  and  Mr.  Wharton  Jones,2 
objected  to  the  statement  of  Dr.  Barry,  that  there  exists  in  the  blood  corpuscle  a  pri- 
mordial fibre,  observing  that  the  appearances  relied  upon  were  due  to  decomposition. 
In  connexion  with  the  subject  of  fibre  in  the  blood  globules,  the  analogy  referred  to 
by  Dr.  Willshire,  3  between  a  dark  line  observed  in  the  starch  vesicle,  and  Dr.  Barry's 
alleged  fibre,  may  be  noticed,  as  well  as  the  affirmations  of  Dr.  Carpenter,  4  that  Dr. 
Barry  had  shown  him,  among  corpuscles  of  the  blood  of  the  newt,  preserved  in  its 
own  serum,  many  of  a  flask-like  figure,  and  which  might  be  compared  to  a  pair  of 
bellows,  and  the  projecting  portion  of  which  appeared  to  Dr.  Carpenter  to  be  a  fila- 
ment having  a  much  higher  refracting  power  than  the  general  substance  of  the  cor- 
puscle. Dr.  Barry  also  showed  Dr.  Carpenter,  in  blood  preserved  in  corrosive  sublimate, 
a  corpuscle  which  was  evidently  destitute  of  the  ordinary  nucleus,  and  which  contained 
what  appeared  to  be  a  filament,  presenting  transverse  oblique  markings  which 
resembled  those  of  the  fibrillfe  of  a  muscle.  The  observations  of  Dr.  Barry,  and  the 
confirmatory  statements  of  Dr.  Carpenter,  will  at  least  be  possessed  of  historical 
interest,  if  any  real  and  intrinsic  importance  be  denied  to  them.  The  views  of  Dr. 
Barry  are  given  at  length  in  the  Philosophical  Transactions  for  1840 — 1843. 

l  Annals  of  Natural  History  February,  1843.    2  Transactions  of  the  Royal  Society,  December,  1842. 
3  Annals  of  Natural  History,  1843.  4  Annals  of  Natural  History,  1842. 


THE     BLOOD.  97 

connected  with  the  presence  of  iron  in  the  blood  corpuscles :  from  the 
fact,  however,  that  iron  exists  in  the  chyle,*  and  in  the  colourless 
blood  of  certain  animals,f  it  is  clear  that  the  mere  presence  of  iron  is  not 
in  itself  sufficient  to  account  for  the  colour  of  the  blood ;  this  depends 
most  probably  upon  the  state  of  combination  of  the  iron  in  the  blood. 
Liebig  states,  as  will  be  shown  immediately,  that  the  iron  in  the 
blood  exists  in  the  varying  conditions  of  peroxide,  protoxide,  and 
corbonate  of  the  protoxide  of  iron. 

USES    OF    THE    RED    CORPUSCLES. 

In  connexion  with  Respiration. — Observation  has  taught  us  the 
fact  that  the  colour  of  the  blood  changes  considerably,  according  as  it  is 
exposed  to  the  influence  of  oxygen  and  carbonic  acid  gases ;  it  becom- 
ing bright  red  under  the  influence  of  the  former,  and  dark  red,  almost 
black,  under  that  of  the  latter  gas. 

Now,  the  microscope  has  revealed  to  us  the  additional  fact  that  the 
colouring  matter  of  the  blood  resides  within  the  red  corpuscles ;  and 
hence  we  are  led  to  infer  that  the  changes  of  colour  alluded  to  are 
accompanied  by  alterations  in  the  condition  of  the  colouring  matter 
contained  in  those  corpuscles. 

Further,  the  alterations  of  colour  which  have  been  mentioned  take 
place  not  only  in  blood  withdrawn  from  the  system,  but  also  in  that 
which  still  circulates  in  the  living  body,  the  vital  fluid  being  exposed 
in  the  lungs  to  the  influence  of  the  oxygen  contained  in  the  atmosphere, 
and  to  carbonic  acid  in  the  capillary  system  of  vessels. 

But  it  is  not  merely  a  change  of  colour  which  the  blood  undergoes, 
or  rather  the  coloured  blood  corpuscles  undergo,  on  exposure  to  either 
of  the  gases  particularized,  but  they  also  experience  at  the  same  time, 
as  might  easily  be  inferred,  a  positive  change  of  condition,  a  portion 
of  one  or  other  of  the  gases  to  which  the  blood  corpuscles  are  exposed 
being  imbibed  by  them. 

That  it  is  really  the  red  corpuscles  which  absorb  the  oxygen,  or  the 
carbonic  acid,  as  the  case  may  be,  admits  of  demonstration,  and  is 
proved  by  the  fact  that  these  gases  lose  but  little  volume  when  placed 
in  contact  with  the  liquor  sanguinis,  or  serum  of  the  blood. 

*  See  article  "  Lymphatic  System,"  by  Mr.  Lane.  Encyclopardia  of  Anatomy  and 
Physiology,  April,  1841. 

f  "The  Blood  Corpuscle  considered  in  its  different  Phases  of  Development  in  the 
Animal  Series,"  by  J.  W.  Jones,  F.  R.  S.  Transactions  of  the  Royal  Society,  part  ii. 
for  1846. 

7 


98  ORGANIZED     FLUIDS. 

It  is  clear,  then,  that  the  coloured  corpuscles  are  the  seat  in  which 
these  changes  occur.  Again,  from  the  fact  that  the  blood  becomes 
bright  red  or  arterial  on  exposure  to  oxygen,  as  in  the  lungs,  and  dark 
red  or  venous  on  being  submitted  to  the  action  of  carbonic  acid,  as  in 
the  capillaries,  it  has  been  inferred  that  they  are,  first,  carriers  of 
oxygen  from  the  lungs  to  all  parts  of  the  system,  and,  second,  vehicles 
for  the  conveyance  of  carbon  back  again  to  the  lungs. 

This  inference  is  correct  as  far  as  it  goes,  but  it  fails  to  explain 
why  the  imbibition  of  oxygen  or  carbonic  acid  gases  should  be 
accompanied  by  changes  in  the  colour  of  the  blood ;  and  it  also  fails 
to  show  why  those  gases  themselves  should  be  imbibed. 

From  the  constant  presence  of  iron  in  the  coloured  blood  corpuscles, 
it  has  been  inferred  that  this  is  the  base  with  which  the  oxygen  and  the 
carbonic  acid  gases  combine,  but  the  exact  nature  of  the  combi- 
nations thus  formed  it  was  reserved  for  the  illustrious  Liebig  to  make 
known. 

Liebig  declares  that,  in  arterial  blood,  the  iron  is  in  the  state  of  a 
peroxide,  and  in  venous  blood  in  the  condition  of  a  carbonate  of  the 
protoxide. 

To  this  conclusion  Liebig  has  arrived  by  observing  the  manner  in 
which  the  above-mentioned  compounds  of  iron  comport  themselves 
when  not  in  connexion  with  the  blood,  but  when  exposed  to  the  same 
influences  as  the  blood  itself  is  subjected  to. 

Thus,  he  says,  "  The  compounds  of  the  protoxide  of  iron  possess  the 
property  of  depriving  other  oxydised  compounds  of  oxygen,  while  the 
compounds  of  peroxide  of  iron  under  other  circumstances  give  up 
oxygen  with  the  greatest  facility." 

Again,  "  Hydrated  peroxide  of  iron,  in  contact  with  organic  matters 
destitute  of  sulphur,  is  converted  into  carbonate  of  the  protoxide." 

Lastly,  "Carbonate  of  protoxide  of  iron  in  contact  with  water  and 
oxygen  is  decomposed,  all  the  carbonic  acid  is  given  off,  and  by 
absorption  of  oxygen  it  passes  into  the  hydrated  peroxide,  and  which 
may  again  be  converted  into  a  compound  of  the  protoxide." 

Now,  the  above-described  changes,  which  the  compounds  of  iron 
when  exposed  to  the  same  influences  as  the  blood  corpuscles  are 
themselves  submitted  to,  precisely  correspond  with  those  alterations 
which  it  is  known  and  ascertained  that  the  blood  corpuscles  do  them- 
selves experience,  and  therefore  there  is  every  probability  in  favour  of  the 
strict  accuracy  of  Liebig's  explanation  of  the  chemical  changes  which 
the  blood  corpuscles  pass  through  during  respiration  and  circulation. 


THE     BLOOD.  99 

Thus,  it  has  been  long  known,  that  in  the  lungs  the  coloured  blood 
corpuscles  give  off  carbonic  acid,  and  imbibe  oxygen:  and  it  has  also 
been  ascertained  that  during  their  circulation  they  lose  a  portion  of 
their  oxygen,  and  acquire  carbon. 

Venous  blood,  then,  exposed  to  the  air,  gives  out  carbonic  acid,  and 
absorbs  oxygen;  but  arterial  blood,  submitted  to  the  same  influence, 
gives  out  oxygen,  and  acquires  carbonic  acid;  the  seat  of  these  changes 
being  the  red  corpuscles. 

It  will  be  seen,  on  reflection,  that,  according  to  the  views  just  pro- 
pounded, the  surplus  amount  of  oxygen  which  exists  in  the  peroxide, 
becomes  disengaged  in  the  reduction  of  that  oxide  to  the  state  of 
protoxide:  during  circulation  in  the  capillaries,  this  surplus  is  chiefly 
expended  in  the  elaboration  of  the  different  secretions  which  are 
continually  being  formed  in  the  various  organs  of  the  body. 

Such  is  the  corpuscular  theory  of  respiration.  Hereafter  we  shall 
have  to  speak  of  a  corpuscular  theory  of  nutrition,  growth,  and 
secretion. 

In  connexion  with  Secretion. — It  is  very  probable  that  the  use  of 
the  red  corpuscles  is  not  limited  to  the  mere  office  of  carrying  oxygen 
from  the  lungs  to  be  distributed  to  all  parts  of  the  system,  and  of  carbon 
back  again  to  the  lungs  to  be  eliminated,  but  that  they  have  an  ulterior 
and  additional  function  to  discharge.  Thus,  some  observers  suppose 
that  they  exert  some  influence  over  the  constitution  of  the  blood  itself, 
elaborating,  from  the  materials  continually  thrown  into  it  by  the  tho^ 
racic  duct,  a  further  quantity  of  fibrin.  There  is  more  reason  to  believe, 
however,  that  it  is  the  white  corpuscles  which  are  principally  concerned 
in  this  process  of  elaboration,  seeing  that  their  structure  agrees  with 
that  which  is  generally  possessed  by  true  secreting  cells.  I  therefore 
myself  would  be  inclined  to  attribute  to  the  red  corpuscles  but  little 
influence  over  the  constitution  of  the  blood. 

It  may  be  stated  that  both  Wagner*  and  Henle  are  of  opinion  that 
the  red  corpuscles  are  connected  with  secretion,  and  the  latter,  in  his 
"General  Anatomy,"  calls  them  " swimming  glandular  cells." 

Effects  of  Reagents. 

The  blood  globules  are  much  modified  by  tne  application  of  numer- 
ous reagents,  and  which,  therefore,  may  be  employed  with  advantage 
in  their  investigation. 

*  Physiology,  by  Willis,  part  ii.  p.  448. 


100  ORGANIZED     FLUIDS. 

Serum. — It  has  already  been  observed  that,  in  the  serum  of  the 
blood,  their  natural  element,  the  globules  preserve  unaltered,  for  a 
time,  their  normal  form. 

Water. — The  application  of  water  causes  the  globules  almost 
immediately  to  lose  their  flattened  and  discoidal  character,  the  depres- 
sions on  their  surface  are  effaced,  and  they  become  spherical.  This 
change  in  the  form  of  the  corpuscles  is  necessarily  accompanied  by  a 
diminution  of  their  size.     (See  Plate  I.  jig.  3.) 

Spirits  of  Wine,  JEther,  Creosote. — The  same  results  follow  the 
use  of  a  variety  of  liquids,  as  spirits  of  wine,  aether  and  creosote. 
These  agents,  however,  in  addition,  render  the  globules  exceedingly 
diaphanous,  so  much  so  indeed  as  that  they  are  often  with  difficulty 
to  be  discovered.  In  the  globules  rendered  thus  transparent,  no  traces 
of  granular  contents  can  be  detected. 

Acetic  acid. — This  preparation  first  deprives  the  globules  of  their 
colouring  matter,  thus  rendering  them  exceedingly  transparent,  and 
subsequently  dissolves  the  human  blood  corpuscle,  without  residue, 
but  not  that  of  a  frog,  &c,  the  nucleus  of  which  remains  entire. 
(See  Plate  II.  fig.  5.) 

Ammonia. — This  alkali  acts  in  a  similar  manner. 

Nitric  Acid,  Muriate  of  Soda. — These  reagents  contract  the 
globules,  and  render  their  outline  more  distinct. 

Iodine. — This  likewise  renders  the  outlines  more  distinct,  without 
at  the  same  time  deforming  and  otherwise  altering  the  globules. 

Corrosive  Sublimate. — In  a  strong  solution  of  this  liquid,  the  outlines 
of  the  globules  are  more  defined,  and  the  globules  may  be  preserved 
for  examination  for  a  considerable  length  of  time. 

We  shall  next  pass  to  the  consideration  of  the  white  globules,  and 
show  in  what  particulars  of  form  and  structure  they  differ  from  the  red. 

WHITE    GLOBULES. 

The  white  globules  of  the  blood  are  by  far  less  numerous  than  the 
red;  they  nevertheless  are  more  abundant  than  a  superficial  observer 
would  suppose :  this  arises  from  the  fact  that  many  of  them  are  con- 
cealed from  view  on  the  field  of  the  microscope  by  the  red  globules, 
which  so  greatly  outnumber  them.  The  white  corpuscles  differ  from 
the  red  in  several  particulars :  in  size,  in  colour,  in  form,  in  structure, 
in  their  properties,  and  doubtless  also  in  their  uses.* 

*  Spallanzani  was  the  first  to  notice  the  existence  of  two  forms  of  globules  in  the 
blood  of  salamanders;  Miiller  verified  their  presence  in  that  of  the  frog,  and  M.  Mandl 
detected  them  in  man  and  mammalia. 


THE     BLOOD.  101 

Size. — In  man  and  the  mammalia  the  white  globules  are  generally- 
larger  than  the  red :  like  those,  also,  their  dimensions  vary  very  con- 
siderably in  the  blood  of  the  same  individual  abstracted  at  any  given 
time,  and  even  to  an  extent  still  greater.  Their  average  size,  when 
contained  in  the  serum  of  the  blood,  may,  however,  be  estimated  at 
about  the  ^jVo  °f  an  inch*  (see  Plate  I.  fig.  1) :  when  immersed  in 
water,  however,  they  swell  up,  and  increase  very  considerably  in  size, 
in  this  liquid  sometimes  measuring  the  TJ~  of  an  inch.  (See  Plate  I. 
fig.  6.)  In  the  blood  of  reptiles,  especially  in  that  of  the  frog,  a 
contrary  relation  between  the  size  of  the  red  and  white  globules  exists ; 
the  latter  in  these,  instead  of  being  larger  than  the  red  corpuscles, 
are  two  or  even  three  times  smaller.  This  fact  it  is  important  to  bear 
in  mind,  in  considering  the  question  of  the  transformation  of  the  white 
globules  into  red. 

Form. — Instead  of  being  of  a  flattened  and  disc-like  form,  as  are 
the  red  globules,  the  shape  of  the  white  corpuscle,  when  free,  is  in  all 
classes  of  the  animal  kingdom  globular.  This  particular  likewise 
throws  much  light  upon  the  disputed  point  as  to  whether  the  white 
globules  become  ultimately  converted  into  red  corpuscles,  and  which 
we  shall  have  to  treat  of  more  fully  hereafter. 

Like  the  red  corpuscles,  however,  although  to  a  less  remarkable 
extent,  the  white  globules,  when  subject  to  pressure,  undergo  a  change 
of  form :  this  change  is  frequently  well  seen  when  viewing  the  circu- 
lation of  the  blood  in  the  capillaries,  the  white  corpuscles  often  becom- 
ing compressed  between  the  walls  of  the  vessels  and  the  current  of 
red  blood  discs,  and  by  which  compression  they  are  made  to  assume 
elongated  and  oval  forms ;  like  the  red  corpuscles,  also,  they  immedi- 
ately regain  their  normal  form,  the  pressure  being  removed. 

Structure. — In  almost  every  relation  which  can  be  named,  the 
white  globules  would  appear  to  be  the  antagonists  of  the  red;  for, 
instead  of  being  of  a  homogeneous  texture,  they  are  of  a  granular 
structure  throughout,  each  full-sized  white  globule  being  constituted 
of  not  less  than  from  twenty  to  thirty  distinct  granules,  the  presence 
of  which  imparts  to  it  a  somewhat  broken  outline:  these  granules 
are  often  seen,  especially  after  the  addition  of  water,  and  some  other 
reagents,  to  be  in  a  state  of  the  greatest  activity  in  the  interior  of  the 
corpuscles.  It  is  only  in  the  blood  globule  of  mammalia,  however, 
that  we  find  this  antagonism  to  prevail.     The  blood  corpuscle  of  the 

*  Mr.  Gulliver  gives  the  2T0  „-  °f  an  inen  as  the  average  measurement  of  the  human 
colourless  blood  corpuscle. 


102  ORGANIZED     FLUIDS. 

frog,  and  doubtless  of  other  reptiles,  as  well  as  birds  and  fishes,  is 
assuredly  a  compound  structure,  the  investing  or  transparent  part  of 
each  being  in  no  way,  as  regards  structure,  distinguishable  from  the 
substance  of  the  human  blood  disc,  and  the  nucleus  also  being  iden- 
tical in  composition,  though  not  in  origin,  with  the  white  globules  of 
the  blood,  not  merely  of  mammalia,  but  likewise  of  reptiles,  birds, 
and  fishes.     (See  Plate  II.  fig.  5.)     The  form  of  the  nucleus,  in  the 
frog,  &c,  corresponds  with  that  of  the  globule;  that  is,  it  is  elliptical 
(see  Plate  II.  fig.  2) :  water,  however,  affects  the  nucleus,  as   first 
observed  by  Mandl,  in  the  same  way  as  it  acts  upon  the  corpuscle 
itself,  rendering  both  perfectly  spherical.    (See  Plate  W.figs.  3  and  4.) 
If  to  globules  in  this  condition  acetic  acid  be  added,  the  capsule  will 
be  dissolved,  leaving  intact  the  nucleus,  between  which  and  a  white 
globule  I  have  not  been  able  to  detect,  although  using  an  instrument 
of  the  very  best  description,  the  slghtest  structural  difference:   a  dif- 
ference does  certainly  exist,  but  it  is  one  of  size,  and  not  of  structure, 
the  nucleus  being  three  or  four  times  smaller  than  a  white  globule  of 
ordinary  dimensions.     (See  Plate  11.  fig.   5,  and  Plate   II.  fig.    1.) 
This  identity  of  organization  between  the  white  globule   and  the 
nucleus  of  the  blood  disc  of  the  frog,  furnishes  the  strongest  evidence 
with  which  I  am  acquainted  of  the  convertibility  of  the  white  glob- 
ules into  red,  evidence  which,  nevertheless,  I  regard  as  wholly  inade- 
quate to  demonstrate  the  reality  of  the  conversion. 

Nucleus. — The  white  corpuscles,  under  some  circumstances,  would 
appear  to  be  nucleated ;  thus  nuclei  are  evident  in  corpuscles  which 
have  been  immersed  in  water,  or  even  in  serum,  for  any  length  of 
time,  although  they  are  not  usually  seen  in  those  of  that  fluid  imme- 
diately after  its  abstraction  from  the  system.  I  am  inclined  to  regard 
their  formation  as  resulting  partly  from  the  operation  of  endosmosis, 
whereby  a  portion  of  the  contents  of  each  corpuscle  becomes  con- 
densed in  the  centre. 

The  nucleus  occupies  sometimes  the  entire  of  the  interior  of  the 
corpuscle,  a  narrow  and  colourless  border  destitute  of  granules,  alone 
indicating  the  extent  of  the  corpuscle;  generally,  however,  it  is  about 
the  one-third  of  its  size,  and  is  more  frequently  eccentric  than  centric. 
It  is  usually  darker  than  the  rest  of  the  corpuscle,  and  would  appear 
to  contain  a  greater  number  of  molecules.  (See  Plate  I.  fig.  6.) 
Sometimes  it  presents  to  the  eye  of  the  observer  the  appearance  of 
an  aperture;  this  appearance,  although  very  striking,  is  most  probably 
fallacious. 


THE     BLOOD.  103 

Mr.  Addison  regards  the  nucleus  presented  by  the  white  corpuscles 
as  primary,  an  opinion  in  which  I  concur. 

Properties. — The  white  corpuscles  of  the  blood  differ  not  less  in 
their  properties  from  the  red  than  they  do  in  form  and  structure: 
thus,  acetic  acid,  which  dissolves  the  latter,  contracts  somewhat  the 
former,  and  renders  the  contained  granules  more  distinct;  in  water, 
the  red  globules  become  globular  and  smaller  in  size,  while  the  white 
increase  considerably  in  dimensions  in  the  same  liquid  (see  Plate  I. 
fig.  6),  and  finally  burst  in  it,  their  molecular  contents  escaping.  In 
liquor  potasses,  both  the  red  and  white  corpuscles  are  destroyed  and 
dissolved ;  previous  to  which,  however,  in  the  white  globules,  some 
interesting  changes  are  seen  to  take  place ;  immediately  on  the  appli- 
cation of  the  alkali,  the  molecules  contained  in  their  interior  are 
observed  to  be  in  active  motion,  and  in  a  short  time  the  corpuscles 
burst  open,  or  explode,  discharging  numerous  granules,  amounting 
sometimes  to  thirty  or  forty;  and  which,  together  with  the  transpa- 
rent matter  of  the  corpuscles,  finally  becomes  dissolved. — "Frequently, 
when  the  liquor  potassee  is  acting  with  diminished  energy,  the  cor-» 
puscles  give  a  sudden  jerk,  and  in  a  moment  enlarge  to  double  or 
three  times  their  former  size,  without  losing  their  circular  outline: 
the  molecules  and  granules  within  them  are  more  widely  separated 
from  each  other,  but  not  dispersed;  and  they  are  seen  held  together, 
or  attached  to  the  tunic  of  the  corpuscle,  by  delicate  connecting  fila- 
ments. This  singular  and  instructive  change  does  not,  of  course, 
last  long;  the  alkali,  continuing  its  action,  ruptures  the  tunic  of  the 
corpuscle,  dispersing  and  dissolving  its  contents." — Addison. 

When  examined  in  the  living  capillary  vessels,  they  are  seen  to 
manifest  different  properties  to  the  red,  and  also  to  have  a  very  different 
distribution  in  those  vessels.  Thus,  the  white  corpuscles  frequently 
adhere  to  the  inner  wall  of  the  capillaries,  which  the  red  rarely  do ; 
and  while  the  red  globules,  in  circulating,  occupy  the  centre  of  each 
vessel,  the  white  corpuscles  are  placed  between  this  and  the  walls  of 
the  vessel. 

A  difference  may  also  be  observed  in  the  relative  speed  with  which 
the  two  kinds  of  corpuscles  circulate,  the  red  flowing  onwards  with 
greater  rapidity  than  the  white.  The  forces  which  determine  the 
circulation  in  the  vessels  would  appear  to  act  only  on  the  red  cor- 
puscles, the  motion  of  the  white  globules  being  entirely  of  a  secondary 
and  indirect  character,  it  being  communicated  to  them  by  the  edge 
of  the  current  in  the  axis  of  which  the  red  corpuscles  move,  in  the 


104  OEGANIZED     FLUIDS. 

same  way  as  the  stones  at  the  bottom  of  a  stream  are  rolled  over  and 
borne  onwards  by  the  superincumbent  water. 

The  cause  of  the  slower  motion  of  the  white  corpuscles  in  the 
capillaries  may  be  thus  explained.  A  greatly  retarded  motion  of  the 
fluid  circulating  in  any  vessel  or  channel  is  always  observed  towards 
the  periphral  border  of  the  current.  This  retardation  would  appear 
to  arise  from  the  resistance  which  the  circulating  fluid  encounters 
by  coming  in  contact  with  the  walls  of  the  vessel  or  sides  of  the 
channel  through  which  it  flows. 

In  what  way,  however,  is  the  difference  in  the  position  in  the  ves- 
sels occupied  by  the  red  and  white  corpuscles  to  be  explained?  whv 
do  the  former  always  circulate  in  the  axis  of  the  vessel,  while  the 
latter  are  constantly  placed  outside  this  ?  and  what  is  the  inference  to 
be  deduced  from  this  difference  in  their  situation  ? 

The  red  corpuscles,  as  we  know,  are  flattened  discs,  constituted  of 
an  elastic  and  yielding  material;  and  the  white,  on  the  contrary,  are 
globular  bodies  of  a  more  dense  composition  and  of  but  little  elasticity. 
*Now,  it  is  very  probable  that  the  peculiar  form  and  properties  pos- 
sessed by  the  coloured  corpuscles  of  the  blood  may  result  in  such  an 
adaptation  and  arrangement  of  them,  the  one  with  the  other,  that  a 
physical  impossibility  is  presented  to  their  indiscriminate  admixture 
and  circulation  in  the  same  vessel  with  the  white  corpuscles. 

But  there  are  other  facts  which  will  serve  to  explain  the  difference 
of  position:  Thus,  the  red  corpuscles  have  an  attraction  for  each 
other,  as  is  manifested  on  the  field  of  the  microscope  by  the  formation 
of  the  strings  of  corpuscles  already  referred  to,  where  also  it  is  seen 
that  they  have  no  such  affinity  for  the  white  corpuscles,  which 
usually  lie  detached  and  isolated  from  the  red.  On  the  other  hand, 
however,  the  white,  as  before  stated,  have  an  attraction  for  the  walls 
of  the  vessels  through  which  they  pass,  and  which  is  declared  by 
their  frequent  adhesion  thereto. 

The  question  may  be  asked,  have  these  attractions  any  thing  to  do 
with  electric  conditions?  All  the  inquiries  which  have  been  under- 
taken, with  the  view  of  proving  that  the  blood  is  possessed  of  electric 
properties,  have  hitherto  signally  failed  to  demonstrate  the  existence 
of  any. 

Lastly,  what  inference  is  to  be  deduced  from  the  different  positions 
occupied  by  the  two  kinds  of  blood  corpuscles,  and  from  the  different 
rates  of  their  circulation  in  the  capillaries  ? 

The  rapid  passage  of  the  red  corpuscles  through  the  capillaries, 


THE     BLOOD.  105 

together  with  their  central  situation,  would  lead  the  observer  to  infer 
that  they  had  but  little  direct  relation  with  the  parts  outside  those 
capillaries;  that  the  office  discharged  by  them  was  one  of  distribu- 
tion ;  whereas  the  slow  progress  of  the  white  corpuscles  through  the 
capillary  vessels,  as  well  as  their  peripheral  position,  would  lead  to 
the  conclusion  that  a  close  relation  existed  between  them  and  the 
parts  adjacent  and  external  to  the  vessels.  Now,  these  deductions 
are  precisely  those  which  other  facts  and  observations  tend  to  con- 
firm and  establish,  as  we  have  already  seen  in  reference  to  the  red 
corpuscles,  and  as  we  shall  immediately  proceed  to  show  in  relation 
to  the  white  globules. 

While  viewing  the  capillary  circulation,  it  is  easy  to  convince 
oneself  that  no  contraction  of  the  parietes  of  the  capillaries  occurs, 
and  that,  therefore,  the  motion  of  the  blood  is  independent  of  any 
action  of  those  vessels  themselves,  on  their  contents. 

USES    OF    THE    WHITE    CORPUSCLES. 

The  uses  of  the  white  corpuscles  have  not  as  yet  oeen  fully  deter- 
mined; enough,  however,  of  their  nature  has  been  ascertained  to 
show  that  they  are  closely  connected  with  the  functions  of  Nutrition 
and  Secretion.  We  shall  here  invert  the  natural  order  in  which  the 
description  of  these  subjects  should  be  entered  upon,  and  speak  first 
of  secretion. 

Uses  in  connexion  with  Secretion. — It  would  appear  that,  for  the 
most  part,  secretions  are  formed  in  cells :  the  correctness  of  this 
statement  is,  in  some  degree,  proved  by  the  fact  that  the  lower  classes 
of  the  vegetable  kingdom  are  entirely  constituted  of  cellular  tissue. 

It  is  also  further  supported  by  the  fact,  that  the  essential  structure 
of  all  glands  in  the  animal  frame  is  that  of  cells. 

It  would  appear,  also,  that  the  cells,  entering  into  the  composition 
of  a  single  organ,  have  the  power  of  producing  more  than  one  kind 
of  secretion.  This  is  witnessed  in  the  petals  of  many  flowers,  the 
cells  of  which  frequently  elaborate  fluids  of  several  distinct  colours. 

There  is  much  reason  to  believe,  that  the  granules,  which  are  so 
constantly  associated  with  the  cells,  are  the  active  agents  engaged  in 
the  production  of  the  secretion,  the  exact  constitution  of  these  granules 
determining  the  character  of  the  secreted  product. 

Now,  in  the  white  corpuscles  of  the  blood  we  have  precisely  the 
same  granular  constitution  which  is  seen  to  belong  to  cells  which  are 
indisputably  engaged  in  the  process  of  secretion. 


106  ORGANIZED     FLUIDS. 

From  the  observation  of  these  and  other  facts,  Mr.  Addison  has 
been  led  to  entertain  the  opinion,  that  the  white  corpuscles  of  the 
blood  "are  very  highly  organized  cells,  from  which  the  special  tissues 
and  the  secretions  are  elaborated."*  In  continuation  of  this  subject, 
Mr.  Addison  goes  on  to  remark :  "And  it  appears  that  the  renovation 
of  these  tissues  and  secretions  from  the  blood  does  not  take  place  by 
the  cells  discharging  their  contents  into  the  general  mass  of  the 
circulating  current,  to  be  separated  therefrom  by  some  peculiar 
transcendental  and  purely  hypothetical  selective  process  of  exudation, 
through  a  structureless  and  transparent  tissue,  but  by  being  them- 
selves attached  to,  incorporated  with,  and  performing  their  special 
function  in  the  structure." 

Thus,  Mr.  Addison  conceives  that  the  fibrillating  liquor  sanguinis 
is  formed  and  elaborated  in  the  white  corpuscles  of  the  blood,  and 
that  it  never  exists  in  that  fluid  in  a  free  state,  and  that  its  presence 
in  the  crassamentum,  and  especially  in  that  part  of  it  which  consti- 
tutes the  buffy  coat,  arises  from  the  rupture  and  destruction  of  the 
white  corpuscles,  and  the  escape  of  their  contents.  This  opinion  he 
supports  by  a  series  of  ingenious  experiments,  one  of  which  may  here 
be  referred  to.  The  tenacious  property  belonging  to  mucus  is  well 
known,  in  which  respect,  as  well  as  in  the  smaller  number  of  globules, 
similar  to  the  white  corpuscles  of  the  blood  contained  in  it,  it  differs 
mainly  from  pus.  Now,  by  the  addition  of  a  drop  of  liquor  potasses 
to  a  little  pus,  which  was  previously  white  and  opaque,  and  in  which 
the  presence  of  a  considerable  number  of  white  corpuscles  was 
ascertained  by  means  of  the  microscope,  its  appearance  underwent  a 
complete  change,  the  pus  became  transparent  and  tenacious,  presenting 
precisely  the  characters  of  mucus.  The  fluid  being  again  examined 
microscopically,  it  was  found  that  most  of  the  globules  were  ruptured 
and  dissolved,  and  that  the  liquid  portion  of  it  fibrillated  in  the  same 
way  as  that  of  mucus,  and  that  of  the  liquor  sanguinis ;  from  this 
and  other  analogous  experiments  Mr.  Addison  formed  the  conclusion, 
that  the  fibrillating  liquor  sanguinis  was  derived  from  the  white 
corpuscles,  and  that  it  does  not  exist  in  the  blood  in  a  free  condition. 

According  to  Mr.  Addison,  the  secretions,  "milk,  mucus,  and  bile, 
are  the  visible  fluid  results  of  the  final  dissolution  of  the  cells." 
Hence,  therefore,  a  secretion  is  the  result  of  the  last  stage  of  the 
process  of  nutrition.     And,  again,  "If,  therefore,  the  colourless  blood 

*  "Experimental  Researches,"  Transactions  of  Prox.  Med.  and  Surg.  Association, 
vol.  xii.  p.  260 


THE     BLOOD.  107 

corpuscles  be  termed  "parent  cells,"  they  must  be  considered  as 
pregnant  with  the  embryo  materials  of  the  tissues  and  secretions,  and 
not  with  "young  blood  cells." 

It  is  scarcely  necessary  to  observe  that  these  highly  ingenious 
views  of  Mr.  Addison  are  by  no  means  established.  That  the  cells 
of  glands  and  their  contained  granules  are  intimately  connected  with 
secretion,  there  are  many  facts  to  prove ;  but  that  the  white  corpus- 
cles of  the  blood  are,  in  the  animal  economy,  the  special  organs  of 
secretion,  and  also  that  the  secretions  said  to  be  elaborated  by  them, 
escape  from  them,  not  by  transudation  through  their  membranes,  but 
are  set  free  by  the  entire  and  final  dissolution  of  the  corpuscles,  are 
views  which  cannot  be  safely  adopted  until  much  additional  evidence 
is  adduced  in  support  of  them. 

The  opinion  entertained  by  Dr.  Barry,  that  the  colourless  corpuscles 
are  "parent  cells,"  seems  to  me  to  be  purely  hypothetical. 

Let  us  now  bestow  a  few  reflections  upon  Nutrition : 

Uses  in  connexion  with  Nutrition. — That  the  white  corpuscles  are 
concerned  in  the  process  of  nutrition,  there  is  more  evidence  to  show 
than  there  is  in  favour  of  their  connexion  with  that  of  secretion.  The 
question  to  be  solved,  however,  is,  in  what  way  do  these  corpuscles 
administer  to  nutrition  ?  do  they  contribute  to  nutrition  and  growth, 
by  their  direct  apposition  to  and  incorporation  with  the  different 
tissues  of  organs?  This  is  the  opinion  of  Mr.  Addison,  who  says  of 
them,  that  they  are  the  "foundations  of  the  tissues  and  the  special 
secreting  cells,  the  link  between  the  blood  and  the  more  solid  struc- 
tures, the  unity  from  which  the  pluralities  arise." 

Dr.  Martin  Barry  also  adopts  the  notion  that  tissues  are  formed  by 
the  direct  apposition  of  the  blood  corpuscles.  Dr.  Barry  makes  no 
exact  distinction  between  the  red  and  the  colourless  globules;  but 
from  the  fact  of  his  calling  the  latter  "parent  cells"  filled  with  "young 
blood  discs,"  it  would  appear  that  he  considered  that  the  red  corpuscles 
gave  origin  to  the  different  structures  of  the  body  by  their  direct  union 
and  incorporation  with  each  other.  This  view  is  far  less  tenable  than 
that  of  Mr.  Addison,  and  neither  is  supported  by  a  sufficient  number 
of  facts  to  render  its  accuracy  any  thing  but  exceedingly  problematical. 

That  the  white  corpuscles  of  the  blood  are  engaged  in  the  process 
of  nutrition  is  proved  by  the  fact,  that  they  are  found  in  increased 
quantities  in  vessels  which  are  actively  administering  to  that  function. 
This  accumulation  is  witnessed  also  in  the  capillary  vessels  of  any 
parts  which  are  subjected  to  irritation  of  any  sort,  and  in  which,  as  a 
consequence  of  that  irritation,  there  is  augmented  action. 


108  ORGANIZED     FLUIDS. 

The  gradual  collection  of  the  white  corpuscles  of  the  blood  in  the 
capillary  vascular  net-work,  may  be  seen  to  the  greatest  possible 
advantage  in  the  tongue  of  the  frog,  as  also  in  the  web  of  the  foot  of 
that  coveniently-formed  creature,  as  the  result  of  continued  exposure 
of  the  parts  to  the  action  of  air.* 

But  it  is  not  alone  the  aggregation  of  the  colourless  corpuscles  that 
may  be  seen  in  the  minute  vessels ;  their  escape  from  those  vessels 
may  likewise  be  determined  by  a  prolonged  examination  of  them.  If, 
after  the  continuance  of  this  congested  condition  of  the  vessels  for 
twenty-four  or  thirty-six  hours,  they  are  again  examined,  it  will  be 
obvious  that  certain  of  the  corpuscles  have  become  entangled  in  the 
fibres  which  form  the  walls  of  the  vessels,  and  that  certain  others 
have  altogether  passed  the  boundaries  of  the  vessels,  and  now  lie 
external  to  them. 

Again,  it  is  asserted,  that  the  epithelial  cells  are  derived  from  the 
white  corpuscles  of  the  blood.  If  this  be  correct,  it  would  appear 
that  the  escape  of  these  corpuscles  is  a  perfectly  normal  and  natural 
occurrence. 

Thus  far,  then,  the  endeavour  to  prove  the  transformation  of  the 
colourless  corpuscles  of  the  blood  into  tissue  cells,  would  appear  to  be 
successful;  but  it  is  here  the  chain  of  evidence  breaks;  and  beyond 
the  fact,  which  is  by  no  means  established,  of  their  constituting 
epithelial  cells,  we  have  no  further  proof  to  adduce  of  their  structural 
incorporation  with  the  living  tissues.  Of  this  occurrence  it  would,  of 
course,  be  difficult  to  procure  satisfactory  demonstration,  on  account 
of  the  opacity  of  the  parts  on  which  our  examination  would  have  to 
be  conducted.  It  may  be  remarked,  however,  that,  if  founded  in  fact, 
we  should  expect  to  find  a  greater  correspondence  in  the  size  and 
form,  &c,  of  the  elementary  tissues,  with  that  of  the  corpuscles  from 
which,  according  to  some  observers,  those  tissues  are  derived. f 

The  corpuscular  theory  of  nutrition,  then,  proposed  by  Mr.  Addison, 

*  Mr.  Addison  states  that,  in  order  to  insure  a  satisfactory  exhibition  of  this 
important  and  curious  phenomenon,  the  parts  should  be  irritated  in  some  manner,  as 
by  immersion  for  a  minute  or  two  in  warm  water  at  a  temperature  of  95°  Fahrenheit, 
or  by  permitting  a  few. crystals  of  common  salt  to  dissolve  upon  it.  These 
methods  I  have  tried,  and  have  found  that  they  have  usually  resulted  in  the  entire 
cessation  of  the  circulation  in  the  capillaries,  and  this  has  been  also  the  case  even 
when  a  weak  solution  of  salt  in  water  has  been  applied. 

f  The  cells  of  the  liver  and  spleen  resemble  closely  in  appearance  the  white  cor- 
puscles of  the  blood ;  between  them,  however,  well-marked  differences  exist,  so  that 
it  is  by  no  means  to  be  inferred  that  the  former  are  derived  directly  from  the  latter. 


THE     BLOOD.  109 

in  the  present  state  of  our  knowledge,  can  only  be  sustained  by  having 
recourse  to  a  certain  amount  of  theoretical  reasoning  or  to  particular 
assumptions. 

The  fact,  however,  still  remains  to  us,  that  the  white  corpuscles 
are  concerned  in  nutrition,  although  the  precise  manner  in  which  they 
are  so  is  still  open  to  investigation,  and  this  fact  is  strengthened  and 
confirmed  by  the  phenomena  of  disease.  Thus,  there  is  much 
evidence  to  show  that,  wherever  nutrition  is  impeded,  the  colourless 
corpuscles  accumulate  in  increased  quantities  in  the  vessels;  and  it  is 
by  this  accumulation,  also,  that  we  are  enabled  to  account  for  the 
critical  abscesses  and  discharges  which  characterize  some  affections, 
and  to  recognise  the  importance  which  ought  to  be  attached  to  their 
occurrence. 

That  the  colourless  corpuscles  are  really  present  in  increased 
numbers  in  the  blood,  in  disease,  is  attested  by  the  evidence  of  numer- 
ous observers:  thus,  Gulliver,*  Davy,f  and  Ancell,J  have  observed 
them  in  unusual  quantities  in  inflammatory  affections,  and  especially 
in  such  as  are  attended  with  suppuration.  Mr.  Siddall  and  Mr. 
Gulliver  have  repeatedly  observed  them  in  vast  numbers  in  the  horse, 
especially  when  the  animal  has  been  suffering  from  influenza.  Donne 
has  likewise  recognised  their  presence  in  increased  quantities  in 
disease;  and  Mr.  Addison  finds  them  to  abound  in  the  hard  and  red 
bases  of  boils  and  pimples,  and  in  the  skin  in  scarlatina  and  in  most 
cutaneous  affections. 

Several  processes  may  have  been  pointed  out  by  which  the  white 
globules  may  be  separated  from  the  red,  and  thus  be  brought  in  a 
manner  more  satisfactory  under  view.  1st.  Acetic  acid  dissolves  the 
red  corpuscles,  leaving  the  white  almost  unchanged.  2d.  A  drop  of 
water,  floated  gently  across  a  piecs  of  glass,  on  which  a  small  quantity 
of  blood  has  been  placed,  will  remove  the  red  corpuscles,  the  white 
remaining  adherent  to  the  surface  of  the  glass.  This  ingenious  method 
was,  I  believe,  first  indicated  by  Mandl.  3d.  The  third  process 
depends  for  its  success  upon  the  defibrination  of  the  blood  by  whipping, 
and  which  has  already  been  alluded  to.  If  blood  thus  defibrinated  be 
set  aside  for  a  time,  the  red  globules  will  subside  to  the  bottom  of  the 
containing  vessel,  forming  one  stratum,  and  the  serum  will  float  upon 
the  top,  constituting  a  second  layer ;  but  between  these  two  layers  a 

*  Appendix  to  Gerber's  General  Anatomy,  p.  20. 

f  Researches,  Phys.  and  Anal.,  vol.  ii.  p.  212. 

I  Lectures  in  the  Lancet,  1839-40,  vol.  ii.  p.  777. 


HO  ORGANIZED     FLUIDS. 

third  exists;  this  is  very  thin,  and  is  formed  by  the  white  globules, 
which  may  be  reached  after  the  removal  of  the  serum  by  means  of  a 
siphon.*  Donne  points  out  this  method  in  his  excellent  "Cours  de 
Microscopic"  4th.  A  fourth  means  of  procuring  the  white  globules 
is  described  by  Mr.  Addison.  If  a  portion  of  fluid  fibrin  be  removed 
from  beneath  the  pellicle  which  is  first  formed  over  the  clot,  it  will  be 
found  to  contain  numerous  white  globules. 

The  observer,  having  satisfied  himself  of  the  accuracy  of  the  various 
facts  brought  under  his  notice,  in  the  next  place  will  be  prepared  to 
enter  into  the  important  questions  as  to  the  origin  and  destination  of 
the  globules  of  the  blood.  We  will  consider  first  the  origin  of  the 
white  globules. 

ORIGIN    OF    THE    GLOBULES    OF    THE    BLOOD. 

The  origin  and  end  of  the  blood  globules !  Whence  do  they  come, 
and  whither  do  they  go  ?  These  are  questions  of  the  highest  import- 
ance ;  and  it  could  be  wished  that  the  replies  to  them  were  of  a  more 
satisfactory  and  definite  nature  than  those  which  we  are  about  to 
make  will,  it  is  feared,  be  considered. 

Origin  of  the  White  Globules. — Various  opinions  have  been  enter- 
tained in  reference  to  the  nature  and  origin  of  the  white  corpuscles 
of  the  blood,  the  principal  of  which  we  will  now  proceed  to  notice. 

One  of  the  earliest  notions  formed  respecting  the  white  corpuscles 
was  that  of  Hewson,  who  believed  that  they  were  to  be  considered  as 
the  nuclei  of  the  red  blood  corpuscles,  and  hence  he  denominated  them 
"central  particles:"  to  this  conclusion  Hewson  was  doubtless  led  by 
observing  the  great  and  remarkable  resemblance  which  exists  between 
the  nuclei  of  the  blood  globules  of  certain  animals  and  the  white 
corpuscles  themselves. 

Two  facts,  however,  are  known,  which  satisfactorily  prove  that  the 
denomination  of  central  particles  is  not  applicable  to  the  white  cor- 
puscles, and  that  they  do  not  form  the  nuclei  of  the  red  blood  discs; 
the  first  of  these  is,  that  no  nuclei  exist  in  the  true  blood  globules  of 
the  entire  class  of  mammalia  in  which  white  corpuscles  are  abundantly 
encountered,  and  the  second  is  the  great  difference  in  size  observed 

*  The  position  occupied  in  this  case  by  the  white  corpuscles  shows  that  they  are 
of  lighter  specific  gravity  than  the  red,  a  reference  to  which  fact  will  also  account  for 
their  presence,  in  such  quantities,  in  the  bufiy  coat  of  the  blood,  and  will  likewise 
explain  the  reason  why  they  first  come  into  focus  when  mixed  with  the  red  globules 
in  a  drop  of  water. 


THE     BLOOD.  Ill 

between  the  nuclei  and  the  white  corpuscles  in  those  animals  in  which 
the  two  organisms  exist  together  in  the  blood. 

An  opinion  somewhat  similar  to  the  above  has  been  held  by  some 
observers,  viz:  that  the  white  corpuscles  are  to  be  regarded  as  the 
"escaped  nuclei"  of  the  red  blood  corpuscles.  The  facts  adduced  to 
disprove  the  former  notion  respecting  them,  are  likewise  sufficient  to 
show  the  fallacy  of  that  just  referred  to. 

By  Dr.  Martin  Barry  the  white  corpuscles  are  considered  to  be  the 
last  stage  of  the  development  of  the  red  blood  disc,  and  he  has 
assigned  to  them  the  designation  of  "parent  cells,"  under  the  impres- 
sion that  the  granules,  of  which  many  are  contained  in  each  corpuscle, 
become  developed  into  new  blood  discs;  this  idea  of  Dr.  Barry  is 
purely  hypothetical,  and  its  accuracy  is  but  little  probable. 

Mr.  Addison  also  believes  that  the  white  corpuscles  represent  an 
advanced  condition  of  the  growth  of  the  red  blood  disc,  but  he  differs 
from  Dr.  Barry,  however,  in  not  considering  them  to  be  parent  cells, 
filled  with  young  embryos,  designating  the  white  corpuscles  "tissue 
cells,"  under  the  belief  that  they  become  incorporated  with,  and 
constitute  an  integral  portion  of  the  solid  structures  of  our  frame- work. 
The  value  of  this  theory  has  already  been  discussed. 

Mandl  denominates  the  white  corpuscles  "fibrinous  globules,"  and 
he  conceives  that  the  nuclei,  which  he  states  belong  to  all  red  cor- 
puscles of  the  blood,  as  well  as  the  white  globules,  are  not  primary 
formations,  but  secondary;  that  these  structures  do  not  exist  in  the 
blood  while  circulating  within  the  body,  but  that  they  are  formed  after 
its  abstraction  therefrom;  and  M.  Mandl  further  states,  that  the  steps 
of  the  formation  of  the  white  globules  may  be  witnessed  on  the  port 
object  of  the  microscope.  That  this  view  is  incorrect,  not  the  shadow 
of  doubt  can  be  entertained.  The  regular  form  and  size  of  the  white 
globules,  their  presence  in  the  blood  the  moment  after  their  abstraction 
from  the  system,  but  especially  the  fact  that  they  may  be  seen  in  vast 
quantities  in  that  fluid  while  still  circulating  in  the  capillaries,  all 
negative  the  idea  of  the  formation  of  the  white  globules  out  of  the 
system,  in  obedience  to  a  mere  physical  law. 

Mr.  Wharton  Jones,  in  a  recent  communication  made  to  the  Royal 
Society,  has  bestowed  upon  the  white  corpuscles  the  appellation  of 
"granule  cells,"  and  that  gentleman  considers  them  to  represent  an 
early  stage  in  the  development  of  the  red  blood  globule.  The  peculiar 
views  entertained  by  Mr.  Jones  will,  however,  be  referred  to  more 
fully  under  the  head  of  the  origin  of  the  red^lood  disc. 


112  ORGANIZED     FLUIDS. 

The  white  corpuscles  are  also  synonymous  with  the  "exudation 
corpuscles"  of  many  writers,  and  especially  of  Gerber,  who  has  under 
this  denomination  assigned  to  them  a  false  value  ;  the  presence  of  the 
white  corpuscles  in  the  plastic  fluid  of  exudations  being  rather 
accidental  than  essential. 

We  come  now  to  refer  to  the  opinion  entertained  respecting  the 
white  corpuscles  by  Muller,  who  denominated  them  "  lymph  corpus- 
cles," conceiving  them  to  be  identical  with  the  granular  corpuscles 
encountered  in  the  lymphatic  fluid.  Of  all  the  opinions  and  theories 
of  the  nature  of  the  white  corpuscles  alluded  to,  that  of  Muller  is 
probably  the  only  correct  one ;  Muller,  however,  was  not  acquainted 
with  their  existence  in  the  blood  of  mammalia,  but  merely  in  that  of 
frogs  and  other  analogous  animals. 

The  opinion  that  the  white  corpuscles  are  red  blood  globules  in  pro- 
cess of  formation,  is  one  which  is  maintained  by  many  observers,  and 
nevertheless  I  regard  it  as  erroneous.  In  the  truth  of  this  view,  Wagner, 
Baly,  Gulliver,  Professor  H.  Nasse,  and,  above  all,  Donne,  are  believers. 
From  the  excellent  work  of  the  latter  writer  I  introduce  the  following 
remarks  in  relation  to  this  point : 

"About  two  hours  after  injection  (with  milk),  rabbits,  dogs,  and 
birds  have  been  opened.  I  have  collected  the  blood  in  the  different 
organs,  in  the  lungs,  the  liver,  and  the  spleen ;  every  where  I  have 
found  the  blood  in  the  state  in  which  I  have  described  it  above, 
containing  a  certain  number  of  white  globules  in  all  stages  of  formation, 
and  of  red  globules  more  or  less  perfect :  invariably  the  spleen  has 
presented  to  me  special  circumstances  so  established  and  so  constant 
that  it  behooves  me  to  mention  them,  and  especially  since  they  may 
throw  light,  at  length,  upon  the  true  functions  of  this  organ,  so  long 
and  so  vainly  sought.  I  do  not  dare  flatter  myself  with  having  com- 
pletely resolved  this  problem,  and  it  is  but  with  reserve  that  I  express 
myself  in  this  particular. 

"The  blood  contained  in  the  large  vessels  of  the  spleen  offers 
nothing  very  remarkable ;  but,  in  expressing  that  which  is  enclosed 
and,  as  it  were,  combined  with  the  tissue  of  this  organ,  one  finds  in 
it  a  composition  well  worthy  of  fixing  the  attention.  In  a  word,  this 
blood  is  so  rich  in  white  globules,  that  their  number  approaches 
nearly  to  that  of  the  perfect  blood  globules ;  but,  further,  the  white 
globules  which  are  there,  present  in  as  evident  a  manner  all  the 
degrees  of  formation  an&  development,  and  the  examination  of  this 


THE     BLOOD.  113 

blood  does  not  appear  to  me  to  leave  any  doubt  upon  the  transition 
which  I  have  pointed  out  above  of  white  globules  to  red  corpuscles, 
and  upon  the  successive  phases  through  which  the  white  globules  pass 
to  arrive  at  the  state  of  perfect  blood  globules.  This  phenomenon  is, 
above  all,  striking,  after  injections  of  milk,  and  during  the  work, 
which  is  accomplished  in  the  space  of  four-and-twenty  hours,  of  the 
transformation  of  the  immense  quantity  of  milk  globules  into  blood 
globules.  One  cannot  believe  that  this  is  not  really  the  point — the 
laboratory,  if  one  may  so  speak — in  which  this  transmutation  is 
effected,  and  that  the  spleen  is  not  the  true  organ  of  this  important 
function.  But  I  know  how  like  facts,  and  how  the  theory  which 
results  from  them,  have  need  to  be  confirmed  by  the  researches  of 
other  observers,  to  be  definitively  adopted  with  confidence."* 

In  answer  to  these  observations  of  M.  Donne,  I  would  remark,  first, 
that  I  have  never  seen  the  different  stages  of  formation  of  the  white 
corpuscles,  and  of  transformation  of  these  into  red,  described  by  M. 
Donne ;  and,  second,  that  I  believe  that  he  has  totally  misinterpreted 
the  appearances  presented  by  blood  pressed  out  of  the  spleen.  The 
cells  or  corpuscles,  of  which  that  organ  is  itself  constituted,  so  closely 
resemble  the  white  globules  of  the  blood,  that  I  feel  assured  that  M. 
Donne  has  failed  to  discriminate  between  the  two,  and  that  many  of 
his  progressive  stages  of  development  are  to  be  referred  to  the  splenic 
cells  or  corpuscles,  numbers  of  which  are  always  contained  in  every 
drop  of  blood  procured  from  the  spleen. 

Having  now  noticed  the  various  opinions  held  by  different  observers 
in  reference  to  the  nature  of  the  white  corpuscles,  we  will  next  pass 
to  the  consideration  of  their  origin  or  mode  of  formation.  The  idea 
that  the  white  corpuscles  are  elaborated  by  the  lymphatic  glands,  has 
already  been  referred  to ;  and,  from  the  absence  of  these  glands  in  the 
lower  oviparous  vertebrata,  it  is  evident  that  they  cannot  be  regarded 
as  essential  to  their  formation. 

It  has  been  stated  that,  in  addition  to  the  white  and  red  globules, 
numerous  smaller  particles,  termed  molecules,  exist  in  the  blood. 
The  white  globules,  in  all  probability,  derive  their  origin  from  these 
molecules,  a  number  of  them  going  to  constitute  a  single  white  globule. 
This  aggregation  of  the  molecules  into  masses,  or  globules,  would 
appear  to  result  from  the  operation  of  a  general  law  of  the  economy, 
under  the  influence  of  which  the   globules   unite  with   each  other, 

*   Cours  de  Microscopie,  pp.  99,  100. 
8 


114  ORGANIZED      FLUIDS. 

and  become  invested  with  a  coating,  or  membrane,  probably  of  an 
albuminous  nature. 

Donne"  believes  also  that  he  has  traced,  by  direct  observation  and 
experiment,  the  transformation  of  the  minute  oily  and  fatty  particles, 
found  in  the  milk,  into  white  globules.  He  injected  numerous  animals, 
birds,  reptiles,  and  mammalia,  with  various  proportions  of  milk,  and, 
strange  to  say,  the  creatures  thus  experimented  upon  experienced  no 
injurious  effect  beyond  a  momentary  shock,  with,  however,  the  single 
exception  of  the  horse,  to  which  the  experiment  proved  fatal  in  seven 
different  cases.  If,  almost  immediately  after  the  injection  of  the  milk, 
a  drop  of  blood  be  withdrawn  from  the  system  at  a  distance  from  the 
point  where  the  milk  was  introduced,  a  number  of  the  globules  of  the 
milk  may  be  detected  quite  unaltered,  and  which  may  be  recognised 
by  their  general  appearance,  their  smaller  size,  and,  lastly,  by  the 
action  of  acetic  acid,  which  dissolves  the  red  globules,  renders  apparent 
the  granular  texture  of  the  white,  but  leaves  untouched  the  molecules 
of  the  milk.  If  the  blood  be  again  examined  at  about  the  expiration 
of  two  hours,  the  smallest  milk  globules  will  be  seen  to  have  united 
themselves  with  each  other  by  three's  and  four's,  and  to  have  become 
enveloped,  by  circulating  in  the  blood,  in  an  albuminous  layer,  which 
forms  around  them  a  vesicle,  analogous  to  that  which  surrounds  the 
wThite  globules.  The  largest  remain  single,  but  are  equally  enveloped 
in  a  like  covering.  These  soon  break  up  into  granules,  in  which  state 
the  milk  globules  bear  a  close  resemblance  to  the  white  globules  of 
the  blood,  from  which,  finally,  they  are  not  to  be  distinguished.  "  The 
blood,"  Donne  remarks,  "then  shows  itself  very  rich  in  white  globules ; 
but,  little  by  little,  these  undergo  modifications  more  and  more  pro- 
found; their  internal  molecules  become  effaced,  and  dissolve  in  the 
interior  of  the  vesicle,  the  globule  is  depressed,  and  soon  it  presents  a 
faint  yellow  colouration :  they  yet  resist  better  the  action  of  water 
and  acetic  acid  than  the  fully-formed  blood  globules,  and  it  is  by  this 
that  they  are  still  to  be  distinguished.  At  length,  after  twenty-four 
hours,  or,  at  latest,  after  forty-eight,  matters  have  returned  to  their 
normal  state;  no  more  milk  globules  are  to  be  found  in  the  blood,  the 
proportion  between  the  white  globules  and  the  blood  globules,  between 
the  imperfect  and  the  perfect  globules,  has  returned  to  what  it  is 
ordinarily:  in  a  word,  the  direct  transformation  of  the  milk  globules 
into  blood  globules  is  completed." 

In  the  opinion  that  the  milk  globules  are  convertible  into  the  white 
globules  of  the  blood,  Donne1  is  probably  correct,  although  it  must  be 


THE     BLOOD.  115 

an  inquiry  of  much  delicacy  and  nicety  to  determine  this  point  by 
direct  observation.  The  evidence,  however,  in  favour  of  his  latter 
position,  viz  :  that  the  white  globules  become  ultimately  converted 
into  red  corpuscles,  is  much  more  defective,  and  the  facts  upon 
which  he  relies  to  sustain  this  view  are  open  to  question,  as  we  have 
already  seen. 

The  view,  then,  of  the  transformation  of  white  corpuscles  into  red, 
I  consider  to  be  erroneous,  and  that  the  white  corpuscles,  as  they 
differ  from  the  red,  in  form,  structure,  and  chemical  composition,  so 
they  also  differ  in  origin;  and  that  the  two  forms  of  corpuscles  are 
in  every  respect  distinct,  as  well  in  function  as  in  origin. 

From  the  fact  of  the  white  corpuscles  of  the  blood  being  encoun- 
tered in  considerable  quantities  in  the  lymph  and  chyle,  which  is  in 
truth  blood  in  its  primitive  form,  it  is  in  those  fluids,  doubtless,  that 
they  take  their  origin,  and  it  is  in  them  that  they  are  best  studied. 

Origin  of  the  Red  Globules. — It  has  already  been  shown  that 
Donne  and  others  consider  that  the  red  globules  are  formed  out  of 
the,  white,  which  they  view  as  true  blood  globules  which  have  not 
reached  the  last  degree  of  elaboration.  Donne  sustains  this  opinion 
by  reference  to  the  following  particulars:  First,  that  among  the  red 
globules  contained  in  a  single  drop  of  blood,  all  are  not  affected  to  the 
same  extent  by  the  use  of  the  same  reagent;  that  some  resist  its 
influence  for  a  much  longer  period  than  others ;  Secondly,  he  states, 
that  he  has  observed  in  some  true  blood  globules  traces  of  a  slight 
punctuation,  similar  to  that  which  is  seen  in  the  white  corpuscles; 
and,  Thirdly,  in  certain  white  globules  he  has  noticed  the  compressed 
form  common  to  the  red  corpuscles.  From  the  observation  of  these 
facts,  he  draws  the  conclusion  that  the  white  globules  are  transformed 
into  red  blood  discs.  The  first  particular  alluded  to,  viz:  that  the 
same  reagent  does  not  affect  equally  all  the  red  globules  of  the  same 
blood,  is  doubtless  to  some  extent  correct,  and  may  be  explained  by 
supposing  that  the  red  corpuscles  are  not  all  of  the  same  age,  and 
therefore  are  of  different  degrees  of  consistence.  The  remarks  as  to 
the  granular  texture  of  true  blood  corpuscles,  and  the  compressed  form 
of  certain  white  globules,  it  has  never  happened  to  me  to  be  able  to 
verify  in  a  single  instance;  and,  for  my  own  part,  therefore,  I  am 
inclined  to  allow  to  them  but  very  little  weight  in  determining  the 
question  of  the  origin  of  the  red  corpuscles  of  the  blood.  To  the 
views  of  M.  Donne  on  this  point  a  high  degree  of  plausibility  and 
ingenuity  must  certainly  be  accorded ;  but  in  considering  this  question, 


116  ORGANIZED     FLUIDS. 

not  merely  the  doubtful  and  even  debateable  nature  of  the  evidence 
adduced  by  M.  Donne  must  be  taken  into  consideration,  but  also  the 
following  fact,  viz:  that  no  definite  relation  exists  in  the  animal 
kingdom  between  the  size  of  the  red  and  white  globules  compared 
together.  In  man,  and  most  mammalia,  the  white  globules  are  larger 
than  the  red  (see  Plate  I.  fig.  1);  in  most  reptiles,  and  particularly  in 
the  blood  of  the  frog,  they  are  very  much  smaller  (see  Plate  11.  fig.  1) : 
from  whence  it  would  result  that  the  process  adopted  by  nature  for 
the  conversion  of  the  white  globules  into  red,  would,  in  the  two 
classes  of  the  animal  creation  cited,  be  of  a  character  wholly  different 
the  one  from  the  other.  In  the  first-mentioned,  the  transmutation 
would  be  a  work  of  decrease ;  in  the  second,  of  increase,  or  super- 
addition  ;  and  this  supposition,  I  conceive,  would  be  tantamount  to 
charging  nature  with  the  commission  of  a  gross  inconsistency. 

There  are  other  observers,  again,  who  believe  in  the  formation  of 
the  coloured  blood  corpuscles  out  of  the  colourless  ones,  in  a  manner 
totally  different  from  that  described  by  M.  Donne. 

Thus,  Mr.  Jones,  in  a  communication  recently  made  to  the  Royal 
Society,  and  entitled  "the  Blood  Corpuscle  considered  in  its  different 
Phases  of  Development  in  the  Animal  Series,"  states  that  the  blood 
corpuscle  presents  throughout  the  animal  kingdom  at  least  two  phases 
of  development :  in  the  first  of  these,  the  corpuscle  is  granular,  and  in 
the  second,  nucleated :  when  in  the  former  phase,  it  is  denominated 
"granule  blood  cell,"  and  in  the  latter,  "nucleated  blood  cell;"  the 
first  condition,  or  that  of  granule  blood  cell,  is  synonymous  with  the 
colourless  corpuscle  of  the  blood. 

But  each  of  these  two  phases  presents  likewise  two  stages  in  their 
growth  or  formation;  thus  the  granule  blodd  cell  may  be  either 
coarsely  granular,  or  it  may  be  finely  granular ;  and  the  nucleated 
blood  cell  may  be  either  uncoloured  or  coloured.  The  first  three 
stages  are  encountered,  according  to  Mr.  Jones,  in  the  whole  animal 
series,  but  not  the  fourth  stage,  the  coloured  condition  of  the  nucle- 
ated blood  cell,  which  is  wanting  in  most  of  the  Invertebrata,  and  in 
one  of  the  series  of  Vertebrate  animals,  a  fish,  the  Br  ancliio  stoma 
lubricum  Costa;  in  all  the  other  divisions  of  the  animal  kingdom  it  is 
present,  as  in  the  Oviparous  Vertebrata  and  the  Mammalia. 

In  the  latter  class,  the  Mammalia,  a  third  phase  is  super-added  to 
the  other  two,  that  of  a  "free  cellceform  nucleus;"  this  appellation 
expresses  the  usual  condition  in  which  the  blood  disc  in  the  mammalia 
is  encountered,  and  in  which  no  nucleus  can  be  discovered. 


THE     BLOOD.  117 

This  third  phase  Mr.  Jones  considers  to  be  derived  from  the 
nucleated  blood  cell  in  its  second  stage;  the  "free  cellaeform  nucleus" 
being  the  escaped  nucleus  of  the  nucleated  blood  cell. 

The  facts  by  which  this  view  is  supported  are,  first,  a  relation  in 
size  between  the  nucleus  of  the  nucleated  blood  cell  and  the  ordinary 
blood  disc,  or  "free  cellaeform  nucleus,"  and  second,  the  occurrence, 
which  is,  however,  very  rare,  of  nucleated  cells  from  which  the  nuclei 
themselves  have  escaped. 

The  "nucleated  blood  cell"  Mr.  Jones  found  abundantly  in  the 
blood  of  an  embryo  ox,  an  inch  and  a  quarter  long ;  very  sparingly  in 
that  of  the  elephant  and  horse,  and  not  at  all  in  the  blood  of  the  human 
subject;  he  encountered  them,  however,  freely  in  the  chyle  of  man. 

Such  is  a  brief  statement  of  the  views  of  Mr.  Jones  in  reference  to 
the  blood  corpuscle,  and  of  the  chief  facts  by  which  those  views  are 
supported.  Without  taking  upon  myself  to  pronounce  upon  them 
decidedly,  I  yet  must  confess  that  they  carry  with  them  but  little 
conviction  to  my  mind,  and  that  the  facts  adduced  to  sustain  them 
are  open  to  considerable  discussion. 

If  the  blood  corpuscles  of  animals  in  general,  and  of  the  mammalia 
in  particular,  pass  through  the  successive  phases  and  stages  described 
by  Mr.  Jones,  how  happens  it,  I  would  ask,  that  in  the  blood  of  mam- 
malia, and  especially  in  that  of  man,  while  we  meet  with  so  abundantly 
the  first  stage  of  the  first  phase,  that  of  granule  blood  corpuscle,  viz : 
the  coarsely  granular  stage,  and  also  the  last  phase  indicated  by  Mr. 
Jones,  that  of  free  cellaeform  nucleus,  we  do  not  frequently  encounter 
the  intermediate  stages  and  phase,  through  which,  according  to  Mr. 
Jones,  the  blood  corpuscles  pass?  To  this  question  I  do  not  think  it 
easy  to  give  a  satisfactory  reply,  consistent  with  the  opinions  of  Mr. 
Jones.  The  explanation  which  I  would  give  of  the  absence  of  these 
transition  forms  is,  that  they  have  no  real  existence. 

According  to  Mr.  Jones,  the  nucleated  blood  cells  of  the  Oviparous 
Vertebrata  are  of  a  nature  totally  distinct  from  the  ordinary  blood 
cells  of  the  Mammalia,  which  have  no  nuclei,  but  that  the  nuclei  of 
the  blood  cells  of  the  former  are  the  analogues  of  the  latter;  this 
opinion  is  scarcely  consistent  with  the  difference  of  structure  and 
chemical  composition  observed  between  the  two.  Opinions  very 
analogous  to  those  of  Mr.  Jones  in  reference  to  the  nature  of  the 
blood  corpuscles  of  the  mammalia,  viz :  that  they  are  escaped  nuclei, 
appear  to  have  been  entertained  by  Mr.  Gulliver  from  observations 
made  on  the  horse;  this  gentleman  supposing  that  the  red  corpuscle 


118  ORGANIZED     FLUIDS. 

was  the  escaped  nucleus  of  the  white  granular  corpuscle,  while  Mr. 
Jones  conceives  that  the  red  blood  disc  is  the  liberated  nucleus  of  the 
same  body,  only  in  an  advanced  condition  of  its  development,  in  the 
stage  of  coloured  nucleated  blood  cell. 

To  the  appellations  by  which  Mr.  Jones  designates  two  of  his  phases 
of  the  development  of  the  blood  corpuscle,  an  exception  may  fairly 
be  taken.  The  "granule  blood  cell"  is  frequently  nucleated,  even 
while  it  still  retains  its  granular  structure,  and  therefore  the  term 
selected  by  Mr.  Jones  to  indicate  a  condition  of  the  blood  corpuscle 
distinct  from  its  granular  state,  viz :  that  of  nucleated  blood  cell,  is 
inappropriate,  and  calculated  to  lead  to  the  inference  that  the  granule 
blood  cell  is  not  a  nucleated  body. 

I  reiterate  then  the  opinion,  that  the  white  and  red  globules  of  the 
blood  are  wholly  distinct  from  each  other — distinct  in  origin,  in 
structure,  and  in  function. 

The  strongest  fact  with  which  I  am  acquainted  (but  it  is  one  which 
is  not  employed  by  M.  Donne)  in  favour  of  the  transmutation  of  white 
globules  into  red,  is  this,  viz :  that  the  nucleus  which  exists  in  the  blood 
discs  of  the  frog,  and  reptiles  in  general,  is  of  a  granular  structure,  in  all 
respects  similar  to  that  of  a  white  globule,  with  the  differences  only  of 
size  and  form,  the  nucleus  being  four  or  five  times  smaller  than  the  true 
white  globule,  and  of  an  oval  instead  of  a  circular  outline.  (See  Plate 
II.  fig.  5.)  One  of  these  differences,  as  already  stated — viz :  that  of  form 
— is  effaced  by  water,  which  renders  the  nucleus  circular  (see  Plate  II. 
fig.  4),  in  which  state  the  only  distinction  between  it  and  a  white  cor- 
puscle, which  can  be  detected,  is  the  single  one  of  size.  (See  Plate  II. 
fig.  1.)  This  difference,  however,  is  so  great,  and  coupled  with  the  fact 
that  no  white  globules  have  ever  been  detected  in  the  frog,  putting  on 
the  characters  of  a  true  red  blood  corpuscle,  that  the  opinion  that  the 
white  globules  are  transformed  into  red  blood  discs,  must  again  be 
abandoned.  The  existence  of  a  granular  nucleus  in  the  blood  discs  of 
reptiles,  &c,  revives  again  the  old  notion,  that  the  white  globules  are 
the  escaped  nuclei ;  that  they  are  not  so,  is  proved  by  the  fact  that  no 
such  nuclei  exist  in  the  true  blood  globules  of  man  and  the  mammalia, 
in  the  blood  of  which  white  corpuscles  abound.*     The  blood  discs,  it 

*  The  following  interesting  remarks  of  Mr.  Gulliver  tend  to  confirm  somewhat  the 
views  of  M.  Donne;  they  are  by  no  means  conclusive,  however: — "White  globules, 
about  the  same  size  as  those  in  the  blood  of  man,  and  probably  identical  with  the 
proper  globules  of  chyle  and  lymph,  are  common  in  the  blood  of  birds,  and  particu- 
larly abundant  after  a  full  meal  in  the  vultures  and  other  rapacious  families. 


THE    BLOOD.  119 

has  been  observed,  first  make  their  appearance  in  the  chyle:  any 
inquiries,  therefore,  instituted  with  the  view  of  determining  their 
origin  and  development  in  man,  would  be  more  likely  to  prove  suc- 
cessful if  directed  to  the  rigorous  examination  of  that  fluid.*' 

In  the  last  place,  it  remains  to  treat  of  the  end  or  final  destination 
of  the  red  globules  of  the  blood. 

THE    END    OR    FINAL    CONDITION    OF    THE    RED    GLOBULES. 

Every  where  throughout  the  solid  constituents  of  the  animal  organ- 
ization, cellular  tissue  abounds ;  it  forms  the  basis  of  every  texture  and 
organ  of  the  body.  It  is,  therefore,  scarcely  to  be  wondered  at  that 
the  opinion  should  have  been  adopted,  that  the  globules  which  exist 
in  such  vast  numbers  in  the  blood  were  to  be  regarded  as  the  primary 
and  even  parent  cells,  out  of  which  all  the  solid  structures  of  our 
frame  took  their  origin. f  This  theory,  to  the  mind  of  the  earlier 
micrographer,  must  have  appeared  very  rational  and  seductive;  and 
so  great,  indeed,  is  the  plausibility  with  which,  even  in  the  present 

Some  of  the  red  discs,  too,  instead  of  the  oval  form,  are  often  nearly  or  quite  circular 
in  figure.  Hence  the  blood  of  these  birds  would  appear  especially  favourable  to 
observe  any  changes  in  the  white  globules ;  and  it  seemed  highly  probable  that  these 
might  be  transformed  into  the  blood  discs  in  the  manner  mentioned  by  Dr.  Baly;  but 
although  I  made  many  observations  with  the  view  of  determining  this  question, 
nothing  but  negative  results  were  obtained." — (Appendix  to  Gerber's  General  Anato- 
my, p.  24.)  This  observation  is  satisfactory  in  one  respect,  viz :  that  it  shows  clearly 
the  connexion,  which  has  already  been  dwelt  upon,  of  the  white  corpuscles  with 
nutrition. 

*  For  further  observations  on  the  development  of  the  red  blood  disc,  see  the 
remarks  on  the  circulation  in  the  embryo  of  the  fowl. 

f  Among  those  who  regard  the  blood  corpuscles  as  cells,  may  be  named  Schwann, 
Valentin,  Addison,  Remak,  and  Barry.  Schwann  describes  the  blood  globule  as  a 
"nucleated  cell,"  while  Valentin  considers  it  to  be  a  nucleus,  and  that  which  is 
usually  held  to  be  a  nucleus  he  regards  as  a  nucleolus.  Remak  states,  that  he 
has  witnessed  the  development  of  the  globules  as  parent  cells,  not  within  the  blood, 
but  within  the  cells  which  line  the  walls  of  the  blood  vessels  and  lymphatics.  The 
views  of  Addison  are  confined  chiefly  to  the  white  globules,  which  he  conceives  to 
be  the  fully-developed  nuclei  of  the  red  blood  corpuscles,  and  which  he  believes  to 
be  transformed  into  epithelial  cells,  &c,  &c.  Dr.  Barry  goes  further  than  this;  for 
he  states  that  every  structure  which  he  has  examined  arises  out  of  the  blood  corpus- 
cle, "the  crystalline  lens  itself,  and  even  the  spermatozoon  and  the  ovum."  The 
opinions  entertained  by  Gerber  seem  to  be  of  a  nature  somewhat  similar  to  the 
foregoing.  It  is  difficult  to  understand,  however,  what  his  exact  sentiments  are:  they, 
at  all  events,  go  to  the  extent  of  supposing  that  all  the  solid  structures  of  the  body 
are  derived  from  preexisting  germs,  contained  in  the  chyle  and  blood. 


120  ORGANIZED     FLUIDS. 

day,  it  is  frequently  invested, -that  it  is  still  able'  to  claim  a  few 
adherents. 

If  we  regard  with  the  utmost  patience  and  attention  the  beautiful 
spectacle  of  the  capillary  circulation  in  any  of  the  more  transparent 
parts  of  animals,  but  especially  in  the  tongue  of  the  frog,  we  shall  in 
vain  look  for  the  escape  from  their  containing  vessels  of  even  a  single 
red  blood  corpuscle,  independent  of  a  rupture  of  those  vessels.  In  a 
normal  state,  therefore,  the  blood  globules  are  never  free,  but  are 
always  enclosed  in  their  own  proper  receptacles. 

A  communication,  however,  between  the  fluid  contents  of  the 
blood  vessels  and  the  tissues  lying  external  and  adjacent  to  them,  is 
doubtless  established,  through  the  operation  of  the  principle  of  exos- 
mosis,  whereby  a  slow  exudation  of  the  fluid  fibrin  of  the  blood  is 
perpetually  going  forward.  Now,  it  is  the  opinion  of  most  of  the 
German  physiologists,  and  it  is  the  view  best  supported  by  facts,  that 
this  fluid  fibrin  is  to  be  regarded  as  the  true  blastema,  out  of  which 
all  the  different  elementary  tissues  and  structures  of  the  body  proceed, 
and  this  not  by  any  power  inherent  in  itself,  it  being,  as  respects  the 
final  form  which  it  is  made  to  assume,  totally  inert  and  indifferent, 
and  which  form  is  impressed  upon  it  by  a  vis  insita,  or  peculiar 
power  and  faculty  belonging  to  each  organ  and  structure  of  the 
animal  fabric. 

While  the  fibrin  circulates  in  the  blood  it  retains  its  fluid  form ; 
soon  after  the  cessation  of  the  circulation,  and  whether  within  or 
without  the  system,  it  passes  from  the  fluid  state  to  the  condition  of 
a  solid.  Now,  on  the  principle  of  endosmosis,  which  has  to  be  so 
often  referred  to  in  the  explanation  of  numerous  phenomena,  in  the 
solidifying  power  of  the  fibrin,  and  in  the  vis  insita  of  the  different 
tissues,  we  recognise  the  chief  and  fundamental  causes  which  regulate 
nutrition,  growth,  and  secretion. 

It  would  thus  appear  that  the  globules  of  the  blood  (the  red  globules 
are  more  particularly  alluded  to)  are  not  to  be  regarded  as  either 
cytoblasts  or  primary  cells,  forming  by  direct  apposition  the  solids  of 
the  body,  and  that  therefore  they  do  not  express  the  last  degree  of 
elaboration  of  which  the  fibrin  of  the  blood  is  susceptible. 

Again,  then,  we  have  to  ask  ourselves  the  question,  what  is  the  end, 
or  final  condition,  of  the  red  blood  globules?  Direct  observation  is 
wanting  to  aid  us  in  the  solution  of  this  difficult  inquiry,  which, 
however,  admits  of  an  indirect  reply  being  given :  we  have  seen  that 
no  means  of  egress  from  the  blood  vessels  is,  under  ordinary  circum- 


THE     BLOOD.  121 

stances,  permitted  to  the  red  blood  globules,  and  therefore  we  are 
driven  to  the  conclusion  that,  having  performed  the  important  func- 
tion to  which  we  have  already  alluded,  viz:  that  of  carriers  of  oxygen 
from  the  lungs  throughout  the  system,  and  of  carbon  from  the  latter 
back  again  to  the  lungs,  they  become  dissolved,  increasing  by  their 
dissolution  the  amount  of  fluid  fibrin  circulating  in  the  blood,  and 
which  is  deemed  to  be  the  true  blastema. 

MOLECULES    OF    THE    BLOOD. 

In  addition  to  the  red  and  the  white  globules,  there  exists,  as  already 
mentioned,  in  the  blood  a  third  description  of  solid  constituent,  the 
"molecules:"  these  are  synonymous  with  the  "basin-shaped"  granules 
of  Vogel,  the  "globulines"  of  Donne,  and  the  "primary  discs"  of 
Martin  Barry. 

The  term  molecule,  or  granule,  is  well  suited  to  designate  these 
particles;  for  either  appellation  will  serve  to  convey  some  idea  of 
their  exceeding  minuteness,  and  which  is  computed  rarely  to  exceed 
the  30^00  °f  an  inch.  They  occur  in  great  quantities  in  the  blood, 
either  scattered  singly  throughout  it  or  agglomerated  into  small  and 
irregularly  shaped  masses.  (See  Plate  I- fig-  6.)  The  molecules  are 
usually  regarded  as  the  elements  out  of  which  the  blood  corpuscles 
are  formed  :  on  this  point,  however,  direct  observations  are  still  want- 
ing. It  is  more  probable  that  the  white  globules  are  developed  out 
of  them  than  the  red,  and  this  simply  by  their  union  or  aggregation.* 

PECULIAR    CONCENTRIC    CORPUSCLES. 

Besides  the  red  and  the  white  globules  and  the  molecules,  which 
we  have  described  as  present  in  the  blood,  a  fourth  species  of  solid 
corpuscle  has  been  observed  to  occur  in  its  fibrinous  constituent. 
These  corpuscles  have  been  repeatedly  encountered  by  Mr.  Gulliverf 
in  clots  of  fibrin  in  man  and  other  mammalia,  and  are  alike  to  be 
found  in  them,  whether  the  clots  are  formed  in  the  body  after  death, 
or  in  blood  abstracted  from  the  system  during  life. 

*  Since  the  above  few  lines  were  written  on  the  "molecules"  of  the  blood,  I  have 
repeatedly  remarked  that  in  blood,  on  its  first  abstraction  from  the  system,  but  few 
molecules  were  present,  while  in  that  which  has  been  withdrawn  from  the  body 
for  some  time,  they  have  always  abounded.  This  observation  has  led  me  strongly  to 
suspect  that  the  molecules  do  not  exist  in  the  blood  in  a  free  state,  but  that  wherever 
and  whenever  they  are  encountered,  save  only  in  the  chyle,  they  are  to  be  considered 
as  derived  from  the  rupture  and  destruction  of  the  white  corpuscles. 

f  See  translation  of  Gerber,  p.  31,  and  Appendix,  p.  16. 


122  ORGANIZED     FLUIDS. 

These  corpuscles,  of  a  very  peculiar  structure,  as  will  be  seen 
hereafter,  Mr.  Gulliver  has  described  and  figured  with  extreme  accu- 
racy;  and  he  has  styled  them  "organic  germs,"  "primary  or  nucleated 
cells,"  and  as  capable  of  further  development  if  placed  in  circum- 
stances favourable  to  their  growth.  Mr.  Gulliver,  however,  would 
appear  to  have  been  quite  undecided  as  to  their  real  nature,  and 
whether  they  were  not  to  be  regarded  as  identical  with  the  "fibrinous 
globules  "  of  Mandl. 

These  peculiar  bodies  I  have  myself  met  with  in  fibrinous  clots 
which  were  found  in  the  heart  after  death ;  and  I  have  no  hesitation 
in  asserting  that  they  differ,  in  every  essential  particular,  from  the 
fibrinous  globules  of  Mandl,  which  are  identical  with  the  colourless 
corpuscles  of  the  blood. 

The  size  of  these  corpuscles  is  subject  to  the  greatest  possible 
variation;  they  are  frequently  smaller  than  the  white  globules  of  the 
blood,  but  very  generally  three  or  four  times  larger;  their  form  is 
also  irregular,  but  inclining,  in  those  I  have  examined,  to  the  spherical. 
They  consist  of  two  parts,  of  nuclei  and  envelopes :  the  nucleus  is 
of  an  irregular  outline,  and  not  usually  well  defined  without  the  aid 
of  reagents;  its  bulk  is  about  the  one-fourth  or  one-fifth  of  that  of  the 
entire  corpuscle;  the  envelope,  in  all  the  globules  which  have  fallen 
under  my  observation,  has  been  compound,  that  is,  made  up  of  several 
vesicles  concentrically  disposed,  the  one  within  the  other.  (See 
Plate  IV.  fig.  3.) 

The  appearance  presented  by  these  objects  bears  a  close  resem- 
blance to  the  vesicles  of  certain  species  of  Algae,  of  the  genus 
Microcystis  or  Hcematococcus,  these  being  likewise  each  composed 
of  several  concentrically  arranged  membranes  or  vesicles. 

Now,  what  is  the  opinion  which  ought  to  be  entertained  in  reference 
to  the  nature  of  these  corpuscles?  Do  they  really  constitute  an 
integral  portion  of  our  organization?  and  do  they  circulate  in  the 
living  blood?  or  are  they  formed  in  it  after  death?  The  opinion  of 
Mr.  Gulliver  that  they  are  primary,  or  nucleated  cells,  has  already 
been  referred  to :  my  own  impression  as  to  them  is,  that  they  do  not 
constitute  an  integral  portion  of  our  frame;  and  that,  whether  they 
exist  in  the  living  blood,  and  circulate  in  it,  or  are  formed  in  the  clot 
subsequent  to  decease,  they  are  to  be  regarded  as  extraneous  forma- 
tions, probably  of  an  entozoal  character. 

It  does  not  appear  that  the  envelopes  of  all  the  corpuscles  met  with 
by  Mr.  Gulliver   exhibited   concentric  striae,  although  he  describes 


THE     BLOOD.  123 

some  of  them  as  possessing  this  striated  structure :  Mr.  Gulliver 
speaks  also  of  cells  three  or  four  times  larger  than  the  corpuscles,  and 
capable  of  containing  the  latter  as  nuclei.  These  I  have  not  myself 
encountered. 

The  corpuscles  are  not  usually  scattered  equally  throughout  the 
fibrinous  clot,  but  frequently  occur  in  groups,  parts  of  each  clot  being 
altogether  free  from  the  corpuscles. 

Acid  reagents,  especially  the  sulphurous  acid,  will  be  found  useful 

in  their  examination.* 

* 

BLOOD    GLOBULES    OF    REPTILES,    FISHES,    AND    BLRDS. 

The  red  globules  of  the  blood  of  the  reptile,  the  fish,  and  the  bird, 
have  all  certain  characters  in  common  with  each  other,  which  serve 
to  distinguish  them  from  those  of  man  and  the  mammalia  in  general. 
The  chief  of  these  characteristics  are  their  form,  their  size,  the 
presence  of  a  nucleus,  and,  lastly,  their  greater  consistence.  The 
compressed  form  belongs  to  the  red  blood  globules  of  all  animals ;  in 
the  three  classes  of  reptiles,  fishes,  and  birds,  however,  although  the 
globules  possess  this  flattened  figure,  instead  of  being  circular,  as  in 
man  and  the  mammalia,  they  are  in  outline  elliptical ;  and,  in  place  of 
having  a  central  depression,  this  part  of  each  globule  is  slightly  pro- 
tuberant. This  prominence  is  due  to  the  presence  of  a  nucleus, 
which  in  the  mammalia  we  have  seen  to  be  absent. 

The  size  of  the  red  globules  is  as  distinctive  as  their  form,  it  usually 
exceeding,  in  reptiles,  three  or  four  times  that  of  the  majority  of  the 
blood  corpuscles  of  mammalia.  The  blood  disc  of  the  frog  equals  in 
length  the  ttV j  of  an  inch,  while  its  traverse  measurement  is  not  less 
than  the  tgVj  °f  an  inch;  now  the  corpuscle  of  the  elephant,  the 
largest  known  among  mammalia,  reaches  only  the  stV s  °f  an  mcn  m 
diameter,  f 

It  has  already  been  remarked  that  most  of  the  animals  of  the  order 
Camelidce  are  possessed  of  blood  globules  of  an  elliptical  form,  con- 
stituting in  this  respect  an  exception  in  the  class  to  which  they 
belong.      These   oval  corpuscles  are,  however,  so  small,  that  they 

*  Since  writing  the  above  description,  I  have  met  with  these  concentric  corpuscles 
in  connexion  with  the  thymus  gland  which  had  been  allowed  to  remain  in  water  for 
a  few  hours. 

f  The  largest  blood  corpuscles  hitherto  discovered  in  the  animal  kingdom  are  those 
of  the  Siren  and  Proteus.  In  the  Siren,  according  to  Mr.  Gulliver,  the  long  diame- 
ter of  the  blood  discs  is  the  435th,  and  the  short  the  800th  part  of  an  inch,  while 
in  the  Proteus  they  are  stated  at  about  the  350th  part  of  an  inch  in  length. 


124  ORGANIZED     FLUIDS. 

could  not  be  readily  confounded  with  the  elliptical  globules  of  the 
frog,  &c. ;  they  therefore  agree  in  size,  as  well  as  in  the  absence  of  a 
nucleus,  with  the  blood  corpuscles  of  other  mammalia,  although  not 
in  form.  While  every  possible  care  has  failed  in  satisfactorily 
demonstrating  the  presence  of  a  nucleus  in  the  blood  of  mammalia, 
not  the  slightest  difficulty  is  experienced  in  detecting  it  in  that  of  the 
frog  and  most  of  the  animals  belonging  to  the  classes  just  mentioned, 
and  therefore  its  presence  is  generally  recognised ;  although  one 
excellent  observer,  M.  Mandl,  is  of  opinion  that  its  formation  takes 
'  place  subsequently  to  the  removal  of  the  blood  from  the  system :  this 
idea  is  doubtless  erroneous,  as  we  have  seen  to  be  the  case  with 
respect  to  the  white  corpuscles  of  the  blood,  regarding  which  M. 
Mandl  entertained  a  similar  notion.  In  blood  corpuscles  immersed 
in  their  own  serum,  and  examined  immediately  after  their  abstraction, 
the  nucleus  may  be  seen  with  a  sufficient  degree  of  clearness  to  enable 
the  observer  to  pronounce  with  confidence  upon  its  presence.  After 
the  lapse  of  a  few  minutes,  it  becomes  much  more  apparent,  so  that 
its  composition  is  easily  to  be  discerned:  this  arises,  most  probably, 
from  the  discharge  of  a  portion  of  the  colouring  matter  of  each 
globule.  The  form  of  the  nucleus  is  seen  to  correspond  with  that  of 
the  blood  corpuscle  itself,  and  to  be  oval,  presenting  a  granular  struc- 
ture precisely  resembling  that  of  the  white  globules  of  the  blood,  from 
one  of  which  it  is  only  to  be  distinguished  by  its  much  smaller  size 
and  oval  form.     (See  Plate  11.  fig.  2.) 

Owing  to  the  firmer  texture  and  greater  size  of  the  blood  globules 
of  the  frog,  their  structure  can  be  well  studied,  and  the  effects  of 
reagents  more  easily  determined. 

In  water,  the  red  corpuscles  lose  their  colour,  and  become  circular, 
and  indeed  globular,  a  change  of  form  which  the  nucleus  is  likewise 
seen  to  undergo.  (See  Plate  II.  figs.  3  and  4.)  These  alterations 
ensue  almost  immediately  on  the  application  of  the  water;  its  con- 
tinued action  produces  an  effect  still  more  remarkable;  the  nucleus, 
which  at  first  occupied  a  central  position  in  the  globule,  is  soon  seen 
to  become  eccentric,  and  finally,  rupturing  the  pseudo-membrane  of 
the  corpuscle,  escapes  into  the  surrounding  medium;  the  nucleus  and 
the  outer  portion  of  each  globule  are  then  observed  as  two  distinct 
structures,  lying  side  by  side  (see  Plate  II.  fig.  4) ;  the  latter  is  at 
length  absorbed,  and  then  nought  remains  but  the  nucleus,  which  is,  as 
already  remarked,  under  the  influence  of  water  rendered  of  a  globular 
form,  and  which  is  in  no  way  distinguishable  from  a  white  corpuscle 


THE     BLOOD.  125 

of  the  blood,  save  in  the  single  particular  of  size,  the  nucleus  being 
several  times  smaller  than  the  globule. 

Acetic  acid  dissolves  (if  strong,  almost  immediately)  the  outer 
tunic,  without  occasioning  the  prior  extrusion  of  the  nucleus,  the 
form  of  which  is  not  materially  affected,  the  contained  granules  merely 
becoming  more  clearly  defined.     (See  Plate  II.  fig.  5.) 

The  white  globules  in  the  blood  of  the  frog  are  very  numerous; 
they  bear  no  similitude  of  form  or  size  to  the  elliptical  red  blood  cor- 
puscles, being  usually  perfectly  spherical,  and  scarcely  more  than  a 
third  of  the  dimensions  of  the  oval  corpuscles.  Thus,  between  the 
white  globules  in  man  and  the  mammalia  and  those  of  reptiles,  an 
opposite  relation  of  size  in  reference  to  the  red  blood  discs  exists;  for 
while,  in  the  former,  the  white  corpuscles  are  larger  than  the  red 
globules,  in  the  latter  they  are  generally  much  smaller.  (See  Plate  I. 
fig.  1,  Plate II.  fig.  1.) 

The  plastic  property  possessed  by  the  blood  globules  of  all  animals 
belongs  especially  to  that  of  the  frog.  The  globules,  if  trailed  or  drawn 
along  the  surface  of  a  piece  of  glass,  may  be  elongated  to  thrice 
their  original  length,  and  made  to  assume  such  forms  as  are  altogether 
inconsistent  with  the  existence  of  a  thin  and  distinct  investing 
membrane.*     (See  Plate  II.  fig.  6.) 

CAPILLARY    CIRCULATION. 

We  have  now  considered  the  blood,  both  physiologically  and 
anatomically,  out  of  the  system,  at  rest  and  dead.  We  have,  in  the 
next  place,  to  treat  of  it  within  the  body,  living  and  circulating. 

The  beautiful  phenomenon  of  the  capillary  circulation  may  be 
witnessed  in  the  more  transparent  parts  of  several  animals;  as,  for 
example,  in  the  extremities  of  young  spiders,  fins  of  fishes,  in  the  gills 
of  the  tadpole  and  the  newt,  in  the  tail  of  the  water  newt,  in  the 
web  of  the  frog's  foot,  and  in  the  mesentery  of  the  smaller  mammalia. 
But  it  is  seen  to  the  greatest  possible  advantage  in  the  tongue  of  the 

*  The  extraordinary  elongation  of  which  the  blood  globules  of  the  frog  are 
susceptible,  may  be  seen  to  very  great  advantage  by  adopting  the  following  little- 
expedient: — A  drop  of  blood  being  placed  upon  the  object-glass  previous  to  its 
coagulation,  and  allowed  to  remain  there  for  a  few  seconds,  until  symptoms  of  con- 
solidation have  manifested  themselves,  it  is  then  to  be  extended  gently  with  two 
pins  in  opposite  directions;  if  now  the  microscope  be  brought  to  bear  upon  it, 
elongated  corpuscles  will  be  seen  in  it  in  vast  quantities.  In  the  production  of  this 
change,  it  is  the  fibrin  which  is  mainly  concerned;  for  it  is  through  it  that  the  exten- 
sion is  communicated  to  the  corpuscles. 


126  ORGANIZED     FLUIDS. 

frog;  an  organ  peculiarly  adapted  for  the  representation  of  the  cir- 
culation of  the  blood,  from  its  extraordinary  elasticity  and  transparence. 
For  a  knowledge  of  this  fact,  science  is  indebted  to  a  neighbour  and 
friend  of  mine,  Dr.  A.  Waller,  and  by  whom  it  was  communicated 
some  years  ago  to  M.  Donne.  For  the  exhibition  of  the  circulation 
in  the  tongue  of  the  frog,  in  a  satisfactory  manner,  it  is  necessary 
that  the  animal  should  be  secured  in  the  following  way : — A  bandage 
having  been  passed  several  times  around  the  body  of  the  frog,  so  as  to 
secure  effectually  the  anterior  extremities,  it  is  next  to  be  fastened  to 
a  piece  of  cork  by  additional  turns  of  the  bandage;  this  piece  of  cork 
should  be  very  thin,  six  or  seven  inches  in  length,  by  about  ten  in 
width,  and  perforated  at  one  extremity  by  a  square  aperture,  the 
diameter  of  which  should  not  be  less  than  two-thirds  of  an  inch.  To 
the  margin  of  this  aperture,  the  mouth  of  the  frog,  in  binding  it  to  the 
piece  of  cork,  should  be  brought.  The  frog  having  been  thus  effect- 
ually secured,  the  soft  and  pulp-like  tongue  should  be  drawn  out  of 
the  mouth  by  means  of  a  pair  of  forceps,  and  being  spread  over  the 
surface  of  the  aperture,  should  he  retained  in  position  by  from  four 
to  six  pins,  the  elasticity  of  the  tissue  of  the  tongue  allowing  of  its 
extension  into  a  thin  and  transparent  membrane  with  but  little  risk 
of  a  rupture  of  the  organ;  lastly,  the  piece  of  cork  should  be  fastened 
to  the  stage  of  the  microscope,  in  such  a  position  that  the  tongue 
rests  over  the  opening  in  the  stage.  These  preliminary  arrangements 
being  effected,  and  a  low  power  of  the  microscope  being  brought  to 
bear  upon  it,  a  spectacle  of  the  highest  interest  and  beauty  is  revealed 
to  the  sight  of  the  beholder.  We  have  displayed  before  us,  in  action, 
almost  every  tissue  of  the  animal  organization,  in  its  simplest  and 
clearest  form  and  disposition — arteries,  with  their  accompanying  veins 
and  nerves;  muscular  tissue;  the  blood,  with  its  red  and  white 
globules;  epithelial  cells;  glands  of  the  smallest  possible  complication 
of  structure ;  and  these  several  parts  are  not  merely  visible,  but  their 
form,  disposition,  construction,  and  normal  mode  of  action,  are  all 
distinctly  apparent ;  the  blood  ever  flowing,  the  muscles  contracting, 
and  the  glands  secreting. 

The  circulation  in  the  tongue  of  the  frog  is  best  seen,  in  the  first 
instance,  by  means  of  low  powers,  a  larger  surface  of  the  organ  being 
thus  brought  under  view,  and  a  more  exact  idea  obtained  of  .the 
relative  size  and  disposition  of  its  numerous  constituents.  The 
arteries  may  be  distinguished  from  the  veins  by  their  fewer  number, 
smaller   calibre,  and  by  the  fact  that,  while  the  veins  increase  in 


THE     BLOOD.  127 

diameter,  in  the  direction  of  the  course  which  the  blood  contained 
in  them  pursues,  the  arteries  decrease  in  the  course  which  the 
current  follows  in  them.  The  arteries,  from  their  origin,  diminish 
in  size  and  multiply  in  number,  by  the  constant  giving  off  of  second- 
ary branches ;  the  veins,  on  the  contrary,  become  enlarged  during 
their  progress,  and  lessen  in  number,  by  the  continual  addition  of 
subsidiary  veins.  These  differences,  as  well  as  the  circumstance  that 
the  velocity  of  the  blood  in  the  arteries  is  greater  than  in  the  veins, 
are  abundantly  sufficient  to  distinguish  the  two  orders  of  vessels  from 
each  other.  If,  now,  a  somewhat  higher  power  be  applied  to  the 
objects,  we  shall  be  able  to  dive  still  further  into  the  mysteries  of 
organization ;  we  shall  not  merely  perceive  the  general  motion  of  the 
blood,  but  also  that  nearly  the  entire  mass  of  that  fluid  consists  of  red 
globules.  We  shall  be  able  to  recognise  clearly  their  form,  and  to 
see  the  different  modifications  of  shape  which  they  undergo  in  passing 
by  each  other,  and  in  escaping  any  impediment  which  presents  itself 
to  impede  their  progress.  We  shall  perceive,  likewise,  that,  in  the 
smaller  capillaries,  the  globules  circulate  in  single  series,  and  mingled 
with  them  will  be  noticed  occasionally  a  colourless  globule,  which,  in 
the  blood  of  the  frog,  is  not  more  than  half  the  size  of  the  elliptical 
corpuscle.  (See  Plate  V.  fig.  2.)  Furthermore,  it  will  be  remarked 
that  the  circulation  does  not  flow  on  in  an  uninterrupted  stream  of 
equal  velocity,  but  that  certain  arrests  of  its  motion  occur.  These  are 
but  momentary,  and  after  each  the  current  again  quickly  flows  on 
with  the  same  speed  as  before ;  with  each  action  of  the  heart,  also,  a 
slight  impulsion  of  the  blood  in  the  capillaries  may  be  clearly  seen. 

This  instructive  sight  of  the  capillary  circulation  may  be  viewed 
thus  for  hours,  during  the  whole  of  which  time  the  blood  will  be  seen 
flowing  on  with  undiminished  force.  In  certain  vessels,  however, 
after  a  very  long  exposure  of  the  tongue  to  the  action  of  the  air, 
wrhereby  its  moisture  is  continually  abstracted,  and  which  acts, 
doubtless,  as  a  source  of  irritation,  a  number  of  the  colourless  globules 
will  be  seen  to  have  collected  in  the  capillaries;  these  adhere  prin- 
cipally to  the  sides  of  the  vessels  and  to  each  other,  thus  leaving 
the  channel  still  free  for  the  passage  of  the  red  globules,  which  in 
their  course  sometimes  rush  against  the  white  globules  with  such 
violence  as  to  detach  one  or  more  of  them  from  time  to  time  from  its 
adhesion  to  the  walls  of  the  vessel,  and  which,  rolling  over  once  or 
twice,  joins  the  general  current  of  the  vessel,  and  is  quickly  carried 
out   of   view.     It  would    appear   that   any  irritation    affecting   the 


128  ORGANIZED     FLUIDS. 

capillary  vessels,  even  when  applied  to  them  outwardly — as,  for 
example,  weak  chemical  solutions — gives  rise  to  the  phenomenon  in 
question.  It  is  to  be  observed,  however,  that  at  all  times  considera- 
ble numbers  of  white  corpuscles  circulate  in  the  larger  capillaries : 
these  do  not  occur  mixed  up  with  the  red  blood  corpuscles ;  but,  as 
already  remarked,  are  situated  externally  between  them  and  the  inner 
wall  of  the  capillaries.     (See  Plate  ^.fig-  1.) 

In  the  plastic  power  with  which  the  red  corpuscles  are  endowed, 
we  recognise  a  beautiful  and  important  organic  adaptation  of  matter 
to  the  fulfilment  of  a  special  purpose.  Were  it  not  for  this  plastic 
property,  and  were  the  red  corpuscles  of  the  blood,  on  the  contrary, 
of  a  solid  and  unyielding  texture,  it  would  follow,  as  an  inevitable 
consequence  of  the  solidity  of  the  globules,  combined  with  their  vast 
number,  that  frequent  interruption  and  stoppage  of  the  circulation  in 
the  capillaries  would  ensue,  and  which  would,  of  course,  result  in  the 
complete  derangement  of  the  functions  of  the  entire  economy. 

I  come  now  to  record  an  observation  which,  so  far  as  I  am  informed, 
is  without  parallel.  On  one  occasion,  in  examining  the  tongue  of  a 
frog,  a  portion  of  it  broke  away  from  the  remainder;  this  I  placed 
between  two  plates  of  glass,  and  submitted  to  examination,  when, 
extraordinary  to  say,  it  was  perceived  that  the  circulation  was  still 
vigorously  maintained  in  the  majority  of  the  vessels.  Anxious  to 
know  how  long  this  circulation  would  be  continued,  but  fully  expecting 
to  see  it  cease  every  moment,  myself  and  a  friend,  John  Coppin,  Esq., 
of  Lincoln's  Inn,  watched  it  for  upwards  of  an  hour,  at  the  end  of 
which  time  the  blood  still  flowed  onwards  in  many  of  the  vessels, 
with  scarcely  abated  vigour,  though  in  others,  often  the  larger  ones, 
the  motion  had  altogether  ceased.  The  mutilated  portion  of  the 
tongue  was  then  placed  in  water,  in  which  it  remained  during  the 
whole  of  the  night;  the  next  morning  it  was  again  examined,  when 
it  was  found  that  a  tolerably  active  circulation  still  existed  in  several 
of  the  smaller  vessels.  After  this  observation,  the  further  examination 
of  the  fragment  was  abandoned.  The  almost  immediate  cessation 
of  the  circulation,  which  occurred  in  some  of  the  larger  vessels, 
admits  of  explanation  in  the  following  way: — In  some  vessels,  the 
blood  globules  were  seen  escaping  from  their  open  extremities;  this 
effusion  of  the  globules  frequently  continued  for  two  or  three  minutes, 
until  the  entire  contents  of  such  vessels  became  poured  out,  when  of 
course  the  circulation  within  them  ceased,  the  circulating  fluid  being 
expended ;  in  other    capillaries,  the  current  was  seen  to  stop   long 


THE     BLOOD.  129 

before  their  contents  had  been  exhausted,  in  which  case  it  was  usually 
to  be  remarked  that  some  of  the  blood  corpuscles  contained  in  the 
vessels  had  collected  around  their  orifices,  thus  producing  an  impedi- 
ment to  the  further  maintenance  of  the  current. 

The  foregoing  observation  is  one  of  much  interest  and  importance; 
for  it  seems  to  prove  that  the  capillary  circulation  is  in  a  great 
measure  independent  of  vital  influences,  and  that  its  persistence  is 
mainly  due  to  physical  agencies. 

With  a  few  observations  on  the  mucous  follicles  situated  on  the 
upper  surface  of  the  tongue  of  the  frog,  we  shall  conclude  our  relation 
of  the  capillary  circulation,  as  witnessed  in  that  organ.  These 
follicles  are  glands  reduced  to  the  simplest  possible  amount  of  organ- 
ization: they  are  of  a  regularly  spherical  form,  and  transparent 
texture ;  they  are  situated  in  the  mucous  membrane  of  the  tongue,  to 
the  thickness  of  which  they  are  entirely  confined,  as  proved  by  the 
fact  that,  when  that  membrane  is  dissected  off,  by  means  of  a  needle 
the  glands  are  raised  along  with  it.  Into  each  of  these  glands  may  be 
seen  entering  it  on  one  side,  and  quitting  it  usually  on  the  opposite,  one 
of  the  smallest  of  the  capillary  vessels,  in  which  the  blood  corpuscles 
pass  usually  in  single  series;  this  vessel  in  its  passage  through  the  gland 
describes  usually  a  tortuous  course ;  and  within  it  the  blood  corpuscles 
are  seen  to  be  in  a  state  of  increased  and  incessant  activity,  appearing 
to  move,  as  it  were,  in  a  vortex,  this  appearance  resulting  from  the 
curvatures  described  by  the  vessel.     (See  Plate  VII.  jigs.  1,  2.) 

It  might  be  expected  that,  in  a  gland  of  such  simple  constitution, 
the  exact  process  of  secretion  would  be  rendered  apparent ;  in  this 
expectation,  however,  we  are  doomed  to  disappointment,  no  action 
beyond  that  which  we  have  already  related  being  visible  within  it.  An 
endosmotic  action  does  doubtless  take  place  between  the  contents  of 
the  gland  and  those  of  the  vessel  which  permeates  it,  whereby  a  peculiar 
product  is  obtained  from  the  blood,  to  be  fashioned  and  assimilated 
by  certain  powers  inherent  in  the  gland  itself,  and  the  precise  nature 
of  which  powers  is  unknown  to  us,  and  it  is  probable  that  it  never 
will  be  revealed.  Pass  we  now  to  the  description  of.  the  circulation 
in  the  embryo  of  the  chick,  which  possesses  points  of  interest  distinct 
from  those  observed  in  the  tongue  of  the  frog. 

CIRCULATION    IN    THE    EMBRYO    OF    THE    CHICK. 

The  process  by  which  the  circulation  in  the  embryo  of  the  chick 
is  displayed  is  one  which  requires  considerable  delicacy  of  manipu- 

9 


130  ORGANIZED     FLUIDS. 

lation ;  the  care,  however,  which  it  is  necessary  to  bestow  upon  it, 
for  its  successful  exhibition,  is  amply  repaid  by  the  surpassing  beauty 
of  the  spectacle  which  presents  itself  to  the  beholder.  It  is  best  seen 
in  the  third,  fourth,  and  fifth  days  of  the  incubation  of  the  egg. 

For  the  purpose  of  showing  it  satisfactorily,  the  egg  should  be  broken 
at  the  side,  and  a  portion  of  the  shell  cautiously  removed,  without  at 
the  same  time  raising  with  it  the  subjacent  membrane  (membrana 
testae) ;  this  should  next  be  peeled  off  with  the  same  degree  of  caution 
as  that  with  which  the  shell  itself  was  previously  raised. 

Immediately  beneath  this  membrane,  the  tyolk  itself  will  be  seen 
floating  in  the  midst  of  the  colourless  albumen,  and  sustained  in  posi- 
tion by  the  beautifully  spiral  chalazce,  which,  proceeding  from  the 
yolk,  are  fastened  into  that  portion  of  the  membrana  testes  which  cor- 
responds with  the  poles  of  the  egg-shell. 

Imbedded  in  the  surface  of  the  yolk  of  an  egg,  on  the  third,  fourth, 
and  fifth  days  of  its  incubation,  the  embryo  will  be  visible,  and  issuing 
from  its  umbilicus  will  be  seen  the  vessels  which  ramify  in  such 
graceful  order  through  the  membrane  of  the  allantois. 

The  embryo  is  almost  invariably  placed  uppermost  in  the  yolk,  so 
that  it  most  generally  presents  itself  beneath,  whatever  part  of  the  shell 
has  been  broken.  This  position  results  from  the  lighter  specific  grav- 
ity, and  is,  moreover,  facilitated  by  the  spiral  formation  of  the  chalazse. 

The  purposes  fulfilled  by  this  position  of  the  embryo  are  obvious 
and  striking,  it  being  thus  so  placed  as  to  receive  directly  the  caloric 
which  is  continually  emanating  from  the  parent  hen,  and  being  also 
more  immediately  submitted  to  the  influence  of  the  oxygen  of  the  air. 

In  an  embryo  then  thus  placed  in  situ,  in  the  third,  fourth,  and  fifth 
days  of  its  development,  and  with  the  unaided  sight,  the  rudiments  of 
almost  all  the  organs  and  members  may  be  clearly  recognised,  the  eye 
and  the  regular  contractions  of  the  heart,  together  with  the  vessels 
departing  from  it  to  ramify  through  the  area  vasculosa  being  particu- 
larly conspicuous.  With  a  low  power  of  the  microscope,  the  course 
of  the  blood  in  the  vessels,  together  with  the  form  and  size  of  the  white 
and  red  corpuscles,  may  be  clearly  distinguished. 

The  ramifications  of  the  vessels  in  the  area  vasculosa  present  an 
arborescent  distribution ;  their  entire  course  may  be  traced  from  their 
commencement  in  the  aorta  to  their  termination  on  the  border  of  the 
membrane  of  the  area  vasculosa. 

Now,  the  great  point  of  interest  in  the  circulation  of  the  chick  is 
that  the  passage  of  the  blood  may  be  witnessed  throughout.     Thus, 


THE     BLOOD.  131 

the  blood  expelled  from  the  heart  by  the  contraction  of  the  ventricle 
into  the  aorta,  may  be  traced  through  this  vessel,  and  all  its  subse- 
quent divisions  and  sub-divisions,  until  it  reaches  the  ultimate  arterial 
radicles,  passes  from  these  into  the  corresponding  radicles  of  the  veins, 
and  from  these  again  into  the  larger  venous  trunks,  by  which  it  is 
reconveyed  to  the  heart,  the  circle  of  the  circulation  being  thereby 
completed. 

There  are  two  ways  in  which  the  circulation  in  the  embryo  of  the 
fowl  may  be  viewed,  either  while  it  is  still  occupying  its  natural  posi- 
tion on  the  surface  of  the  yolk,  (and  this  I  think  is  by  far  the  most 
preferable  method,)  or  the  embryo  may  be  altogether  detached  from 
the  yolk  by  means  of  an  armed  needle,  and  subsequently  placed  on  a 
watch-glass  filled  with  warm  water  at  a  temperature  of  96°.  During 
the  operation  of  detaching  the  embryo,  the  egg  itself  should  also  be 
immersed  in  water  at  the  temperature  just  mentioned.  This  latter 
process  is  one,  however,  of  much  nicety,  and  frequently  fails  in  con- 
sequence of  the  rupture  of  some  of  the  finer  vessels,  the  blood  becom- 
ing effused,  the  different  parts  of  the  embryo  obscured,  and  a  stoppage 
put  to  the  circulation. 

But  it  is  not  alone  the  contemplation  of  the  circulation  in  the 
embryo  of  the  chick  which  is  so  interesting  and  instructive;  the  study 
of  the  entire  development  of  the  ovum,  from  its  commencement  to  its 
termination,  reveals  facts  of  the  highest  importance,  and  full  of  wonder. 

The  examination  of  the  blood  of  the  embryo  fowl  is  especially 
instructive,  the  mode  of  formation  of  the  red  corpuscles  admitting  of 
determination  in  a  manner  the  most  satisfactory. 

In  the  red  corpuscles  contained  in  the  blood  of  the  embryo  in  the 
first  days  of  its  development,  a  remarkable  variation  of  size  will  be 
detected,  some  of  them  being  three  or  four  times  larger  than  others, 
and  the  smallest  consisting  almost  entirely  of  a  nucleus  surrounded  by 
a  faint  and  delicate  envelope.  Between  the  two  extremes  of  size, 
every  possible  gradation  is  presented.     (See  Plate  IX.  fig.  1.) 

This  variation  in  the  dimensions  of  the  corpuscles  becomes  scarcely 
less  apparent  if  they  be  immersed  in  water,  in  which  they  become 
perfectly  spherical.     (See  Plate  IX.  fig.  2.) 

A  diversity  of  size,  almost  as  remarkable  as  that  which  exists 
between  the  red  blood  corpuscles  of  the  embryo  fowl,  will  be  observed 
also  in  those  of  the  young  frog  which  has  but  just  emerged  from  its 
tadpole  state.  If  a  drop  of  the  blood  of  this  young  frog  be  compared 
with  that  of  a  full-grown  frog,  the  corpuscles  in  the  former  will  be 


132  ORGANIZED     FLUIDS. 

remarked  to  vary  greatly  in  dimensions,  while  in  the  latter  they  will 
be  seen  to  present  a  much  greater  uniformity  of  size.  (See  Plate  IX. 
figs.  4,  5.) 

Now,  the  inferences  to  be  deduced  from  this  great  diversity  of  size 
are  palpable,  and  are,  first,  that  the  red  blood  corpuscle  is  at  its  origin 
small,  and  only  attains  its  full  dimensions  after  a  given  period ;  and, 
second,  that  the  nucleus  is  the  part  of  the  corpuscle  which  is  first 
formed,  the  coloured  investing  and  perfectly  smooth  portion  of  it  being 
gradually  developed  around  this  subsequently.  This  view  is  incon- 
sistent with  the  notion  entertained  by  many,  that  the  red  blood  cor- 
puscles result  from  the  gradual  assumption  by  the  white  globules  of 
the  characteristic  distinctions  of  the  red  blood  discs ;  for  were  this 
really  the  case,  we  should  be  at  a  complete  loss  to  account  for  the 
remarkable  differences  of  size  to  which  we  have  adverted. 

A  similar  mode  of  development  to  that  which  has  been  described  as 
belonging  to  the  red  blood  corpuscles  of  the  embryo  fowl,  appertains 
also,  I  believe,  to  that  of  all  the  Oviparous  Vertebrata. 

The  development  of  the  coloured  blood  corpuscle  of  the  Mammalia, 
I  conceive  to  agree  also  with  that  of  the  other  Vertebrata  in  the  fact 
of  its  being  small  at  first,  and  subsequently  and  gradually  attaining  its 
normal  proportions,  but  to  differ  from  that  of  the  Oviparous  Verte- 
brata in  not  being  developed  around  a  central  nucleus. 

DISSOLUTION  OF  BLOOD  CORPUSCLES. 

But  if  the  blood  of  the  embryo  fowl  is  well  adapted  for  the  study  of 
the  origin  and  development  of  red  blood  corpuscles,  that  of  the  adult 
fowl  is  no  less  fitted  for  ascertaining  their  end  and  final  destination. 

Some  observers  have  entertained  the  idea,  already  expressed  in  this 
work,  that  the  older  blood  discs  become  melted  down  in  the  liquor 
sanguinis,  and  thus,  by  their  dissolution,  increasing  the  amount  of 
fibrin  held  dissolved  in  that  liquid.  To  the  adoption  of  this  notion 
they  were  driven,  because  they  were  unable  to  dispose  of  the  red 
blood  disc  in  any  other  way,  and  which  other  facts  had  made  apparent 
to  them  could  not  be  regarded  as  persistent  structures. 

In  proof  of  the  accuracy  of  this  statement  respecting  the  melting 
down  of  the  corpuscles,  they  had  not,  however,  a  particle  of  direct 
evidence  to  adduce.  I  will  now  proceed  to  show  that  the  view  refer- 
red to  may  be  substantiated  by  positive  observation. 

In  almost  every  drop  of  the  blood  of  an  adult  fowl,  a  number  of 
certain  pale  and  usually  colourless  corpuscles  will  be  seen,  having  a 


THE     BLOOD.  133 

nucleus  of  the  same  size  and  structure  as  that  of  the  ordinary  red 
blood  disc  distinctly  visible  in  the  midst,  the  investing  portion  of  each 
corpuscle  at  the  same  time  being  invariably  smooth  and  destitute  of 
granules. 

These  corpuscles  vary  in  size,  in  form,  and  in  colour;  the  larger 
ones,  which  are  equal  in  dimensions  to  the  fully-developed  blood  discs, 
usually  retain  a  faint  colouration,  and  are  invariably  of  an  oval  form ; 
while  the  smaller  ones,  many  of  which  consist  of  merely  a  nucleus 
and  a  closely-fitting  envelope,  are  perfectly  colourless,  and  for  the 
most  part,  although  not  always,  spherical.     (See  Plate  lH-fig.  3.) 

Now,  there  is  no  difficulty  whatever  in  detecting  these  pale  and 
mostly  spherical  corpuscles  with  a  good  instrument,  nor  is  there  the 
slightest  danger  of  confounding  them  with  the  white  corpuscles,  which 
are  also  to  be  seen  retaining  their  uniformly  molecular  aspect. 

The  corpuscles  just  described  exist  not  merely  in  the  blood  of  the 
adult  fowl,  but  they  may  be  detected,  with  similar  facility,  in  every 
Oviparous  Vertebrate  animal  the  blood  of  which  I  have  examined; 
and  they  abound  in  the  blood  of  tritons  and  frogs.     (Plate  IX.  j6g\  5.) 

But  further,  there  may  be  detected  in  the  blood  of  adult  Oviparous 
Vertebrata,  not  merely  the  delicate  and  pale  corpuscles  referred  to, 
but  also  numbers  of  naked  nuclei — that  is,  of  nuclei  deprived  of  all 
trace  of  investing  membrane.     (See  Plate  IX.  figs.  3  and  5.) 

These  nuclei  should,  however,  be  examined  with  care,  and  a  nice 
adjustment  of  the  object-glass ;  for  it  will  be  found,  on  close  examin- 
ation, that  many  of  them,  though  appearing  at  first  sight  to  be  naked, 
are  not  really  so,  but  are  invested  by  a  scarcely-perceptible  envelope. 

Now,  these  large  and  slightly-coloured  oval  corpuscles,  the  smaller 
perfectly  colourless  and  mostly  spherical  ones,  and  the  naked  nuclei, 
represent  progressive  states  of  the  dissolution  of  the  red  blood  disc. 

When  first  I  noticed  these  pale  corpuscles  and  nuclei,  I  was  dis- 
posed to  think  that  they  represented  stages  in  the  upward  develop- 
ment of  the  red  blood  disc :  this  opinion  was,  however,  dispelled,  by 
observing  that  the  pale  and  colourless  corpuscles  often  exceeded 
greatly  in  size  the  smaller  true  and  coloured  blood  corpuscles. 

There  is  one  circumstance  connected  with  these  pale  corpuscles 
which  does  not  appear  to  admit  of  any  very  satisfactory  explanation, 
viz :  their  occurrence  on  the  field  of  the  microscope  in  groups. 

A  word  or  two  as  to  the  seat  or  locality  in  which  the  wTork  of 
development  of  blood  corpuscles,  and  subsequent  dissolution  of  them, 
is  conducted.     Physiologists  appear  always  to  have  been  on  the  look- 


134  ORGANIZED      FLUIDS. 

out  for  some  organ  of  the  body,  the  especial  purpose  of  which  in  the 
animal  economy  they  conceived  should  be  the  elaboration  of  the  blood 
corpuscles;  and  some  of  them,  as  Hevvson  and  Donne,  not  knowing 
well  what  office  ought  to  be  assigned  to  that  much-discussed  organ, 
the  spleen,  have  on  various  grounds  considered  it  to  be  the  laboratory 
in  which  the  work  of  development  is  carried  on.  Of  the  dissolution 
of  the  red  blood  discs,  no  definite  or  decided  observations  hitherto 
appear  to  have  been  made  by  any  observer. 

Observation  has  convinced  me  that  the  development  of  blood  cor- 
puscles is  not  assigned  to  any  particular  organ  of  the  body,  but  that  it 
occurs  within  the  blood-vessels  during  the  whole  course  of  the  circu- 
lation and  of  life.  During  the  first  formation  of  the  blood  in  early 
embryonic  life,  the  corpuscles  are  said  to  be  formed  in  the  cells, 
which  by  their  union  with  each  other  give  origin  to  the  capillary 
vessels. 

Further,  it  is  probable  that,  while  it  is  in  arterial  blood  that  the 
work  of  development  of  blood  corpuscles  is  most  active,  it  is  in  the 
venous  fluid  that  the  converse  work  of  dissolution  is  mainly  effected. 

The  development  of  blood  corpuscles  is  also  most  active  in  very 
early  life,  when  growth  is  rapid ;  and  it  is  likewise  more  active  than 
ordinary  in  adult  existence,  after  haemorrhages,  and  in  persons  of  the 
plethoric  diathesis.  In  like  manner  it  may  be  presumed  that  the  dis- 
solution of  red  blood  corpuscles  proceeds  more  quickly  in  anaemic 
conditions  of  the  system,  and  in  old  age,  while  at  the  same  time,  at 
the  latter  period,  development  of  new  corpuscles  is  more  tardy. 

It  is  now  hoped  that  a  more  satisfactory  explanation  of  the  origin 
and  end  of  the  red  blood  disc  has  been  given  than  it  was  feared,  when 
the  writer  first  approached  the  consideration  of  these  difficult,  though 
most  important,  questions,  it  would  have  been  in  his  power  to  have 
afforded. 

VENOUS   AND   ARTERIAL  BLOOD. 

Venous  and  arterial  blood  differ  in  certain  important  respects  from 
each  other;  arterial  blood  is  of  a  brighter  colour,  and  coagulates  more 
firmly  than  that  which  is  venous.  The  difference  in  colour  is  due  to 
the  presence  in  the  former  of  oxygen,  and  in  the  latter  of  carbon  in  a 
state  of  combination  not  yet  well  determined.  Venous  blood,  when 
exposed  to  the  action  of  oxygen,  soon  acquires  the  vivid  red  colour  of 
arterial  blood,  and  this,  when  submitted  to  the  influence  of  carbonic 
acid,  as  speedily  assumes  the  dark  hue  of  venous  blood. 

The  greater  or  less  firmness  in  the  clot  formed  is  owing  to  the 


THE    BLOOD.  135 

different  amount  of  fibrin  contained  in  the  two  fluids,  and  which  is 
greatest  in  that  which  is  arterial ;  the  coagulum  of  which,  therefore, 
possesses  the  greatest  density.  The  differences  detected  by  the 
microscope  in  the  blood  corpuscles  of  arterial  and  venous  blood  are 
scarcely  appreciable.  Gerber  states  that  the  "tint  of  colour  exhibited 
is  various ;  bright  in  the  globule  of  arterial  blood,  dark  red  and  some- 
what streaky  in  that  of  venous  blood  :•"  this  difference  of  colour,  which 
doubtless  exists,  it  is  easier  to  infer  than  positively  to  demonstrate  by 
means  of  the  microscope.  While  arterial  blood  is  richer  in  salts, 
venous  blood  contains  a  greater  proportion  of  fatty  matter. 

There  are  several  substances  which  effect  a  change  in  the  colour 
of  the  blood :  thus,  oxygen,  the  concentrated  solutions  of  salts  with  an 
alkaline  base,  and  sugar,  turn  dark  venous  of  a  bright  florid  or  arterial 
red ;  this  reddening  being  accomplished  by  the  salts  and  sugar,  even 
when  the  blood  is  placed  in  a  vacuum,  or  an  atmosphere  of  hydrogen, 
nitrogen,  or  carbonic  acid  gasses. 

Newbigging*  hath  also  remarked  that  venous  blood  takes  the  tint 
of  vermilion  in  a  cup,  at  those  situations  at  which  it  is  painted  with 
the  green  oxide  of  chrome ;  and  Taylorf  has  confirmed  the  observa- 
tion that  the  colours  which  contain  the  oxide  of  chrome  brighten  the 
tint  of  blood. 

On  the  other  hand,  bright  or  arterial  blood  is  darkened,  or  even 
blackened,  by  contact  with  carbonic  and  oxalic  acids,  and  by  its 
admixture,  according  to  Henle,  with  distilled  water. 

Sulphuric  acid,  and  other  acids  which  are  agitated  with  the  blood, 
change  its  colour  from  red  to  blackish  brown. 

The  nitrous  and  nitric  oxides  cause  vermilion  blood  to  take  a  deep 
purple  tint. J 

The  power  possessed  by  those  substances  which  brighten  the  colour 
of  dark  venous  blood,  is  supposed  to  be  derived  from  the  oxygen 
which  they  contain,  and  by  means  of  which  a  chemical  transforma- 
tion in  the  condition  of  the  red  element  of  the  blood,  the  hematine,  is 
effected,  a  portion  of  oxygen  being  absorbed  during  the  change  of 
colour.  Those  substances,  however,  which  cause  arterial  blood  to 
assume  the  tint  of  venous  blood,  are  presumed  to  exert  their  influence 
by  means  of  the  carbon  of  which  they  are  compounded,  and  a  portion 
of  which  becomes  imbibed  during  the  work  of  transmutation. 

*  Edinburgh  New  Philosophical  Journal,  October,  1839. 

f  Lancet,  February,  1840. 

|  Henle,  Anatomie  Generale,  tome  premier,  page  471. 


136  ORGANIZED     FLUIDS. 

Henle,  nevertheless,  considers  that  these  several  alterations  of 
colour  arise  rather  from  mechanical  than  chemical  causes,  and  that 
they  depend  upon  the  state  of  aggregation  of  the  particles  of  the 
colouring  matter,  these  being  differently  disposed  according  to  the 
nature  of  the  reagent  employed. 

Thus,  Henle  remarks*,  "  It  is  evident  that  the  colour  of  the  blood 
is  brightened  under  the  influence  of  substances  which  oppose  the  dis- 
solution of  the  hematine  in  the  serum,  and  maintain  or  reestablish  the 
flat  form  of  the  corpuscles,  as  the  concentrated  solutions  of  salts  and 
of  sugar ;  while  pure  water,  which  dissolves  the  colouring  matter,  and 
causes  the  corpuscles  to  swell,  deepens  the  colour  of  the  blood." 

Hamburgerf ,  according  to  Henle,  has  even  observed  that  weak 
solutions  of  the  chlorides  render  the  colour  of  the  blood  deeper,  while 
their  concentrated  solutions  make  it  pass  to  vermilion. 

Again,  according  to  the  observations  of  Schultz,  it  would  appear 
that  the  red  blood  corpuscles  are  flattened  by  the  action  of  oxygen, 
while  the  effect  of  the  application  of  carbonic  acid  is  to  cause  them 
to  swell  up,  and  assume  a  more  or  less  globular  figure. 

On  this  fact,  Henle  reasons  thus :  Accompanying  these  changes  of 
form  there  are  alterations  in  the  state  of  aggregation  of  the  colouring 
matter  of  the  corpuscles;  thus,  in  oxygen,  or  in  any  saline  solutions, 
the  plasma  remains  clear  and  colourless,  the  blood  discs  being  flat- 
tened, and  the  colouring  matter  contained  within  them  condensed; 
while  in  carbonic  acid  or  water  the  plasma  becomes  coloured,  by  the 
escape  of  a  portion  of  the  hematine  from  the  corpuscles,  which  swell 
up,  and  assume  a  form  approaching  more  or  less  the  globular. 

Now,  the  difference  in  colour  between  venous  and  arterial  blood 
Henle  maintains  may  be  accounted  for  by  reference  to  the  form  of 
the  corpuscles,  and  the  consequent  condition  of  the  particles  of  the 
colouring  matter. 

And  it  is  also  by  reference  to  the  state  of  the  colouring  matter  that 
Henle  accounts  for  the  fact  that  blood  which  has  once  acquired  a  very 
dark  colour  is  thereby  rendered  incapable  of  reassuming  the  bright 
hue  of  arterial  blood  on  the  application  of  oxygen  or  saline  solutions, 
because,  he  says,  that  the  pigment  which  had  escaped  into  the  plasma, 
under  the  influence  of  the  carbonic  acid,  cannot  be  made  to  enter 
into  the  corpuscles  again,  when  by  means  of  oxygen  they  are  again 
flattened. 

*Loc.  cit.  page  471. 

f  Hamburger,  Exp.  circa  Sanguinis  Coagulationem,  pp.  32.  42. 


THE     BLOOD.  137 

The  colour  of  the  blood,  then,  according  to  Henle,  depends  upon 
the  single  fact  of  the  form  of  the  corpuscle,  and  that  this  colour  is  so 
much  the  more  bright  as  these  are  flat. 

Finally,  in  support  of  his  theory,  Henle  refers  to  changes  of  colour 
presented  by  certain  inorganic  substances  from  an  alteration  in  the 
state  of  aggregation  of  its  constituent  particles:  thus,  it  is  well  known 
that  the  ioduret  of  mercury  recently  sublimed  is  yellow;  in  cooling, 
its  colour  passes  to  scarlet,  and  pressure  determines  this  change  in  an 
instantaneous  manner. 

Such  is  Henle's  mechanical  theory  of  the  changes  of  colour  expe- 
rienced by  the  blood  on  the  addition  of  reagents ;  a  theory  which, 
however  ingenious  it  may  be,  I  deem  to  be  insufficient  to  account  for 
the  very  remarkable  alterations  of  colour  to  which  the  vital  fluid  is 
subject. 

The  changes  of  colour  of  dark  blood  to  a  vermilion  hue,  and  of  this 
again  to  the  deep  tint  of  venous  blood,  admit  of  a  chemical  explana- 
tion being  given,  the  essential  element  of  the  former  change  being 
oxygen  gas,  and  of  the  latter  carbonic  acid  gas.  Thus,  even  the 
remarkable  effect  of  the  application  of  the  chlorides  may  be  accounted 
for  by  reference  to  the  well-known  operation  of  chlorine  as  a  bleach- 
ing agent,  viz :  through  the  power  which  it  possesses  of  depriving 
water  of  its  hydrogen,  and  altering  the  state  of  combination  of  the 
oxygen. 

With  respect  to  the  observations  of  Schultz  on  the  effect  of  carbonic 
acid  and  of  oxygen  in  altering  the  form  of  the  red  blood  corpuscles, 
and  on  which  fact  the  entire  of  Henle's  theory  rests,  I  would  observe 
that,  in  conjunction  with  Mr.  Miller,  the  gentleman  who  manifests  so 
much  of  patience,  skill,  and  intelligence  in  the  execution  of  the  draw- 
ings of  this  work,  and  who  is  moreover  an  excellent  chemist,  I  have 
made  many  experiments,  with  the  view  of  ascertaining  the  power 
possessed  by  the  former  reagent  in  modifying  the  form  of  the  elliptical 
corpuscles  of  the  blood  of  the  frog,  the  blood  being  in  some  cases 
submitted  to  the  direct  action  of  the  gas,  and  in  others  the  animal 
itself  being  subjected  to  its  influence. 

The  result  of  these  experiments,  on  my  mind,  is  the  conviction  that 
the  effect  of  this  gas  on  the  figure  of  the  corpuscle  is  not  appreciable. 
I  am,  therefore,  disposed  to  allow  but  little  weight  to  the  mechanical 
theory  of  the  changes  of  colour  experienced  by  the  blood. 

Venous  blood  does  not  present  precisely  the  same  tint  of  colour,  or 
the  same  characters  in  all  parts  of  the  system :  thus,  the  blood  found 


138 


ORGANIZED     FLUIDS. 


in  the  vena  portse  is  deeper  in  colour  than  any  other  venous  blood, 
and,  according  to  Schultz,  it  does  not  redden  either  on  the  application 
of  ox)Tgen  gas  or  of  salts,  and  does  not  coagulate,  or  gives  but  a  divided 
clot;  it  is  richer  in  water,  in  cruor,  and  in  fat,  and  poorer  in  albumen, 
than  ordinary  venous  blood. 

It  would  be  a  point  of  much  interest  to  determine  whether  arterial 
or  venous  blood  contains  the  greatest  number  of  blood  corpuscles. 
The  experiments  which  have  hitherto  been  made,  with  the  view  of 
determining  this  question,  are  most  unsatisfactory,  and  contradict 
each  other. 

MODIFICATION'S  OF  THE  BLOOD  CORPUSCLES  THE  RESULTS  OF  DIFFERENT  EXTERNAL  AGENCIES. 

Peculiar  Modification  of  the  Effect  of  commencing  Desiccation. 

If  the  red  corpuscles  be  examined  a  few  minutes  after  their 
abstraction  from  the  system,  in  a  drop  of  blood  which  has  been  spread 
out  between  two  plates  of  thin  glass,  it  will  be  seen  that  many  of 
them,  and  especially  those  which  are  situated  near  the  margin  of  the 
drop,  present  an  appearance  very  different  from  that  which  belongs 
to  them  in  their  ordinary  and  natural  condition.  They  now  no  longer 
exhibit  the  flattened  form  with  the  central  depression,  but  have  become 
converted  into  little  spheres,  the  surface  of  which,  instead  of  being 
smooth,  is  now  rough  and  tuberculated.  (See  Plate  I.  fig.  5.)  Blood 
corpuscles  thus  changed  have  been  compared  to  mulberries  in  appear- 
ance. This  alteration  is  supposed  by  Donne  to  depend  upon  com- 
mencing desiccation,  and  to  arise  from  deficiency  of  serum,  the 
mulberry-like  globules  being  but  imperfectly  bathed  in  that  liquid. 
No  very  satisfactory  explanation  of  the  exact  nature  of  the  change 
has  as  yet  been  given.  MjM.  Andral  and  Gavarret*  suppose  that  the 
mammillated  appearance  of  the  corpuscles  arises  from  the  adherence, 
to  the  surface  of  the  globules,  of  a  number  of  the  exceedingly  minute 
molecules  of  the  fibrin ;  this  explanation  is  probably  more  ingenious 
than  correct.  If  a  number  of  the  altered  globules  be  carefully  and 
closely  examined,  it  will  be  remarked  that  they  do  not  all  exhibit 
precisely  similar  appearances ;  that  in  some  globules,  for  instance,  it 
will  be  observed  that  the  contour  is  but  slightly  broken  or  indented ; 
that  in  others  the  indentations  of  the  surface  are  more  considerable, 
and  the  small  spaces  between  them  consequently  more  prominent; 
and  again,  in  other  globules,  and  which  are  indeed  by  far  the  most 

*  Essai  d'Hemalogie  Pathologique,  par  G.  Andral,  page  23. 


THE     BLOOD.  139 

numerous,  it  will  be  obvious  that  the  whole  surface  has  become  dis- 
tinctly tuberculated,  each  tubercle,  of  which  there  are  several  to  each 
globule,  appearing  to  be  of  a  spherical  form,  and  resembling  a  minute 
bubble  of  some  gas,  probably  of  oxygen,  or  carbon,  according  as  the 
blood  is  arterial  or  venous.  That  they  are  really  of  a  gaseous  nature 
is  proved,  I  think,  by  the  fact  of  their  gradual  formation  as  well  as 
dissipation.  M.  Andral  states,  that  in  blood  which  has  been  deprived 
of  its  fibrin,  the  corpuscles  never  exhibit  the  peculiar  granulated  or 
tuberculated  aspect  which  we  have  described ;  and  this  fact  he  adduces 
in  support  of  the  opinion  entertained  by  him,  that  this  peculiar  con- 
dition of  the  globules  is  due  to  the  accumulation  on  their  surface  of 
the  molecules  derived  from  the  fibrin. 

Mr.  John  Quekett  is  also  of  the  opinion  that  this  peculiar  condition 
of  the  blood  globules  of  which  we  have  been  speaking,  is  occasioned 
by  the  adherence  to  their  edges  of  granules  which  he  considers  to  be 
derived  from  the  interior  of  the  corpuscles  themselves.  See  "Observ- 
ations on  the  Blood  Discs  and  their  Contents,"  Microscopic  Journal, 
vol.  i.  p.  65.  For  further  observations  on  this  granulated  appearance 
of  the  corpuscles,  see  Part  I.  p.  31. 

MODIFICATIONS  THE  RESULTS  OF  DECOMPOSITION  OCCURRING  IN  BLOOD  ABANDONED  TO  ITSELF 

WITHOUT  THE  BODY. 

In  blood  abandoned  to  itself,  and  exposed  to  atmospheric  influences, 
changes  of  form  and  appearance  speedily  begin  to  manifest  themselves 
in  the  red  corpuscles.  These  changes  occur  in  regular  order;  they 
first  become  wrinkled,  deformed,  and  tuberculated;  they  next  lose 
their  flattened  and  disc-like  shape,  becoming  globular  and  smooth; 
their  colouring  matter  escapes  from  them,  and  they  present  a  livid 
hue.  In  this  condition  they  are  with  difficulty  discoverable  in  the 
blood ;  finally,  they  dissolve,  and  all  traces  of  them  disappear.  These 
successive  changes  are  all  produced  in  the  course  of  a  very  few  hours : 
the  exact  period,  however,  varies  with  the  temperature  of  the  atmos- 
phere and  actual  condition  of  the  blood  when  extracted  from  the  system. 

MODD7ICATIONS     THE     RESULTS     OF     DECOMPOSITION     OCCURRING    IN    BLOOD     WITHIN     THE 

BODY    AFTER    DEATH 

The  changes  which  we  have  described  as  occurring  in  blood 
abandoned  to  itself  without  the  system,  take  place  likewise  in  the  red 
corpuscle  of  that  which  is  contained  within  the  body  after  death,  and 
this  even  with  a  greater  degree  of  quickness  than  in  the  former  case ; 


140  ORGANIZED     FLUIDS. 

the  time,  however,  bears  a  relation  to  atmospheric  conditions,  to 
temperature,  as  well  as,  especially,  to  the  nature  of  the  malady  to 
which  the  patient  has  succumbed.  If  the  affection  which  has  occa- 
sioned death  be  of  a  nature  to  exhaust  profoundly  the  vital  powers 
— if  it  be  a  chronic  disease  of  long  duration,  as  a  typhoid  fever — the 
period  requisite  for  the  production  of  these  changes  will  be  very 
short;  so  brief,  indeed,  that  the  alterations  may  be  detected  in  the 
corpuscles  almost  immediately  after  the  extinction  of  life.  It  is  of 
much  importance  that  the  changes  resulting  from  decomposition,  and 
which  occur  in  the  dead  body,  should  not  be  confounded  with  real 
and  pathological  alterations  of  the  red  corpuscles. 

CAUSES    OF    INFLAMMATION. 

Exciting  Cause. 

The  fact  which  has  been  alluded  to  in  the  preceding  pages,  of  the 
accumulation  of  the  white  and  red  corpuscles  in  the  tongue  and  web  of 
the  frog,  as  a  consequence  of  the  application  of  irritation,  bears  a  close 
relation  to  the  phenomena  of  inflammation,  and  shows  that  the  exciting 
cause  of  inflammation,  whatever  it  may  be — such  as  a  blow,  exposure 
to  cold,  burns,  scalds,  or  the  application  of  irritating  substances — 
acts  usually  through  the  medium  of  the  nervous  system,  the  impression 
produced  on  it  impinging  upon  the  structures  to  which  the  ultimate 
nervous  nbrillee  are  distributed,  viz:  the  vessels  in  the  which  a  series  of 
results  ensue  which  together  constitute  the  condition  of  inflammation. 

Proximate  Cause. 

When  the  white  and  the  red  corpuscles  of  the  blood  accumulate 
in  the  capillaries  of  a  part  in  normal  quantity,  those  vessels  may  be 
considered  to  be  in  a  state  of  "vital  turgescence ;"  when,  however,  they 
are  present  in  those  vessels  in  abnormal  proportion,  then  the  capilla- 
ries may  be  said  to  be  in  a  state  of  "inflammatory  turgescence." 

Now,  the  term  "congestion"  indicates  a  condition  of  the  vessels 
intermediate  between  vital  and  inflammatory  turgescence,  and  which 
may  be  denominated  "  congestive  turgescence." 

In  vital  turgescence,  a  phrase  which  indicates  the  condition  of  the 
vessels  in  a  state  of  normal  nutrition,  the  capillaries  are  slightly 
increased  in  calibre,  and  are  pervaded  by  an  unusual,  though  perfectly 
normal  number  of  corpuscles,  both  red  and  white,  but  especially  of 
the  latter,  some  of  which  adhere  to  the  walls  of  the  vessels. 


THE     BLOOD.  141 

In  congestive  turgescence,  or  in  congestion,  the  calibre  of  the 
capillaries  is  more  considerably  increased  in  size,  and  a  greater  and 
abnormal  number  of  white  and  red  corpuscles,  especially  the  former, 
are  collected  in  the  vessels.  These  corpuscles,  if  the  turgescence  ter- 
minates in  resolution  without  advancing  to  the  condition  of  inflamma- 
tion, do  not  undergo  any  structural  changes,  but  enter  again  into  the 
circulation,  their  removal  being  determined  by  the  discontinuance  of 
the  exciting  cause,  and  by  the  vis  a  tergo  of  the  circulation,  which 
drives  the  corpuscles  onward. 

Lastly,  in  inflammatory  turgescence,  the  diameter  is  very  con- 
siderably enlarged,  and  their  interior  is  filled  with  a  very  greatly 
increased  and  abnormal  quantity  of  white  and  red  corpuscles,  these 
accumulating  to  such  an  extent  as  either  to  seriously  obstruct,  or 
altogether  destroy,  the  circulation  in  those  vessels.  This  condition 
of  the  vessels  is  always  accompanied  by  certain  structural  alterations, 
which  effect  not  merely  the  corpuscles  themselves,  but  also  the  vessels 
and  parts  adjacent  to  them ;  these  alterations  being  merely  attributable 
to  the  impediment  presented  to  the  onward  progress  of  the  blood  in 
the  capillaries  by  the  accumulation  in  them  of  the  blood  corpuscles. 

We  now  know  that  the  proximate  cause  of  inflammation  consists 
in  an  abnormal  accumulation  of  the  corpuscles  of  the  blood  in  the 
minute  capillary  vessels,  and  which  accumulation  we  perceive  must 
inevitably  impede  the  function  of  the  part  in  which  the  vessels  are 
thus  surcharged,  alter  its  structure,  and  finally  tend  to  a  sympathetic 
disturbance  of  the  entire  economy.  For  this  discovery  we  are 
indebted  to  the  microscope.  It  will  thus  be  seen  that  some  of  the 
ancient  hypotheses  in  reference  to  the  proximate  cause  of  inflammation 
were  not  so  very  far  wrong,  and  that  most  of  them  recognise  the 
fact,  that  it  is  the  capillary  vessels  and  blood  corpuscles  which  are 
mainly  concerned  in  the  production  of  the  phenomena  of  inflammation. 

Finally,  inflammation  may,  like  congestion,  terminate  in  resolution; 
but,  unlike  congestion,  it  always  leaves  permanent  traces  of  its 
visitation,  the  resolution  being  but  incomplete.  It  may  terminate, 
also,  in  "hepatization,"  or  in  "purulent  infiltration."  The  fibrin  of 
the  blood  is  the  chief  agent  in  producing  the  consolidation  of  the 
structure  known  by  the  term  hepatization,  while  it  is  the  white  cor- 
puscles analogous  to  those  of  the  blood,  as  will  be  seen  hereafter,  that 
give  rise  to  the  purulent  formation. 


142  ORGANIZED    FLUIDS. 

PATHOLOGY    OF    THE    BLOOD. 

We  now  come  to  the  consideration  of  the  most  important  division 
of  our  Chapter  upon  the  Blood,  viz:  that  which  treats  of  the  patho- 
logical changes  which  that  fluid  undergoes,  and  a  full  and  clear 
understanding  of  which  is  so  necessary  to  the  safe  and  successful 
treatment  of  disease. 

These  pathological  alterations  are  numerous,  and  engage  not 
merely  the  solid  constituents  of  the  blood,  the  white  and  red  corpus- 
cles, but  also  its  fluid  elements,  the  fibrin  and  the  albumen;  the 
abnormal  conditions  of  each  of  which  principles  of  the  blood  we  shall 
find  to  be  accompanied  by  a  distinct  train  of  morbid  phenomena. 
It  may  be-  said  that  the  fibrin  and  the  albumen  being  entirely  of  a 
fluid  nature,  and  not  holding  solid  particles  of  any  magnitude  in 
suspension,  they  ought  not  to  be  considered  in  a  work  devoted  to 
microscopic  anatomy.  We  shall  find,  however,  that  these  several 
constituents  of  the  blood  are  so  intimately  associated,  that,  in  order 
to  understand  any  one  of  them  fully,  it  is  necessary  that  we  should 
possess  a  knowledge  of  the  others  also,  and  therefore  I  consider  that 
their  discussion  comes  within  the  legitimate  scope  of  this  work. 

For  much  of  our  knowledge  of  the  pathology  of  the  blood  we  are 
indebted  to  the  united  researches  of  MM.  Andral  and  Gavarret,  to 
whose  valuable  essay  we  shall  have  occasion  hereinafter  to  make 
frequent  reference. 

Pathology  of  the  Red  Corpuscles  of  the  Blood. 

The  scale  of  the  red  corpuscles  of  the  blood,  relative  to  that  of  the 
other  elements,  varies  considerably,  even  in  states  of  health.  The 
mean  proportion  of  red  corpuscles  is  estimated  by  MM.  Andral  and 
Gavarret  at  127  in  every  thousand  parts  of  the  vital  fluid.  This 
scale  may,  however,  be  elevated  to  140,  or  depressed  to  110;  the 
variations  in  the  quantity  of  the  red  globules  within  these  limits  being 
compatible,  however,  with  a  physiological  or  healthy  condition  of  the 
blood,  although  the  higher  scale,  140,  is  allied  to  a  state  of  plethora, 
while  the  lower,  110,  borders  upon  the  opposite  state,  of  anaemia,  and 
both  of  which  may  be  regarded,  if  not  as  diseases  in  themselves,  at 
least  as  powerful,  auxiliary,  and  predisposing  causes  of  many  morbid 
conditions  of  the  system. 


THE     BLOOD.  143 

Increase  in  the  Number  of  the  Red  Corpuscles. — Plethora. 

An  increase  in  the  number  of  the  red  corpuscles  of  the  blood  exists 
in  that  condition  of  the  system  which  has  been  denominated  the 
plethoric,  and  which  increase  constitutes  its  chief  element.  The 
authors  already  cited  found  the  mean  proportion  of  the  red  globules 
in  the  thirty-one  cases  in  which  the  blood  was  submitted  to  examin- 
ation, to  be  in  every  thousand  parts  141 ;  the  minimum  131,  and  the 
maximum  154.  With  this  increase  in  the  number  of  the  red  cor- 
puscles, it  was  not  found  that  any  other  element  of  the  blood  had 
become  either  augmented  or  diminished. 

The  symptoms  which  indicate  the  existence  of  plethora,  whether 
they  be  organic,  or  functional  and  mental,  all  admit  of  a  ready  and 
satisfactory  explanation  by  a  reference  to  the  increased  quantity  of 
the  red  corpuscles. 

The  existence  of  a  state  of  plethora  implies  high  vital  powers ; 
there  seems  to  be  in  the  plethoric,  as  it  were  a  super-abundance  of 
life,  and  which  is  imparted  to  all  the  parts  and  organs  of  the  system 
alike.  The  plethoric  diathesis  would  appear  to  be  more  frequently 
hereditary  than  acquired,  and  no  degree  of  high  and  nutritious  feeding 
will  induce  it  in  the  system  of  some  persons,  although  an  opposite  or 
anaemic  state  may  be  produced  in  all  by  the  abstraction  of  a  proper 
quantity  of  suitable  nourishment. 

The  general  symptoms  which  characterize  the  plethoric  diathesis, 
are  a  well-developed  muscular  system,  voluminous  thorax,  a  deep- 
coloured  skin,  and  a  ruddy  complexion;  coinciding  with  these 
physical  and  outward  appearances,  we  find  much  functional  activity 
to  exist,  the  respiration  is  free  and  unembarrassed,  the  digestion  quick 
and  active,  the  pulse  is  full  and  strong,  and  the  motions  of  the  body 
are  performed  with  celerity  and  power.  This  functional  activity 
appertains  also  to  the  operations  and  emotions  of  the  mind;  the 
plethoric  is  quick  in  thought,  hasty  and  violent  in  temper. 

The  injected  skin,  the  brilliant  complexion,  are  to  be  explained  by 
reference  to  the  increased  quantity  of  the  red  corpuscles  which  cir- 
culate in  the  blood,  and  which  alone  are  the  seat  of  colour,  while  the 
great  organic  development  and  the  functional  and  mental  activity 
depend  partially  upon  the  greater  amount  of  oxygen  of  which  the 
blood  corpuscles  are  the  carriers  to  all  parts  of  the  system,  and  which 
is  so  essential  to  the  vigorous  performance  of  the  vital  processes  and 
manifestations. 


144 


ORGANIZED     FLUIDS. 


The  characters  exhibited  by  blood  which  has  been  withdrawn  from 
the  system  are  likewise  consistently  explained  by  reference  to  the 
augmented  quantity  of  the  red  blood  corpuscles ;  thus  the  blood  in 
plethora,  immediately  on  its  abstraction,  is  observed  to  be  of  a  deeper 
colour,  and  the  clot  formed  subsequently  by  its  coagulation  of  a  larger 
size ;  this,  although  voluminous,  is  of  mean  density,  and  never  exhibits 
the  buffy  coat,  which  circumstances  are  accounted  for  by  the  fact 
that,  as  already  remarked,  in  the  blood  of  plethoric  persons  there 
exists  necessarily  no  excess  of  fibrin. 

Accompanying  the  plethoric  condition,  and  dependent  upon  it,  we 
have  frequently  a  number  of  grave  pathological  manifestations,  apo- 
plexies, haemorrhages,  congestions,  vertigos,  noises  in  the  ears,  and 
flashes  of  light  before  the  eyes;  all  of  which  are  most  generally  greatly 
relieved  by  venesection,  which  withdraws  from  the  system  a  portion 
of  the  super-abundant  red  blood  corpuscles. 

Decrease  in  the  Number  of  the  Red  Corpuscles. — Ancemia. 

The  term  anaemia  indicates  a  state  of  the  system  the  very  reverse 
of  that  which  obtains  in  plethora:  in  it  the  red  blood  corpuscles, 
instead  of  being  in  excess,  are  greatly  below  the  physiological  stand- 
ard. The  authors  quoted  found,  in  sixteen  cases  of  commencing 
anaemia,  the  mean  of  the  red  globular  element  of  the  blood  to  be  109; 
and  in  twenty-four  examples  of  confirmed  anaemia,  65;  that  is,  almost 
one-half  less  than  the  standard  which  belongs  to  health.  In  one  case 
of  anaemia  in  the  human  subject,  M.  Andral  found  the  scale  to 
descend  so  low  as  28 ;  a  depression  which  one  would  scarcely  suppose 
to  be  compatible  with  life. 

In  spontaneous  anaemia  it  is  stated,  that  it  is  the  globules  alone 
which  are  affected,  and  that  in  it,  as  in  plethora,  the  other  elements 
of  the  blood  undergo  neither  augmentation  nor  diminution ;  in  acci- 
dental anaemia,  however,  resulting  from  direct  losses  of  the  vital 
fluid,  the  normal  standard  is  of  course  disturbed;  for  in  haemorrhages, 
and  especially  in  first  bleedings,  it  is  chiefly  the  globules  which  escape, 
and  this  would  lead  to  the  relatively  higher  scale  for  the  fibrin. 

As  anaemia  depends  upon  a  condition  of  the  blood  the  very  opposite 
of  that  which  exists  in  plethora,  the  symptoms  also  in  these  two 
constitutional  conditions  are  the  reverse  of  each  other;  instead  of 
the  vascular  and  injected  skin,  we  find  it  to  be  livid  and  exsanguine, 
these   appearances  extending   also  to  the   mucous  membranes;   in 


THE     BLOOD.  145 

place  of  the  accelerated  functions,  we  notice  that  the  vital  actions 
are  sluggishly  performed,  and  that  the  mental  powers  are  feeble. 

The  blood  abstracted  from  the  system  exhibits  a  paler  tint  than  is 
usual,  and  the  clot  is  small,  and  floats  in  the  midst  of  the  serum, 
which  is  very  abundant;  small,  however,  as  the  crassamentum  is, 
it  is  yet  of  considerable  density,  as  might  be  expected  from  the 
remark  which  has  already  been  made,  viz:  that  the  fibrin  exists  in  its 
normal  proportion,  and  therefore  is  in  excess  over  the  globular 
element  of  the  blood  which  is  deficient;  it  is  for  the  same  reason 
also  that  we  frequently  notice  upon  the  surface  of  the  clot  the  buffy 
coat ;  the  density  of  the  clot,  and  of  the  crust  which  covers  it,  are  so 
much  the  more  marked  as  the  anaemia  is  considerable. 

The  existence  of  the  miscalled  inflammatory  crust  in  anaemic  states 
has  long  been  known,  although  not  satisfactorily  accounted  for. 

The  pathological  disorders  to  which  anaemia  gives  origin  are 
numerous :  the  general  debility,  the  disordered  digestion,  the  difficult 
respiration,  the  palpitations  of  the  heart,  the  faintings,  are  well 
remembered. 

There  is  a  state  of  the  system,  well  described  by  Andral,  which 
stimulates  plethora,  but  which  is  really  allied  to  anaemia,  and  to 
which  the  term  false  plethora  might  be  given;  in  this  we  have  the 
injected  skin  and  many  other  indications  of  plethora;  it  is  to  be 
diagonosed,  however,  by  means  of  the  constitutional  disturbances 
which  coincide  with  those  of  ordinary  anaemia. 

It  is  in  anaemic  conditions  of  the  system  that  we  detect  the  remark- 
able bruit  de  soufflet,  in  reference  to  which  Andral  in  his  essay  on 
the  blood  has  instituted  some  useful  researches,  the  chief  result  of 
which  is  the  establishment  of  the  fact,  that  the  intensity  and  persistence 
of  the  bruit  is  in  exact  proportion  to  the  severity  of  the  anaemia. 

In  pregnancy  we  have  a  slight  example  of  an  anaemic  condition  of 
the  blood,  and  in  chlorosis  we  see  anaemia  to  prevail  with  various 
degrees  of  severity.  In  phthisis  the  scale  of  the  red  corpuscles  is 
likewise  much  reduced,  but  not  to  the  extent  to  which  its  reduction 
is  witnessed  in  chlorosis ;  and  this  is  the  more  remarkable  from  the 
circumstance  that  in  the  former  disease  it  is  those  organs  which  are 
affected,  between  which  and  the  red  corpuscles  a  close  connexion 
exists.  In  cancer  also  the  number  of  the  blood  corpuscles  is 
reduced:  in  phthisis  the  diminution  precedes  and  accompanies 
the  whole  course  of  the  affection,  while  in  cancer  it  occurs  only  at 
an  advanced  period  of  the  disease,  and  arises  principally  from  the 

10 


146  ORGANIZED     FLUIDS. 

continual  losses  of  blood  to  which  cancerous  patients  are  so  subject. 
In  disordered  states  of  the  system,  purely  nervous,  we  find  also  the 
red  element  of  the  blood  to  be  deficient.  The  scale  of  the  red  globules 
in  a  number  of  cases  in  which  the  blood  of  phthisical  patients  was 
submitted  to  examination  oscillated  between  80  and  100. 

Increase  in  the  Number  of  the  Red  Corpuscles  under  the  Influence 
of  Recovery  and  of  certain  Medicinal  Agents. 

Under  the  influence  of  recovery  the  red  blood  corpuscles  increase 
in  number,  and  have  a  tendency  to  attain  to  their  physiological 
standard,  which,  when  reached,  they  may  even  exceed,  until  at  length 
they  mount  up  to  the  scale  which  denotes  the  existence  of  the 
plethoric  condition. 

Certain  medicinal  substances  exhibit  likewise  much  influence  in 
increasing  the  number  of  the  red  corpuscles;  of  these  the  most 
remarkable  is  iron,  under  the  effect  of  which  remedy  the  pale  com- 
plexion of  the  chlorotic  will  be  seen  gradually  to  acquire  the  tone  and 
colour  indicative  of  health  and  strength. 

Effect  of  Disease  upon  the  White  Corpuscles. 

The  white  corpuscles  of  the  blood  have  not  hitherto  received  that 
amount  of  attention  which  has  been  bestowed  by  so  many  observers 
upon  their  associates  the  red  corpuscles ;  indeed,  it  is  only  in  these 
latter  times  that  their  investigation  has  been  pursued  with  that 
degree  of  care  which,  from  their  importance,  they  so  well  merit,  and 
observations  are  still  wanting  upon  their  condition  in  states  of  disease. 
It  has  already  been  remarked  that  an  increase  in  their  number  has 
been  frequently  observed  to  occur  in  various  diseases,  and  especially 
in  such  as  are  accompanied  by  suppuration  and  great  exhaustion  of 
the  vital  powers.  Of  the  precise  cause  of  this  increase,  no  very 
satisfactory  explanation  has  been  offered,  and  the  following  attempt 
at  an  explanation  is  presented  to  the  consideration  of  the  reader  with 
much  hesitation.  In  most  serious  disorders,  the  function  of  nutrition 
and  assimilation  is  more  or  less  impeded.  Now,  supposing  that  these 
white  corpuscles  are  essentially  connected  with  nutrition,  and  that 
while  the  cause  which  determines  their  formation  still  continues 
in  operation,  that  which  regulates  their  assimilation  is  suspended, 
there  would  result,  as  an  inevitable  consequence,  an  accumulation  of 
the  white  corpuscles  in  the  blood. 


THE     BLOOD.  147 

Deficiency  of  Fibrin  in  Fevers,  as  in  Typhus,  Small-pox,  Scarlatina, 

Measles. 

The  important  researches  of  MM.  Andral  and  Gavarret  establish 
the  fact,  that,  in  that  much-debated  class  of  maladies,  fevers,  there 
is  a  deficiency  in  the  blood  of  its  spontaneously  coagulable  element, 
the  fibrin.  In  the  Essai  d 'Hematologic  no  scale  of  the  diminution  in 
the  amount  of  fibrin  is  given;  it  is  shown,  however,  that  in  some 
fevers,  and  especially  in  the  commencement,  the  deficiency  of  fibrin 
may  be  but  small;  and  that  in  others,  particularly  when  symptoms  of 
putridity  have  manifested  themselves,  and  which  may  ultimately 
complicate  all  fevers,  the  loss  of  fibrin  is  considerable,  and  further 
that  the  intensity  of  symptoms  is  in  direct  relation  to  this  loss,  being 
great  when  the  diminution  of  fibrin  is  also  great. 

It  is  not  to  be  understood,  however,  that  the  deficiency  of  fibrin 
constitutes  the  essence  or  real  and  specific  cause  of  fever;  for  this 
we  must  look  to  some  other  agent  or  fact,  probably  to  the  contami- 
nation of  the  general  mass  of  the  blood  by  the  imbibition  of  some 
deleterious  and  subtle  miasma.  That  the  deficiency  in  the  amount 
of  fibrin  is  not  the  cause  of  fevers,  we  find  to  be  proved  by  the  facts 
that  this  class  of  maladies  attacks  persons  of  every  possible  variety 
of  habit  and  constitution,  and  in  many  of  whom,  at  the  onset  of  the 
disorder,  no  deficiency  of  fibrin  can  be  detected;  and  the  same  view 
is  likewise  confirmed  by  the  circumstance  which  must  have  attracted 
the  attention  of  every  physician,  viz :  that  the  primary  condition  and 
inherent  powers  of  the  system  determine  and  control  but  to  a  com- 
paratively slight  extent  the  course  which  the  malady  may  take,  and 
which  course  seems  to  be  dependent  upon  the  nature  and  quality  of 
the  infecting  agent  itself.  The  inference,  then,  which  may  be  derived 
from  the  fact  that  a  deficiency  of  fibrin  exists  in  the  blood  of  persons 
afflicted  with  fever,  is,  that  the  tendency  of  the  cause  of  fever,  a 
miasma,  or  whatever  else  it  may  be,  is  to  occasion  a  depreciation  of 
the  physiological  standard  of  the  fibrin  in  the  blood,  and  not  that  the 
deficiency  is  in  itself  the  exciting  cause  of  fever. 

Between  this  diminution  in  the  normal  proportion  of  the  fibrin  and 
the  various  hemorrhages,  which  are  so  often  observed  to  complicate 
fevers  of  all  kinds,  a  corelation  doubtless  exists,  although  the  precise 
manner  in  which  this  deficiency  leads  to  such  a  frequent  recurrence 
of  hemorrhage  is  not  clearly  understood,  and  the  only  way  in  which 


148  ORGANIZED     FLUIDS. 

this  can  be  explained  is  by  the  supposition  that  in  fevers  from  the 
cause  assigned,  viz :  the  small  quantity  of  fibrin,  the  solids  generally, 
and  the  blood-vessels  in  particular,  lose  a  portion  of  their  solidity,  and 
readily  give  way  to  the  force  of  the  fluid  contained  within  them. 

The  hemorrhages  referred  to  are  frequently  observed  in  small-pox, 
in  which  the  blood  is  effused  into  the  pustules;  in  scarlatina,  in  which 
fluxes  take  place  from  various  parts  of  the  body;  and  in  typhus,  in 
which  we-  have  frequent  buccal  hemorrhages,  and  the  formation  of 
petechiae. 

Cotemporaneous  with  this  diminution  in  the  amount  of  fibrin,  we 
do  not  find  that  any  other  element  of  the  blood  is  constantly  affected, 
although  it  occasionally  happens  that  the  red  globules  are  in  excess. 

The  clot  in  typhus,  in  which,  of  course,  the  deficiency  of  fibrin  is 
considerable,  is  large,  filling  almost  the  entire  of  the  vessel  which  con- 
tains it;  is  soft,  being  readily  broken  up  on  the  slightest  touch;  it  is 
flat,  and  ill-defined,  and  the  serum  in  which  it  floats  is  of  a  reddish 
colour. 

The  flat  form  and  softness  of  the  clot  is  to  be  explained  by  reference 
to  the  diminished  amount  of  fibrin,  while  its  great  size  is  accounted 
for  by  the  imperfect  expression  of  the  serum  from  the  crassamentum, 
as  well  by  the  fact  that  the  red  corpuscular  element  of  the  blood  exists 
usually  in  its  normal  proportion,  and  is  not  unfrequently  found  to  be 
even  in  excess. 

The  important  distinction  which  exists  between  symptomatic  or 
organic  fevers,  and  idiopathic,  or  non-organic  fevers,  is  very  essential 
to  be  borne  in  mind,  for  in  the  former  no  such  deficiency  of  the  fibrin 
exists  as  we  have  seen  to  belong  to  the  latter;  the  blood  in  inflamma- 
tory affections,  as  will  be  shown  hereafter,  exhibiting  a  state  of  its 
spontaneously  coagulable  element  the  very  reverse  of  that  which 
belongs  to  the  blood  of  idiopathic  febrile  disorders.  It  must  also  be 
recollected,  that  an  idiopathic  fever  may,  during  its  progress,  become 
complicated  with  organic  lesion,  a  circumstance  which  would  affect 
materially  the  amount  of  fibrin  in  the  blood,  its  effect  being  to  increase 
the  proportion  of  that  constituent. 

Increase  in  the  Amount  of  Fibrin  in  Inflammatory  Affections,  as  in 
Pneumonia,  Pleuritis,  Peritonitis,  Acute  Rheumatism,  SfC. 

While  in  the  class  of  febrile  disorders,  of  which  we  have  just  spoken, 
a  deficiency  of  the  fibrin  in  the  blood  exists,  in  another  series  of 
affections,  the  inflammatory,  this  element  is  found  to  be  in  excess 


THE     BLOOD.  149 

To  constitute  an  inflammation,  however,  two  "concurrent  circum- 
stances are  required;  it  is  not  alone  necessary  that  the  proportion  of 
the  fibrin  should  be  increased,  but  also  that  an  organic  lesion  should 
have  occurred,  these  two  pathological  alterations  bearing  a  close  and 
constant  relation  with  each  other. 

Since,  then,  the  spontaneously  coagulable  element  of  the  blood  in 
the  one  class  of  disorders,  viz :  fevers,  is  deficient,  while  in  the  other 
class,  inflammations,  it  is  super-abundant,  it  follows  that  the  specific 
cause  which  gives  origin  to  these  two  orders  of  maladies  operates  in 
two  opposite  directions;  its  tendency  in  the  one  being  to  diminish, 
and  in  the  other  to  augment  the  quantity  of  fibrin. 

The  law  of  the  increase  in  the  quantity  of  fibrin  in  inflammatory 
disorders  manifests  itself  under  very  remarkable  circumstances;  such, 
indeed,  as  one  would  imagine  to  be  but  little  favourable  to  its  mani- 
festation :  thus,  in  the  case  of  an  inflammation  supervening  on  typhus, 
in  which  we  have  seen  that  the  normal  scale  of  fibrin  undergoes  a 
depression,  a  disposition  to  the  augmentation  of  that  scale  will  become 
apparent.  In  the  example  of  typhus  complicated  with  local  lesion,  we 
have  two  forces  in  operation;  the  tendency  of  one  of  which  is  to 
diminish  the  amount  of  fibrin,  and  of  the  other  to  increase  that  amount; 
and  the  result  of  which  forces  operating  at  the  same  time  is  the  pro- 
duction of  a  mean  effect. 

The  proportion  of  fibrin  in  man  in  a  state  of  health  is  estimated  at 
3  parts  in  every  1000  of  the  blood.  In  a  case  of  inflammation  occur- 
ring in  the  course  of  typhus,  the  scale  was  found  to  be  h\  in  persons 
affected  with  chlorosis,  in  which  we  have  seen  that  it  is  the  globular 
element  of  the  blood  which  is  deficient,  and  attacked  with  capillary 
bronchitis,  acute  articular  rheumatism,  erysipelas,  and  pneumonia, 
the  proportion  varied  from  6  to  7  and  8;  in  acute  inflammations 
occurring  in  healthy  individuals,  it  oscillated  between  6  and  8;  and 
in  a  less  number  of  cases,  between  7  and  10.  The  highest  scale 
recorded  by  M.  Andral  is  10;  and  this  was  met  with  only  in  pneu- 
monia, and  acute  rheumatism,  while  the  lowest  was  only  4 :  this 
scale  borders  upon  that  which  is  regarded  as  normal,  and  is  encoun- 
tered only  in  sub-acute  inflammations. 

It  is  not  merely,  however,  in  pure  and  extensive  cases  of  inflamma- 
tion that  the  proportion  of  fibrin  in  the  blood  becomes  augmented, 
for  we  find  it  also  increased  in  every  organic  affection  which  is 
accompanied  by  even  a  slight  degree  of  inflammation :  thus  in  phthisis, 
at  the  period  of  the  elimination  of  the  tubercle,  as  well  as  in  cancer, 


150  ORGANIZED     FLUIDS. 

in  which  there  is  inflammation  of  those  portions  of  the  organs,  the 
seat  of  the  disease  which  immediately  surround  the  tuberculous,  or 
cancerous  deposit,  we  have  also  an  increased  amount  of  fibrin  in 
the  blood.  This  increase,  even  in  the  last  periods  of  the  disorder 
in  phthisis,  rarely  exceeds  5  parts  in  the  1000.  The  blood  in  con- 
sumption exhibits  then  not  merely  an  excess  of  fibrin,  but  also  a 
depreciation  in  the  proportion  of  its  red  element  to  the  extent  shown 
under  the  heading  AncBmia. 

There  is  one  condition  of  the  system  compatible  with  a  state  of 
health,  under  which  also  the  proportion  of  the  fibrin  in  the  blood 
is  augmented,  and  that  is  gestation.  It  is  stated,  however,  by 
M.  Andral,  that  this  increase  manifests  itself  only  in  the  three  last 
months  of  pregnancy,  previously  to  which  the  scale  of  the  fibrin  is 
found  to  be  slightly  depreciated.  This  augmentation  goes  on  increas- 
ing from  the  sixth  to  the  ninth  month,  and  is  greatest  at  the  comple- 
tion of  the  term  of  utero-gestation,  which  fact  offers  a  satisfactory 
explanation  of  the  reason  of  the  liability  to  inflammatory  attacks  on 
the  part  of  women  recently  delivered.  The  condition  of  the  blood, 
therefore,  in  the  last  periods  of  pregnancy  is  allied  to  that  state  of  the 
vital  fluid  which  is  especially  indicative  of  the  existence  in  the  system 
of  an  inflammation. 

The  characters  presented  by  the  clot  in  inflammation  are  almost 
the  reverse  of  those  which  distinguish  it  in  fevers.  It  is  of  moderate 
size,  of  firm  texture,  frequently  cupped,  and  its  surface  usually  covered 
with  the  buffy  coating  of  a  variable  thickness.  The  theory  of  the 
formation  of  this  peculiar  layer  has  already  been  entered  into,  and 
the  various  circumstances  under  which  it  has  been  encountered  have 
now  been  noticed ;  we  have  seen  that  it  occurs  in  two  very  different 
states  of  the  system,  that  it  is  present  on  the  clot  of  blood  abstracted 
in  ansemic  conditions,  as  well  as  on  that  formed  in  blood  withdrawn 
in  inflammatory  states ;  in  the  first  of  these  there  is,  in  comparison 
with  the  red  corpuscles,  a  relative  increase  in  the  proportion  of  the 
fibrin,  and  in  the  second,  a  positive  augmentation  of  that  important 
element  of  the  blood. 

The  fact  of  the  existence  of  a  super-abundance  of  fibrin  in  the  blood 
in  inflammatory  states  may  be  in  some  measure  inferred  from  the 
circumstance  of  the  escape  in  inflammation  of  a  portion  of  its  fibrin,  and 
which  doubtless  is  attended  with  a  certain  degree  of  relief  to  the  organ 
affected.  In  many  cases,  however,  it  is  not  alone  the  fibrin  which 
escapes,  and  which  is  liable  to  become  organized,  but  also  the  other 


THE     BLOOD.  151 

constituents  of  the  blood,  its  red  and  white  corpuscular  element,  (the 
latter  probably  constituting  the  pus  which  in  certain  severe  cases  is 
met  with,)  and  the  serum :  these  constituents,  however,  are  not  sus- 
ceptible of  organization,  and  are,  where  recovery  takes  place,  removed 
from  the  situation  of  their  effusion  by  absorption. 

The  discovery  of  the  fact,  that  in  inflammatory  disorders  an  excess 
of  fibrin  is  formed,  explains  the  exact  manner  in  which  blood-letting 
proves  so  serviceable,  viz :  by  removing  from  the  system  directly  a  por- 
tion of  its  super- abundant  fibrin;  so  powerful,  however,  is  the  cause 
which  determines  the  formation  of  this  excess  of  fibrin,  that  in  spite 
of  the  most  energetic  and  frequent  use  of  the  lancet,  the  scale  of  that 
element  of  the  blood  will  frequently,  and  indeed  does  generally,  ascend. 

Condition  of  the  Blood  in  Hemorrhages. 

Reference  has  been  made  to  the  frequent  occurrence  of  hemorr- 
hages in  two  very  distinct  classes  of  disorders,  the  plethoric  and  the 
febrile.  In  the  first,  we  have  seen  that  it  is  the  red  element  of  the 
blood  which  is  absolutely  in  excess  over  the  other  constituents  of  that 
fluid,  while,  in  the  second,  it  is  the  fibrin  which  is  deficient,  the 
globules  being  unaffected,  and  existing  usually  in  their  normal  pro- 
portion. Thus,  relatively  to  the  fibrin  in  both  series  of  affections,  the 
globules  are  always  in  excess,  in  reference  to  the  first  series,  the  pleth- 
oric, being  absolutely  so,  and  to  the  latter,  relatively  super-abundant. 

While  it  is  this  excess  of  the  red  globules  which  probably  deter- 
mines the  occurrence  of  hemorrhages,  the  nature  and  degree  of  these 
losses  of  blood  are  modified  by  the  amount  of  fibrin  which  that  fluid 
contains.  Thus,  the  character  of  the  hemorrhages  occurring  in 
plethoric  individuals  is  very  different  from  that  encountered  in  persons 
labouring  under  fever  in  most  of  its  forms ;  in  the  first,  we  have 
copious  epistaxes  and  the  effusion  of  blood  into  the  substance  of  the 
brain,  constituting  sanguineous  apoplexy;  in  the  second,  almost  any 
tissue  of  the  body  may  be  the  seat  of  the  effusion ;  the  blood  may  escape 
from  the  nose,  the  gums,  the  throat,  or  the  bowels,  or  it  may  be 
poured  out  beneath  the  skin  in  patches,  constituting  petechiae,  which 
we  meet  with  so  frequently  in  severe  cases  of  typhus,  and  in  scurvy. 
The  hemorrhages  to  which  the  plethoric  are  liable  are  for  the  most 
part  salutary,  while  those  which  take  place  in  fevers  are  as  generally 
prejudicial.  The  treatment  to  be  adopted  in  the  two  cases  is  very 
different ;  in  the  one,  it  may  be  necessary  to  have  recourse  to  vene- 
section, with  the  view  of  lessening  the  scale  of  the  red  globules,  and 


152  ORGANIZED     FLUIDS. 

in  the  otner,  such  a  mode  of  proceeding  would  in  all  probability  be 
fatal,  the  object  in  it  being  to  restore  to  the  blood  its  normal  proportion 
of  fibrin. 

The  distinction  which  has  here  been  dwelt  upon  between  the 
hemorrhages  to  which  the  plethoric  are  exposed,  and  those  to  which 
the  system  is  obnoxious  in  febrile  disorders  at  an  advanced  period  of 
their  attack,  corresponds  with  the  division  of  hemorrhages  into  active 
and  passive ;  the  former,  or  sthenic  type,  denoting  the  active,  and  the 
latter,  or  asthenic,  the  passive  hemorrhages. 

In  disorders  in  which  usually  we  have  no  excess  of  the  red  globules, 
but  in  which  the  fibrin  invariably  exceeds  its  usual  quantity,  as  the 
inflammatory,  and  in  affections  in  which  the  red  element  is  constantly 
deficient,  but  in  which  the  red  fibrin  retains  its  proper  proportion,  as 
in  anaemic  states,  and  especially  chlorosis,  we  find  that  hemorrhages 
are  of  very  rare  occurrence,  and  hence  again  we  are  led  to  recognise 
the  accuracy  of  the  statement,  that  the  essential  conditions  for  the 
occurrence  of  hemorrhages  are  an  excess  of  the  red  corpuscles,  as 
well  as  in  certain  cases  a  deficiency  of  the  spontaneously  coagulable 
element  of  the  bloed,  viz :  the  fibrin. 

Between  the  condition  of  the  blood,  in  which  there  is  a  deficiency 
of  fibrin,  as  in  most  fevers,  and  that  state  of  the  system  which  occupied 
so  much  of  the  attention  of  the  ancient  humeral  pathologist,  and  which 
has  been  denominated  the  putrid,  an  exact  identity  exists,  and  the 
gresrter  the  depression  in  the  scale  of  the  fibrin,  the  more  manifest 
does  the  putridity  become.  While  the  blood  is  still  circulating  within 
its  vessels,  we  can  scarcely  conceive  of  its  becoming  putrid ;  never- 
theless, so  great  in  some  cases  is  the  deficiency  of  fibrin,  and  so 
proportionate  the  consequent  tendency  to  putridity,  that  even  during 
life  certain  symptoms  indicative  of  this  condition  become  manifest,  as 
the  extreme  prostration  of  the  strength,  the  foetor  which  belongs  to  all 
the  excretions,  and  the  vital  principle  having  escaped,  the  external 
signs  of  decomposition  almost  immediately  appear. 

The  characters  of  the  blood  in  hemorrhages  scarcely  differ  from 
those  which  we  have  pointed  out  as  belonging  to  it  in  fevers ;  from 
the  small  quantity  of  fibrin,  and  the  excess  of  red  globules,  we  find 
that  the  clot  is  large,  ill-formed,  very  soft,  and  never  covered  with  the 
buffy  coating,  and  that  finally,  in  a  very  short  time,  it  undergoes 
almost  entire  dissolution,  the  only  trace  of  solid  matter  in  the  blood 
consisting  of  a  few  shreds  of  fibrin. 

There  is  one  disease,  viz:  scurvy,   in  which  a  condition  of  the 


THE     BLOOD.  ]  53 

blood,  as  regards  its  fibrin,  exists  analogous  to  that  which  character- 
izes fevers,  and  in  which  also  the  same  tendency  to  repeated  hemorr- 
hages and  to  the  formation  of  petechiae  belongs,  as  is  witnessed  in  fevers. 

It  is  a  question  for  consideration  whether  the  deficiency  of  the 
fibrin  referred  to  is  the  real  cause  of  the  proneness  of  the  blood  to 
decomposition  and  dissolution;  and  whether,  if  this  be  the  case,  there 
is  not  some  other  prior  cause  which  leads  to  and  regulates  the  extent 
of  the  diminution  of  the  physiological  standard  of  the  fibrin. 

The  experiments  of  Magendie  show  that  the  mixture  of  certain 
alkaline  substances  with  the  blood  not  merely  preserve  it  in  a  fluid  state, 
but  restore  it  to  the  fluid  form,  even  after  it  has  once  coagulated.  M. 
Magendie  injected  into  the  veins  of  living  animals  a  certain  quantity 
of  a  concentrated  solution  of  the  sub-carbonate  of  soda,  and  found  that 
in  the  dead  bodies  of  these  animals  the  blood  was  almost  entirely  in  a 
fluid  state,  and  that  even  during  life  they  presented  many  of  the 
symptoms  which  are  acknowledged  to  denote  a  state  of  dissolution  of 
the  blood. 

The  alkaline  condition  of  the  blood  in  scurvy,  in  which  the  prone- 
ness to  hemorrhage  is  so  great,  is  well  known. 

A  fluid  state  of  the  blood  is  said  to  exist  in  those  who  have  died 
from  the  bite  of  serpents,  and  it  is  most  probable  that  in  like  manner 
the  effect  of  the  imbibition  of  a  poisonous  miasma  is  to  cause  the 
blood  to  retain  its  fluidity. 

The  deplorable  effects  which  sometimes  ensue  from  a  dissection- 
wound  are  most  probably  due  to  the  entrance  into  the  blood  of  a 
poisonous  matter,  and  in  fatal  cases  we  have  all  the  signs  indicative 
of  a  dissolution  of  the  blood. 

It  is  likewise  asserted,  that  any  violent  impression  made  on  the 
nervous  system,  either  through  the  influence  of  some  strong  moral 
emotion,  or  as  the  result  of  a  blow,  especially  on  the  pit  of  the  stomach, 
an  electric  shock,  as  of  lightning,  retards,  or  altogether  prevents,  the 
coagulation  of  the  blood,  while  at  the  same  time  it  destroys  life.  That 
the  same  effect  is  likewise  produced,  though  in  a  manner  less  obvious 
and  less  sudden,  by  the  slow  and  continued  operation  of  any  cause 
which  depresses  the  power  of  the  nervous  influence,  so  as  at  length 
to  effect  the  health  prejudicially,  cannot  be  doubted. 

The  proneness  of  children  to  hemorrhages,  their  liability  to  febrile 
disorders,  and  the  difficulty  of  restraining  the  bleeding  which  flows 
from  any  breach  of  continuity  which  the  skin  may  have  suffered, 
especially  that  of  a  leech-bite,  in  infants,  are  well  known.     The  state 


154  ORGANIZED     FLUIDS. 

of  the  blood  in  children  is  not  commented  upon  by  the  talented 
authors  to  whom  we  have  had  such  frequent  occasion  to  refer  in  their 
important  pathological  essay  on  the  blood;  it  is  most  probable, 
however,  that  while  its  globular  element  is  somewhat  in  excess,  that 
in  fibrin  it  is  equally  deficient. 

With  one  other  remark  we  will  bring  this  short  chapter  on  hemorr- 
hage to  a  conclusion,  and  proceed  in  the  next  place  to  consider  the 
effect  produced  upon  the  economy  by  the  deficiency  of  another  element 
of  the  blood.  The  statistical  and  historical  details  of  epidemics  clearly 
prove  that  those  dire  forms  of  disease,  of  which  extensive  and  alarm- 
ing hemorrhages  were  such  frequent  complications,  have  in  these 
latter  times  become  much  more  rare.  This  happy  result  is  doubtless 
due  to  the  advances  made  in  the  arts  and  sciences,  and  to  their  more 
extensive  application  in  the  improvement  of  the  hygienic  condition  of 
mankind. 

Decrease  in  the  Normal  Proportion  of  Albumen. 

It  is  now  generally  known,  that  the  majority  of  cases  of  dropsy 
depend  upon  a  pathological  alteration  of  some  solid  organ  of  the  body, 
as  the  heart  and  the  liver;  most  persons  are  also  aware  of  the  fact 
that  other  cases  of  dropsy  occur,  which  do  not  arise  from  any  such 
morbid  organic  condition,  but  have  their  origin,  according  to  MM. 
Andral  and  Gavarret,  in  a  pathological  degeneration  of  one  of  the 
elemental  constituents  of  the  blood. 

In  the  dropsy  which  attends  the  advanced  stages  of  the  affection 
known  by  the  name  of  Bright's  disease  of  the  kidney,  in  that  which 
supervenes  upon  scarlatina,  in  hydropsies  arising  from  insufficient  and 
improper  diet,  as  well  as  in  those  which  occasionally  follow  suddenly 
suppressed  perspiration,  it  has  been  observed  that  the  urine  is  always 
albuminous,  and  the  writers  just  mentioned  have  ascertained  the 
existence  of  a  fact  which  stands  in  close  relation  with  the  albuminous 
excess  in  the  urine  in  the  instances  enumerated,  viz :  that  the  blood 
is  itself  in  these  cases,  on  the  contrary,  deficient  in  albumen.  Trie 
knowledge  of  these  two  facts,  therefore,  and  the  observation  that  their 
occurrence  is  so  generally  associated  with  dropsical  effusion,  has  led 
MM.  Andral  and  Gavarret  to  entertain  the  opinion  that  a  close  con- 
nexion exists  between  the  deficiency  of  albumen  in  the  blood  and 
the  forms  of  dropsy  alluded  to,  and  which  is  probably  that  of  cause 
and  effect. 

In  speaking  of  non-organic  dropsies  it  has,  until  recently,  been  con- 


THE    BLOOD.  155 

ceived  sufficient  to  say  that  they  depended  as  a  cause  upon  impover- 
ishment of  the  blood ;  but  this  expression  we  now  know  to  be  vague, 
inasmuch  as  it  does  not  convey  any  exact  notion  of  the  real  changes 
which  the  blood  may  have  undergone:  we  have  seen  that  the  blood 
may  be  rich  in  its  red  globules  or  in  its  fibrin,  and  also  that  it  may  be 
poor  in  these  elements  in  almost  every  proportion  and  degree.  Let 
us  see  whether  a  deficiency  of  either  of  the  two  constituents  just 
named  predisposes  to  dropsies.  In  anaemic  states,  and  in  chlorosis 
especially,  we  have  an  impoverished  state  of  the  blood,  and  in  these 
we  know  that  it  is  the  red  corpuscles  which  are  deficient;  and  yet 
daily  experience  shows  us  that  dropsy  in  such  states,  and  particularly 
in  chlorosis,  even  in  its  most  severe  forms,  is  a  very  rare  termination. 
In  febrile  disorders  again,  we  have,  for  the  most  part,  an  impoverished 
condition  of  the  blood,  arising  from  the  depression  in  the  scale  of  the 
fibrin,  and  yet  of  these  we  do  not  find  dropsical  effusion  to  be  by  any 
means  a  frequent  result. 

It  is  not  excess  of  water  in  the  blood  which  gives  rise  to  dropsy, 
for,  if  that  were  the  case,  then  would  it  frequently  occur  in  the  dis- 
order to  which  we  have  referred,  chlorosis,  in  which  a  greater 
proportion  of  water  than  is  ^normal  exists  in  the  blood. 

The  causes  of  impoverishment  of  the  blood  enumerated  therefore 
do  not  act  as  exciting  causes  of  dropsy :  there  remains  but  one  other 
element  of  the  blood,  the  albumen,  for  our  consideration,  and  this  we 
have  seen  to  be  constantly  deficient  in  the  blood  in  certain  forms  of 
dropsy,  and  we  are  therefore  constrained  to  adopt  the  conclusion  that 
this  depreciation  in  the  scale  of  the  albumen  is  intimately  associated 
with  the  occurrence  of  those  forms. 

It  does  not  appear,  according  to  M.  Andral,  that  the  albumen  can 
undergo  a  spontaneous  depreciation  in  the  blood,  similar  to  that  of  which 
we  have  seen  that  the  red  globules  and  the  fibrin  are  susceptible ;  this, 
if  correct,  is  very  remarkable,  and  hence  it  would  follow  that  when- 
ever a  deficiency  of  the  albumen  of  the  blood  exists,  invariably,  at  the 
same  time,  the  urine  would  be  found  to  be  albuminous,  provided 
always  that  no  dropsical  effusion  existed,  the  effect  of  some  organic 
malady. 

In  most  organic  dropsies  the  diseased  organs  act  as  exciting  causes 
of  the  serous  effusion  by  the  mechanical  impediment  which  their  altered 
structure  and  enlarged  size  present  to  the  circulation  in  the  vessels, 
and  which,  therefore,  relieve  themselves  by  permitting  the  escape  of 
a  portion  of  their  contents.     In  Bright's  disease,  although  the  kidney 


156  0RGAE1ZED     FLUIDS. 

is  affected,  that  organ  does  not  concur  in  the  formation  of  the  dropsy, 
except  in  a  manner  altogether  indirect,  and  to  such  an  extent  only,  as 
that  the  pathological  alteration  which  its  substance  undergoes  is  of 
such  a  nature,  as  to  afford  greater  facility  to  the  passage  of  the 
albumen  through  it. 

The  serosity  effused  in  cases  of  dropsy  is  not  identical  in  its  con- 
stitution with  the  serum  of  the  blood ;  it  contains  usually  far  less  of 
the  inorganic  constituents  which  are  held  in  solution  in  healthy  serum, 
as  well  as  a  far  less  proportion  of  albumen,  than  that  which  belongs 
to  serum  in  its  normal  state.  The  physiological  standard  of  the 
albumen  in  the  blood  is  eighty  in  every  thousand  parts ;  in  sixteen 
cases  in  which  the  serous  effusion  was  analyzed  by  M.  Andral,  the 
scale  was  found  to  oscillate  between  48  and  4,  these  two  numbers 
representing  the  highest  and  the  lowest  proportions.  In  six  cases  of 
hydrocele,  the  amount  of  albumen  was,  as  represented  in  the  following 
figures,  59,  55;  two  of  51 ;  49,  35.  It  should  be  remarked  that  none 
of  these  analyses  refer  to  cases  of  dropsy  connected  with  excess  of 
albumen  in  the  urine.  It  would  be  interesting  to  ascertain  the  amount 
of  the  albuminous  element  contained  in  the  serum  effused  in  such  cases. 

MM.  Andral  and  Gavarret  state  that  they  did  not  find  that  either 
the  cause  of  the  hydropsy,  or  its  seat,  excited  any  influence  over  the 
quantity  of  albumen  of  the  effused  serum;  but  they  remarked  that  the 
amount  did  in  some  degree  depend  upon  the  condition  of  the  consti- 
tution, and  that  the  more  robust  its  state,  the  greater  the  proportion 
of  the  albumen:  in  this  way  the  higher  scale  exhibited  in  the  six  cases 
of  hydrocele  may  be  accounted  for,  their  occurring  in  persons  all  of 
whom  were  young  and  strong ;  and  thus,  also,  the  great  depression 
of  that  scale  may  be  explained  in  those  whose  constitutions  have  been 
weakened  by  repeated  tappings. 

Two  explanations  may  be  given  of  the  reason  why  blood  less  rich 
than  ordinary  in  albumen  should  give  rise  to  serous  effusion.  The 
first  is,  that  the  abstraction  of  the  albumen  may  alter  the  density  of  the 
serum,  and  thus  permit  more  readily  its  escape  through  the  walls  of 
the  vessels;  the  second  is,  that  blood  deprived  of  its  albumen  becomes 
less  yielding,  and  so  glides  less  easily  along  the  walls  of  the  capillary 
vessels,  thus  occasioning  in  them  an  obstruction  to  the  circulation 
and  consequent  effusion  of  serum.  Of  these  explanations,  the  former 
is  perhaps  the  more  probable. 

The  proportion  of  water  in  all  serous  effusion  is,  of  course,  con- 
siderable,   and   is  greatest  in  those  cases   in  which    there   is   least 


THE     BLOOD.  157 

albumen.  The  mean  proportion  of  water  in  the  serum  of  the  blood 
is  790  in  1-000  parts ;  in  the  fluid  of  dropsies  the  highest  scale  hitherto 
observed  is  986,  and  the  lowest  930. 

The  fluids  effused  in  burns  and  scalds,  and  as  the  result  of  the 
application  of  a  blister,  and  which  are  always  preceded  by  some 
degree  of  inflammation,  are  also  rich  in  albumen.  The  very  curious 
observation  is  made  by  M.  Andral,  that  in  cases  where  dropsical 
effusion  exists  in  more  than  one  situation  in  the  same  individual,  that 
in  each  locality  the  fluid  effused  may  exhibit  a  very  different  propor- 
tion of  albumen.  Thus,  in  a  woman  attacked  with  an  organic 
affection  of  the  heart,  there  were  thirty  parts  of  albumen  in  the  fluid 
of  the  pericardium,  while  there  were  but  four  parts  in  the  serosity  of 
the  cellular  tissue  of  the  inferior  extremities. 

In  having  thus  ascertained  the  different  modifications  in  quantity 
which  the  three  great  elements  of  the  blood  may  undergo — the  globules, 
the  fibrin,  and  the  albumen — it  yet  must  be  confessed  that  the  patho- 
logical history  of  the  blood  is  still  very  far  from  being  rendered  com- 
plete. It  is  more  than  probable  that  rigorous  chemical  analysis  will 
disclose  the  fact,  that  the  several  extractive  as  well  as  inorganic 
substances  which  exist  in  the  blood,  vary  greatly  in  amount  in  the 
numerous  disorders  to  which  the  human  body  is  liable.  From  the 
great  quantity  of  these  substances  which  are  found  in  the  urine,  it 
would  appear  that  the  grand  purpose  fulfilled  in  the  economy  by  this 
excretion  is  that  of  regulating  their  amount  in  the  blood,  and  of 
reducing  it  to  a  standard  consistent  with  a  physiological  condition  of 
the  system. 

Into  this  branch  of  the  pathology  of  the  blood  inquirers  have  as  yet 
scarcely  entered ;  and  there  can  be  no  doubt  but  that  investigations 
instituted  in  this  direction  would  be  attended  by  the  development  of 
many  important  facts. 

Therapeutical  Considerations. 

The  practical  value  to  be  attached  to  the  various  particulars  related 
in  the  preceding  pages  on  the  pathology  of  the  blood,  is  so  obvious 
that  it  needs  not  to  be  illustrated  at  any  great  length. 

The  knowledge  of  the  particular  element  of  the  blood  which  in  any 
state  of  the  system  or  disease  may  be  affected,  inasmuch  as  it  discloses 
the  chief  cause  of  such  condition  or  malady,  furnishes  the  practitioner 
with  an  unerring  principle  upon  which  the  nature  and  the  extent  of 
the  treatment  adopted  should  be  founded.     Hitherto,  the  chief  guides 


158  ORGANIZED     FLUIDS. 

in  practice  have  been  based  upon  experience  and  clinical  observation; 
both,  doubtless,  of  high  importance;  but  still  not  in  many  cases 
sufficient  to  detect  the  cause  of  a  malady,  and  therefore  not  in  them- 
selves equal  to  the  determination  of  the  exact  line  of  treatment  to  be 
pursued,  or  of  the  extent  to  which  that  line  should  be  followed. 

We  are  now  not  merely  acquainted  with  the  bare  fact,  derived 
from  experience,  that  in  anaemic  conditions  of  the  system  the  different 
preparations  of  iron  are  useful,  but  we  have  dived  deeper  into  the 
mysteries  of  organization,  and  we  now  know  the  reason  why  iron  is 
necessarily  so  beneficial  in  the  disorders  to  which  such  a  condition 
of  the  system  gives  rise. 

The  precise  objects  to  be  held  in  view,  in  the  employment  of  every 
remedial  appliance  in  the  treatment  of  inflammatory  affections  and 
fevers,  we  are  now  acquainted  with ;  and  by  our  present  knowledge  we 
can  judge  of  the  propriety  and  extent  of  usefulness  of  the  various 
plans  of  treatment  which  in  times  past  have  been  had  recourse  to,  or 
which  still  continue  to  be  applied;  and  we  can  detect  the  reason  why 
one  particular  mode  of  treatment  should  have  been  more  successful 
than  another. 

Becquerel  and  Rodier's  Pathological  Researches  on  the  Blood. 

MM.  Becquerel  and  Rodier*  have  traversed  the  same  ground  as 
MM.  Andral  and  Gavarret  in  reference  to  the  blood,  which  they  have 
examined  both  in  health  and  disease. 

These  authors  confirm  many  of  the  more  important  results  obtained 
by  antecedent  observers,  but  question  the  accuracy  of  some  of  those 
results,  and  add  new  facts  in  relation  to  the  normal  and  abnormal 
composition  of  the  blood. 

The  results  which  confirm  those  which  had  been  previously  obtained 
are  the  following: 

1.  The  augmentation  of  the  fibrin  in  inflammations,  the  establish- 
ment of  which  fact  is  especially  due  to  MM.  Andral  and  Gavarret. 

2.  The  diminution  of  the  globules  in  chlorosis,  in  the  condition 
denominated  the  anaemic,  and  under  the  influence  of  fasting;  a  fact 
stated  by  M.  Lecanu,  and  confirmed  by  MM.  Andral  and  Gavarret. 

3.  The  diminution  of  the  globules  from  hemorrhages  and  anterior 
bleedings ;  a  result  which,  signalized  for  the  first  time  by  MM.  Prevost 

*  Gazette  Medicate  de  Paris,  1844.  "Recherches  sur  la  Composition  du  Sang 
dans  l'etat  de  Sante  et  dans  l'etat  de  Maladie." 


THE     BLOOD.  159 

and  Dumas,  has  been  confirmed  in  the  numerous  analyses  of  MM. 
Andral  and  Gavarret. 

4.  The  little  influence  of  bleedings  upon  the  scale  of  the  fibrin. 

5.  The  diminution  of  the  albumen  in  the  malady  of  Bright,  as 
indicated  by  Gregory,  Rostock,  Christison,  Andral  and  Gavarret. 

Of  the  results  which  differ  from,  and  perhaps  invalidate  those  of 
antecedent  observers,  the  principal  are — 

1.  That  the  scale  TVVo>  given  as  representing  the  mean  of  the 
globules  in  a  state  of  health,  is  too  low,  and  is  not  the  same  in  man 
and  in  woman. 

2.  That  the  scale  representing  the  fibrin  as  T/fj  is  too  high. 

3.  That  there  is  not  alone  in  plethora  an  augmentation  of  the 
globules,  as  signalized  by  M.  Lecanu,  and  as  has  been  admitted  by 
MM.  Andral  and  Gavarret. 

4.  That  the  scale  of  the  globules  is  not  preserved  in  its  normal 
proportion  in  the  majority  of  acute  affections. 

5.  That  the  depression  in  the  scale  of  the  fibrin  in  severe  fevers 
is  but  little  constant. 

The  more  important  of  the  new  results  are  the  following: 

1.  That  the  scale  141  expresses  the  mean  number  of  the  globules 
in  man  in  a  state  of  health,  and  that  of  127  represents  the  average  in 
woman. 

2.  That  the  ordinary  scale  of  the  fibrin  is  2*2,  and  the  mean  3. 

3.  That  in  plethora  there  is  an  augmentation  of  the  quantity  of 
the  mass  of  the  blood. 

4.  That  the  influence  of  disease  upon  the  composition  of  the 
blood  is  to  occasion  from  the  commencement  a  diminution  in  the 
proportion  of  the  globules,  and  this  diminution  continuing  during  the 
progress  of  the  malady,  ends  in  the  production  of  the  anaemic  condition 
of  the  system. 

5.  That  there  is  an  absolute  excess  of  fibrin  in  many  cases  of 
chlorosis  and  of  pregnancy,  and  that  its  diminution  is  far  less  constant 
than  has  been  considered  in  fevers. 

6.  That  the  albumen  of  the  blood  diminishes  under  the  influence 
of  illness;  that  it  is  more  considerable  in  inflammations;  and  further, 
that  the  diminution  is  in  direct  relation  with  the  augmented  amount 
of  fibrin,  which  it  may  be  presumed  is  formed  at  the  expense  of  the 
albumen ;  that  there  is  not  only  a  very  great  diminution  of  albumen 
in  the  malady  of  Bright,  but  also  in  certain  affections  of  the  heart, 
accompanied  by  dropsy,  and  in  certain  severe  forms  of  puerperal  fever. 


160  ORGANIZED     FLUIDS. 

7.  That  the  amount  of  cholesterine  and  of  acid  fats  increases  as 
we  advance  in  age ;  but  that  this  increase  is  not  felt  until  from  the 
fortieth  to  the  fiftieth  year ;  that  it  is  also  found  in  augmented  quantities 
in  the  blood  in  constipated  states  of  the  system,  and  in  jaundice,  with 
retention  of  the  bile  and  decoloration  of  the  fasces.* 

The  Blood  in  the  Menstrual  Fluid. 

The  menstrual  fluid  contains  all  the  elements  of  the  blood,  especially 
the  red  and  white  corpuscles,  and  it  is  therefore  in  the  same  manner 
as  the  blood  itself  susceptible  of  coagulation.  In  addition  to  the  con- 
stituents of  the  blood,  we  find  the  uterine  discharge  to  be  composed 
of  vaginal  mucus,  mixed  up  with  numerous  epithelial  scales,  which  it 
has  acquired  in  its  passage  along  the  vagina. 

Unlike,  however,  in  one  respect  the  blood  itself,  which  in  a  state  of 
health  is  alkaline,  the  menstrual  fluid  is  acid,  its  acidity  arising  from 
its  admixture  with  the  vaginal  secretion. 

Transfusion  of  the  Blood. 

It  has  been  stated,  and  the  statement  is  most  probably  correct,  that 
between  the  size  of  the  blood  corpuscles  and  that  of  the  capillaries 
of  the  same  animal,  an  exact  relation  exists,  and  it  is  by  reference 
to  this  fact  that  the  fatal  effects  which  have  so  often  ensued,  from  the 
transfusion  of  the  blood  of  one  animal  into  the  vessels  of  another,  have 
been  apparently  so  satisfactorily  explained.  The  little  vessels,  it 
has  been  said,  are  too  small  to  admit  the  larger  globules  of  the  new 
blood;  a  mechanical  impediment  is  thus  offered  to  the  circulation  of 
the  blood  in  the  capillaries,  which  stagnates  in  them,  giving  rise  to 
constitutional  disturbance,  and  ultimately  to  death.  This  explanation, 
plausible  as  it  appears,  has  been  shown  by  recent  experiments  to  be 
erroneous,  and  that  the  true  cause  of  the  fatality  which  has  so  often 
attended  the  operation  of  transfusion,  depends  upon  the  difference 
which  exists  in  the  qualities  of  the  fibrin  in  the  blood  of  two  different 
animals,  or  even  of  two  distinct  individuals ;  this  is  shown  by  the 
fact  that  the  transfusion  of  blood  deprived  of  its  fibrin  is  never  followed 
by  the  serious  results  to  which  reference  has  been  made.  Notwith- 
standing this  fact,  it  is  yet  very  evident  that  if  the  blood  of  an  animal, 
the  corpuscles  of  which  are  much  larger  than  the  human  blood  disc, 

*  The  above  remarks  are  abbreviated  from  an  abstract  of  MM.  Becquerel  and 
Rodier's  work  on  the  blood,  by  MM.  Millor  and  Reiset,  contained  in  the  "  Annuaim 
de  Chimie,"  for  1846. 


THE     BLOOD.  101 

and  at  the  same  time  are  of  a  different  form  and  structure — such  as, 
for  instance,  those  of  some  birds — be  introduced  into  the  vessels  of 
man,  a  very  serious  and  probably  fatal  mechanical  impediment  would 
be  presented  to  their  circulation  through  the  capillaries.  Blood  cor- 
puscles' of  a  circular  form,  and  but  little  larger  than  those  of  man, 
might  indeed  make  their  way  through  the  vessels  in  consequence  of 
the  plastic  nature  of  the  globuline  which  composes  them. 

The  new  globules  thrown  into  the  system  by  the  operation  of 
transfusion,  although  they  would  circulate  for  a  time  with  the  other 
blood  globules,  would  doubtless  all  become  destroyed  and  removed  in 
the  course  of  a  few  days,  and  this  especially  if  the  blood  corpuscles 
were  different  from  those  of  the  animal  upon  which  the  transfusion 
had  been  practised. 

The  Blood  in  an  Ecchymosis. 

When  a  part  is  bruised  to  such  an  extent  as  to  occasion  the  rup- 
ture of  the  minute  capillaries  and  vessels  contained  in  it,  blood  is 
effused,  constituting  an  ecchymosis.  The  same  effect  sometimes  takes 
place,  not  as  the  result  of  the  application  of  external  violence,  but 
from  disease,  the  solid  tissues,  and  that  of  the  vessels  especially,  giving 
way  through  debility,  and  permitting  the  escape  of  their  contents,  as 
occurs  in  malignant  and  putrid  fevers,  in  Purpura  Hemorrhagica, 
in  scurvy,  and  in  bed-sores. 

If  a  portion  of  the  effused  blood  be  removed  from  the  bruise,  and 
examined  microscopically,  the  globules  will  be  observed  to  be  wrinkled 
and  irregular  in  form ;  corresponding  with  and  depending  upon  internal 
changes  in  the  condition  of  the  blood  effused,  and  which  are  indicative 
of  the  occurrence  of  decomposition,  certain  external  appearances 
will  be  noticed ;  the  skin  will  appear  mottled,  different  hues  of  black, 
green,  and  yellow  being  intermixed,  and  varying  in  intensity  until 
the  period  of  their  total  disappearance. 

The  phenomena  of  decomposition  precede  the  disappearance  of 
the  red  corpuscles  which  are  removed  from  the  seat  of  injury,  and 
are  returned  to  the  circulation  in  a  state  of  solution.  Now,  were  the 
opinion  true  that  the  blood  corpuscles  are  applied  directly  to  the  for- 
mation of  new  tissue,  a  very  different  result  to  the  decomposition  and 
solution  of  the  globules,  to  which  we  have  referred,  would  be  antici- 
pated, and  we  should  expect  to  find  that  the  extravasated  blood  had  given 
rise  to  an  adventitious  and  organized  product,  an  event  to  which 
ecchvmoses  never  lead. 

11 


162  ORGANIZED     FLUIDS. 

The  Effects  of  certain  remedial  Agents  upon  the  Constitution  and 
Form  of  the  Blood  Corpuscle. 

We  have  seen,  in  the  remarks  on  the  effects  of  reagents,  that  many 
solutions  and  substances  applied  to  the  corpuscles,  after  their  abstrac- 
tion from  the  system,  modify  their  form,  appearance,  and  properties. 

Thus  we  have  seen  that  in  water,  as  in  any  other  analogous  liquids 
of  less  specific  gravity  than  the  serum  of  the  blood,  that  the  corpuscles 
lose  their  normal  form,  and  become  circular,  their  colouring  matter 
passing  at  the  same  time  into  the  fluid. 

We  have  likewise. observed  that  in  liquids  of  an  opposite  character, 
and  the  density  of  which  equals  or  exceeds  that  of  the  blood,  their 
form  is  preserved,  and  even  rendered  flatter  than  ordinary:  thus, 
their  shape  is  well  maintained  or  but  slightly  affected  in  the  white  of 
egg,  urine,  the  saliva,  concentrated  solutions  of  sugar,  of  the  chlorides 
of  sodium,  and  of  ammonium,  and  the  carbonates  of  potassa  and 
ammonia. 

The  blood  corpuscles  likewise  preserve  their  form  in  the  solutions 
of  other  substances,  the  density  of  which  would  not  appear  to  be  very 
great,  but  which  are  possessed  of  very  strong  and  decided  properties : 
thus,  they  maintain  their  shape  well  in  a  solution  of  iodine,  and  become 
but  slightly  contracted  in  that  of  chloride  of  sodium;  while,  according 
to  Henle,  the  primitive  flattened  form  of  corpuscles,  swollen  by  the 
imbibition  of  water,  may  be  restored  to  them  by  the  application  of 
the  concentrated  saline  solutions. 

Nitric  acid  produces  an  irregular  contraction  of  the  corpuscles.  It 
has  been  remarked  in  like  manner  that  a  host  of  substances  affect 
the  colour  of  the  corpuscles. 

But  it  is  not  alone  the  form  and  colour  of  the  blood  corpuscles 
which  are  affected  by  the  contact  of  reagents;  their  properties  also 
are  modified  by  them. 

Thus,  the  corpuscles  to  which  iodine  has  been  added  are  so  hardened 
by  it,  that  they  experience  little  or  no  change  of  form  on  the  addition 
of  water. 

The  same  is  the  case,  according  to  Henle,  after  treatment  by  nitric 
acid. 

The  acetic,  and  one  or  two  other  acids,  it  is  known,  dissolve  the 
corpuscles  of  the  mammalia  without  residue,  but  leave  almost  unaf- 
fected the  granular  nucleus  contained  in  the  red  blood  corpuscles  of 
oviparous  vertebrata. 


THE     BLOOD.  163 

The  above  are  some  of  the  more  striking  effects  produced  in  the 
form,  colour,  and  constitution  of  the  blood  corpuscles  out  of  the  sys- 
tem, on  their  treatment  by  reagents. 

Now,  there  is  evidence  to  show  that  blood  corpuscles,  while  they 
are  circulating  in  the  body,  are  likewise  affected,  although  to  an 
extent  less  considerable,  and  therefore  less  appreciable,  by  substances 
and  solutions  introduced  into  the  system  through  the  medium  of  the 
lungs  or  of  the  stomach. 

Thus,  we  know  that  the  blood  changes  its  colour  in  the  lungs  and 
during  its  circulation  through  the  capillaries,  and  that  these  changes 
are  dependent  upon  the  relative  amount  of  oxygen  and  of  carbon 
contained  in  the  corpuscles. 

Again,  it  has  been  asserted  by  Schultz,  as  already  mentioned,  that, 
accompanying  these  alterations  of  colour,  there  are  also  changes  of 
form,  the  corpuscles  becoming  more  or  less  circular  in  carbonic  acid 
and  hydrogen  gases,  and  flat  in  oxygen  gas.  This  assertion  I  have 
myself  failed  to  verify. 

It  cannot  be  doubted,  however,  but  that  the  form  of  the  red  blood 
corpuscle  must  vary  according  to  the  variations  of  density  experienced 
by  the  liquor  sanguinis,  and  further  but  little  hesitation  can  be  felt 
in  admitting  that  this  alteration  of  density  does  really  attend  upon 
particular  conditions  of  the  system ;  thus,  in  inflammatory  affections, 
the  liquor  sanguinis  is  assuredly  more  dense  than  it  is  in  states  in 
which  an  opposite  condition  of  the  blood  exists,  that  in  which  the 
watery  element  abounds. 

After  very  copious  imbibition  of  water,  also,  it  can  scarcely  be 
doubted  but  that  the  density  of  the  blood  is  lessened,  and  that  the  red 
corpuscles  are  modified  in  shape  in  consequence. 

Thus  much  for  colour  and  form ;  let  us  see  if  we  are  acquainted 
with  any  fact  capable  of  proving  that  the  constitution  of  red  blood 
corpuscles  is  also  influenced  by  the  introduction  into  the  stomach  of 
remedial  agents. 

Schultz  relates  the  fact  that  the  corpuscles  of  the  frog,  in  the 
mouth  of  which  during  life  iodine  had  been  placed,  resisted  for  a 
longer  time  the  action  of  water.*  The  truth  of  this  most  interesting 
and  important  observation  I  have  myself  verified. 

The  blood  corpuscles  of  a  frog,  which  were  subjected  to  the  vapour 
of  iodine,  underwent  no  appreciabe  change  of  form  in  water  for 
nearly  an  hour  during  which  they  were  observed,  a  time  more  than 
*  Das  System  der  Circulation.     Stuttgard,  1836,  p.  19. 


164  ORGANIZED     FLUIDS. 

sufficient  to  ensure  the  complete  change  of  shape  and  subsequent 
disintegration  of  the  blood  discs  of  a  frog  not  similarly  treated. 

It  may  be  observed  that  in  the  case  related,  starch  failed  to  detect 
the  presence  of  iodine,  although  this  was  set  free  by  previously  dis- 
solving the  corpuscles  by  means  of  acetic  acid. 

After  the  relation  of  the  above  facts,  it  is  evident  that  remedial 
agents  do  affect  in  several  important  particulars  the  blood  corpuscles 
of  the  living  animal,  and  it  is  further  probable  that  a  considerable 
proportion  of  their  remedial  influence  is  dependent  upon  the  nature 
and  extent  of  their  power  in  modifying  the  red  blood  disc. 

The  Importance   of  a  Microscopic  Examination  of  the  Blood  in 

Criminal  Cases. 

In  criminal  cases  it  is  sometimes  a  matter  of  the  highest  importance 
to  the  furtherance  of  the  ends  of  justice,  that  the  nature  of  certain 
stains,  observed  on  the  clothes  of  an  accused  person,  should  be  clearly 
ascertained. 

The  fact  usually  to  be  determined  is,  whether  the  stains  in  question 
are  those  of  blood  or  not.  Now,  in  the  decision  of  this  important 
matter,  the  microscope  comes  to  our  aid  in  a  manner  the  most  deci- 
sive and  convincing. 

If  the  stain  be  a  blood  stain,  and  if  its  examination  be  properly 
conducted,  the  microscope  will  lead  to  the  detection  in  it  of  the  blood 
corpuscles  themselves,  both  white  and  red. 

The  inquiry  having  been  proceeded  with  thus  far,  and  the  stain 
having  been  proved  to  be  one  formed  by  blood,  it  still  remains  for 
decision,  whether  the  blood  thus  detected  is  human  or  not. 

In  the  solution  of  this  difficulty  the  microscope  likewise  affords 
considerable  assistance,  and  this  of  a  kind  which  can  be  obtained  in 
no  other  way.  Although  by  this  instrument  we  are  not  able  to  assert 
positively  from  an  examination  of  the  blood  stain  itself,  free  from 
admixture  with  any  other  organic  material,  that  the  blood  is  really 
human,  we  yet  shall  have  it  in  our  power  very  frequently  to  declare 
the  converse  fact,  viz :  that  a  certain  blood  stain  is  constituted  of 
blood  which  is  not  human,  a  particular  on  the  knowledge  of  which 
the  life  of  an  accused  individual  might  depend. 

Thus,  if  we  find  that  the  blood  globules  are  of  a  circular  form,  and 
destitute  of  nuclei,  we  may  safely  conclude  that  they  belong  to 
an  animal  of  the  class  Mammalia,  although,  at  the  same  time,  we  in 
all  probability  should  not  be  able  to  pronounce  upon  the  name  of  the 


THE     BLOOD.  1G5 

mammal  itself;  if,  on  the  contrary,  the  blood  corpuscles  are  elliptical, 
and  provided  with  a  granular  nucleus,  we  may  be  equally  certain 
that  they  do  not  appertain  to  that  class,  but  either  to  the  division  of 
birds,  fishes,  or  reptiles.* 

By  the  size  also  as  well  as  the  form  of  the  corpuscles,  some  idea  of 
the  animal  from  which  the  blood  was  derived  might  be  formed ;  and 
if  we  cannot  pronounce  with  certainty  upon  this,  we  shall  at  all 
events,  and  at  all  times,  be  able  to  go  the  length  of  affording  negative 
evidence,  and  of  asserting  that  the  corpuscles  do  not  represent  the 
blood  of  certain  animals  which  might  be  named,  and  a  knowledge  of 
which  fact  might  prove  of  extreme  importance. 

To  show  the  valuable  nature  of  the  evidence  which  it  is  in  the 
power  of  a  medical  man  who  makes  a  right  use  of  the  microscope 
frequently  to  afford,  in  criminal  inquiries,  we  will  suppose  the  follow- 
ing case: 

A  person  is  apprehended  on  the  suspicion  of  having  been  concerned 
in  a  murder.  On  his  clothes  are  observed  certain  stains;  upon  these 
he  is  questioned;  he  admits  that  they  are  blood  stains,  and  states  that 
he  had  been  engaged  in  killing  a  fowl,  and  that  in  this  way  his  clothes 
had  acquired  the  marks.  The  stains  are  now  submitted  to  micro- 
scopic examination ;  the  blood  of  which  they  are  constituted  is  found 
to  belong  to  an  animal  of  the  class  Mammalia,  and  not  to  that  of 
Aves;  discredit  is  thus  thrown  upon  the  party  suspected,  fresh 
inquiries  are  instituted,  fresh  discoveries  made,  and  the  end  of  all  is 
the  conviction  of  the  accused  of  the  crime  imputed. 

But  a  third  question  presents  itself,  to  which  it  is  very  necessary 
that  a  satisfactory  reply  should  be  made,  viz :  did  the  blood,  of  which 
the  stain  is  constituted,  flow  from  a  living  or  dead  body?  This  query 
we  will  proceed  to  answer. 

If  a  vessel  be  opened  during  life,  or  even  a  few  minutes  after  death, 
the  blood  which  issues  from  it  in  a  fluid  state  will  quickly  become 
solidified  from  the  coagulation  of  the  fibrin. 

But  if.  on  the  other  hand,  a  vessel  be  opened  some  hours  after 
death,  the  fluid  blood  which  escapes  will  not  solidify  because  it  con- 
tains no  fibrin,  this  element  of  the  blood  having  already  become 
coagulated  in  the  vessels  of  the  body  in  which  it  still  remains. 

Now,  this  act  of  the  solidification  of  the  fibrin  is  deemed  by  many 

*  The  only  animals  of  the  class  Mammalia  which  have  blood  corpuscles  of  an 
elliptical  form,  are  those  of  the  order  Camelidcc ;  they  are,  however,  very  small,  and 
destitute  of  nuclei. 


166  ORGANIZED      FLUIDS. 

to  be  a  vital  act,  and  to  be  the  last  manifestation  of  life  on  the  part 
of  the  blood. 

It  would  appear,  however,  that  the  coagulation  of  the  blood  should 
not  be  regarded  as  a  vital  act,  seeing  that  blood  which  has  been  kept 
fluid  for  some  time  by  admixture  with  saline  salts  will  coagulate  when 
largely  diluted  with  water,  and  also,  that  blood  which  has  been  frozen 
previous  to  coagulation  will  undergo  the  process  of  solidification  after 
it  has  been  rendered  fluid  again  by  thawing.* 

Presuming,  then,  that  the  coagulation  of  the  blood  is  not  an  act  of 
vitality,  the  inference  to  be  deduced  from  the  presence  of  coagulated 
fibrin  in  blood  stains,  in  which  the  corpuscles  may  be  detected,  is 
scarcely  weakened  thereby,  since  the  finding  of  such  fibrin  in  such  a 
situation,  and  in  connexion  with  the  blood  corpuscles,  scarcely  admits 
of  a  rational  and  probable  explanation  of  its  occurrence  being  given 
apart  from  the  idea  that  the  blood  had  issued  from  a  body  either  liv- 
ing or  but  just  dead,  and  in  which  coagulation  of  the  fibrin  in  the 
vessels  had  not  occurred. 

The  blood  stains,  therefore,  which  contain  coagulated  fibrin  in 
them,  it  is  but  little  doubtful,  must  have  proceeded  either  from  a  liv- 
ing individual,  or  from  one  but  just  dead ;  while,  on  the  contrary,  it 
is  as  little  to  be  doubted,  but  that  those  stains  which  do  not  contain 
solidified  fibrin,  must  have  emanated  from  a  body  dead  some  hours, 
or  from  blood  which  had  already  been  deprived  of  its  fibrin. 

From  the  disposition  and  form  also  of  the  blood  spots,  some  idea 
can  be  formed  as  to  whether  the  blood  had  sprit  out  of  a  living  body 
or  not. 

A  few  observations  may  now  be  made,  first,  on  the  length  of  time 
after  the  formation  of  blood  stains  at  which  the  corpuscles  can  be 
detected ;  and  second,  on  the  best  mode  of  proceeding  in  the  exam- 
ination of  those  stains. 

From  observations  which  I  have  made,  it  would  not  appear  that  it 
is  necessary  that  the  blood  stain  should  be  recent.  I  am  inclined  to 
think  that  the  period  scarcely  admits  of  limitation. 

Thus  in  blood  stains  six  months  old,  I  have  observed  the  corpus- 
cles presenting  very  nearly  the  form  and  appearance  proper  to  them 
when  recently  effused,  and  previous  to  their  becoming  dried  up. 

In  the  blood  of  the  frog,  six  months  after  its  abstraction  from  the 

*  Dr.  Polli  has  related  a  case  in  which  the  complete  coagulation  of  the  blood  did 
not  take  place  until  fifteen  days  after  its  abstraction. — Gazzetta  Medica  di  Milando, 
1844.    ■ 


THE     BLOOD.  167 

animal,  I  have  observed  the  corpuscles,  both  red  and  white,  and  in 
the  former,  the  characteristic  granular  nuclei  with  so  much  clearness, 
that  it  would  have  been  an  easy  matter  to  have  studied  upon  them 
the  development  of  blood  corpuscles. 

The  observance  of  one  precaution,  at  least,  is  necessary  for  the 
successful  exhibition  of  the  microscopic  characters  of  blood  stains. 

Thus,  water  should  never  be  applied  to  them,  nor  indeed  any  other 
fluid,  the  density  of  which  is  less  than  that  of  the  serum  of  the  blood, 
for  all  such  liquids  will  occasion  the  discharge  of  the  colouring  mat- 
ter of  the  blood  corpuscles  and  an  alteration  of  their  form ;  thus  the 
circular  but  flattened  corpuscles  of  the  Mammalia  will  assume  a  glob- 
ular shape,  as  will  also  the  elliptical  blood  discs  of  birds,  fishes,  and 
reptiles ;  one  of  the  greatest  points  of  difference  between  the  blood 
corpuscles  of  the  former  and  latter  classes  being  thereby  effaced. 

Blood  stains,  therefore,  should  be  moistened,  previous  to  examina- 
tion, with  some  fluid,  the  density  of  which  nearly  equals  that  of  the 
liquor  sanguinis;  and  I  have  found  the  albumen  of  the  egg  to  pre- 
serve the  form  of  the  corpuscles  excellently  well. 

Failing,  however,  in  detecting  the  blood  corpuscles,  a  result  scarcely 
to  be  anticipated,  assistance  may  be  derived  from  a  toxicological 
examination  of  the  blood. 

The  only  tests  peculiar  to  the  blood  are  those  which  have  relation 
to  the  haematine.  This  principle  it  would,  however,  be  difficult  to 
obtain  from  blood  stains  in  sufficient  quantity  for  the  purposes  of 
copious  chemical  analysis. 

Nevertheless,  corroborative  evidence  of  the  suspected  character  of 
a  stain  might  be  obtained  by  its  general  chemical  analysis,  and  which 
should  be  treated  as  follows: 

The  stain  should  first  be  moistened  with  cold  distilled  water;  as 
much  of  the  matter  of  it  should  then  be  removed  as  possible,  and 
placed  in  a  test  tube  with  an  additional  quantity  of  water.  This 
being  agitated,  the  colouring  material,  if  the  stain  be  a  blood  stain, 
will  be  dissolved  by  the  water,  imparting  to  it  a  pinkish  colour,  while, 
provided  the  blood  flowed  from  the  body  during  life,  or  at  all  events 
within  a  few  minutes  of  decease,  suspended  in  the  liquid,  will  be  seen 
shreds  of  fibrin. 

This  solution,  when  heated  to  near  the  boiling  point,  will  become 
turbid,  and  deposit  flakes  of  albumen. 

The  same  thing  will  occur  when  it  is  treated  with  nitrate  of  silver 
or  bichloride  of  mercury. 


168  ORGANIZED     FLUIDS. 

The  addition  of  a  strong  acid  or  alkali  turns  the  colouring  matter 
of  a  brown  tint. 

These  results,  however,  are  common  to  other  mixtures  of  animal 
substances  in  combination  with  colouring  matter  besides  the  blood, 
and  no  one  of  them  is  perfectly  characteristic. 

It  would  therefore  appear  that  the  microscope  is  capable  of  reveal- 
ing evidence  much  more  satisfactory  in  reference  to  the  nature  of 
blood  stains,  than  that  which  it  is  possible  to  derive  from  chemical 
examination. 

Finally,  it  may  be  observed,  that  during  the  examination  of  blood 
stains,  other  substances  may  be  detected  in  connexion  with  them,  the 
presence  of  which  would  reveal  not  merely  their  nature,  but  also  the 
seat  from  which  the  blood  forming  them  had  flowed ;  thus,  some  of  the 
various  forms  of  epithelial  cells  and  of  hairs,  may  occasionally  be 
encountered  in  them. 

We  now  bring  to  a  conclusion  this  long  article  upon  the  grand  for- 
mative fluid  of  the  system,  the  blood,  and  pass  to  the  consideration  of 
other  fluids  of  the  economy,  viz :  pus  and  mucus. 


THE      BLOOD.  109 


PREPARATION. 


[Fresh  blood  may  be  examined  by  placing  a  very  small  quantity  on  a 
plain  glass  slide,  thinning  it  with  a  little  serum,  and  quickly  covering  it  with 
a  piece  of  thin  glass.  The  object  is  then  ready  for  examination,  and  will 
require  a  power  of  600  to  650  diameters,  to  well  define  its  corpuscles.  The 
different  reagents  may  then  be  introduced  by  means  of  a  pipette :  the  most 
striking  in  their  effects,  are  water,  acetic  acid,  nitric  acid,  and  alcohol. 

Perhaps  the  most  marvellous  sight  that  the  microscopist  can  behold,  is 
that  of  the  circulation  of  the  blood.  For  this  purpose,  the  frog  is  usually 
selected,  and  instructions  have  already  been  given  for  preparing  the  tongue, 
so  as  to  show  this  phenomenon. 

There  are  other  portions  of  the  frog  in  which  the  circulation  may  be 
readily  seen  ;  one  of  these  is  the  transparent  part  of  the  web  of  the  hind 
feet.  In  this  manipulation,  the  body  of  the  frog  is  to  be  secured  to  the 
frog-plate,  by  means  of  a  narrow  bandage  or  piece  of  tape.  Those  who 
do  not  possess  a  frog-plate,  may  readily  make  one  by  taking  a  piece  of  thin 
board  about  six  inches  long,  and  three  inches  wide;  in  this,  a  hole  an  inch 
square  is  to  be  cut  near  one  end.  The  frog,  secured  in  the  bag,  is  tied  to 
the  solid  part  of  the  thin  board,  in  such  a  manner  that  the  web  of  the  foot 
may  be  brought  over  the  hole.  The  foot  is  then  stretched  out  to  the  utmost, 
and  fastened  in  this  condition  by  means  of  strings  tied  to  the  toes,  and 
secured  to  small  pegs,  or  tacks,  driven  in  at  the  margin  of  the  board. 
Another  method  of  securing  the  web  in  a  state  of  tension,  is  by  means  of 
pins  run  through  the  toes,  and  fastened  to  the  board.  The  plate,  when  ready, 
is  placed  upon  the  stage  of  the  microscope,  and  the  web  may  be  examined 
by  means  of  a  power  from  50  to  100  diameters.  Any  very  transparent 
part  may  be  examined  with  a  much  higher  power,  even  to  670  diameters. 
The  web  should  be  kept  moist  with  clear  water. 

Mr.  Quekett  observes,  (page  339)  "  A  frog  so  mounted,  is  capable  of  exhibit- 
ing many  of  the  effects  of  inflammation ;  if,  for  instance,  a  spot  in  the  web 
be  touched  with  the  point  of  a  needle,  or  a  small  drop  of  alcohol,  or  other 
stimulating  fluid  be  placed  upon  it,  the  circulation  will  stop  in  that  part  for 
a  longer  or  shorter  period,  according  to  the  amount  of  injury  inflicted  ;  the 
vessels  in  the  neighbourhood  will  soon  become  turgid,  and  even  sometimes  be 
entirely  clogged  up  with  blood;  if  no  further  stimulus  be  applied,  they  will 
be  seen  to  rid  themselves  of  their  contents  as  easily  as  they  became  full,  and 
after  a  time,  the  circulation  will  be  restored  in  every  part.  For  those  who 
are  unacquainted  with  the  parts  which  may  be  observed  with  the  micro- 
scope, in  the  foot  of  the  frog,  it  may  be  as  well  here  to  state,  that  the 
majority  of  vessels  in  which  the  blood  is  seen  to  circulate,  are  veins  and 
capillaries;  the  former  may  be  known  by  their  large  size,  and  by  the  blood 
moving  in  them  from  the  free  edge  of  the  web  towards  the  leg ;  also,  by  their 


170  ORGANIZED      FLUIDS. 

increase  in  diameter  in  the  direction  of  the  current ;  the  latter  are  much 
smaller  than  the  veins,  and  their  size  is  nearly  uniform ;  the  blood  also  cir- 
culates in  them  more  quickly.  The  arteries  are  known  by  their  small  size, 
and  by  the  great  rapidity  with  which  the  blood  flows  in  them ;  they  are  far 
less  numerous  than  either  of  the  other  vessels,  and,  generally  speaking,  only 
one  can  be  recognised  in  the  field  of  view  at  a  time ;  in  consequence  of 
their  being  imbedded  deeper  in  the  tissues  of  the  web  than  the  other  ves- 
sels, the  circulation  cannot  be  so  well  defined  as  in  the  latter.  The  black 
spots  of  peculiar  shapes  that  occur  in  all  parts  of  the  web,  are  cells  of  pig- 
ment, and  the  delicate  hexagonal  nucleated  layer,  which,  with  a  power  of 
one  hundred  diameters,  can  be  seen  investing  the  upper  surface  of  the  web, 
is  tesselated  epithelium." 

If  the  lung  or  mesentery  of  the  frog  be  desired  for  exhibition,  and  they 
will  both  be  found  to  display  the  most  beautiful  sight  that  can  be  conceived, 
the  following  method  must  be  adopted :  The  frog  must  be  dipped  in  water, 
at  about  120°  temperature;  this  heat  will  destroy  muscular  action,  but  will 
not  suspend  the  circulation.  The  animal  is  then  to  be  opened,  and  the  lungs 
full  of  air  will  protrude ;  one  of  these  is  bent  over  on  a  plain  glass  slide, 
and  may  be  then  viewed  with  a  low  power.  The  mesentery  may  be  dis- 
sected out,  and  viewed  in  the  same  way. 

When  the  tad-poles  of  the  water-newt  and  frog  can  be  found,  and  they 
are  abundant  in  the  latter  summer  and  early  fall  months,  the  tails  of  these 
little  creatures  afford  beautiful  views  of  the  circulation.  No  further  prepa- 
ration is  necessary  than  enveloping  their  bodies  in  bibulous  paper,  leaving 
their  tails  to  project ;  they  are  then  placed  on  the  stage  of  the  microscope 
in  a  watch-glass  or  live-box,  and  without  any  pain  or  injury  to  the  animal, 
may  be  observed  for  hours,  by  keeping  the  bibulous  paper  moistened  with 
water. 

PEESEEYATION. 

The  blood  corpuscles  may  be  readily  preserved  for  future  examination, 
by  placing  a  small  quantity  of  fresh  blood  on  a  plain  glass  slide,  and  rapidly 
passing  the  slide  backwards  and  forwards,  so  as  to  dry  the  blood  as  soon  as 
possible.  The  corpuscles  will  then  be  found  to  be  but  little  altered  in  form  ; 
they  are  then  to  be  covered  with  a  piece  of  very  thin  glass,  which  must  be 
cemented  down  with  gold  size,  taking  care  to  paint  on  a  very  thin  layer  at 
first,  and  a  thicker  one  afterwards,  when  the  first  has  become  dry.  Blood 
corpuscles,  so  preserved,  will  keep  for  years.  They  may  also  be  preserved 
in  the  flat  cell,  with  Goadby's  A-2  solution,  or  in  a  weak  solution  of  chromic 
acid,  care  being  taken  that  the  cell  be  tightly  sealed. 

Specimens  of  the  blood  of  many  birds,  fishes,  reptiles,  and  mammalia, 
may  be  readily  procured,  and  when  preserved  in  the  manner  already 
described,  will  form  objects  of  great  interest.] 


MUCUS.  171 


ART.    III.— MUCUS. 

We  have  seen  that  the  blood  consists  of  two  parts,  the  one  fluid, 
the  liquor  sanguinis,  the  other  solid,  the  globules ;  the  same  constitu- 
tion belongs  also  to  mucus  as  well  as  to  some  other  of  the  animal 
fluids,  as,  for  example,  pus  and  milk. 

Mucous  globules  find  their  analogue  in  the  white  corpuscles  of  the 
blood,  while  the  fluid  portion  of  mucus  resembles  closely  the  fibrin  of 
the  blood,  fibrillating  or  resolving  itself  into  fibres  in  the  same  manner 
as  the  fibrin.  From  this  fact  there  can  be  no  doubt  but  that  the 
transparent  or  fluid  constituent  of  mucus  is  mainly  composed  of  fibrin. 

It  is  probable  that  the  fluid  portion  is  the  only  essential  constituent 
of  mucus,  and  that  the  globules  are  connected  with  it  merely  in  an 
indirect  and  secondary  manner,  notwithstanding  that  their  presence 
is  all  but  constant.  The  correctness  of  this  view  is  in  some  measure 
sustained  by  the  fact,  observed  first  by  M.  Donne,  that  the  mucus 
obtained  from  the  neck  of  the  uterus,  in  young  girls,  is  invariably 
free  from  corpuscles. 

It  is  with  the  solid  particles  of  the  mucus  that  we  shall  be  chiefly 
occupied,  for  they  more  properly  enter  into  the  domain  of  the  micro- 
scope; the  fluid  element  eludes  to  a  great  extent  the  power  of  this 
instrument,  and  the  detection  of  its  properties  enters  principally  into 
the  province  of  the  chemist. 

GENERAL      CHARACTERS. 

Healthy  mucus,  in  its  fluid  state,  is  a  transparent,  viscid  and  jelly- 
like substance,  which  does  not  readily  become  putrescent;  in  its  dried 
condition,  it  assumes  a  dark  appearance,  and  a  horny  and  semi- 
opaqe  texture ;  in  water  it  swells  up,  reacquiring  most  of  the  prop- 
erties which  characterized  it  when  recent.  It  sometimes  exhibits  an 
acid,  and  sometimes  an  alkaline  reaction,  according  to  the  exact 
structure  of  the  mucous  membrane  by  which  the  mucus  is  itself 
secreted. 

Mucous  membranes,  therefore,  as  might  be  inferred  from  the  con- 
cluding passage  of  the  preceding  paragraph,  do  not  all  present  a 
constitution  precisely  similar  the  one  to  the  other ;  and  on  their  differ- 
ences of  organization  a  division  of  them  into  three  classes  may  be 
instituted,  as  has  been  pointed  out  by  M.  Donne. 


172  ORGANIZED     FLUIDS. 

The  first  class  of  mucous  membranes  comprises  those  which  are 
contiguous  to  the  outlets  of  the  body,  and  which  are  to  be  regarded  • 
as  extensions  of  the  skin,  participating  in  all  its  properties:  thus,  the 
fluid  secreted  by  this  class  of  mucous  membranes  manifests,  like  that 
of  the  skin,  an  acid  reaction,  and  the  same  epithelium  which  invests 
the  latter  belongs  also  to  the  former;  in  other  respects  the  corres- 
pondence is  likewise  exhibited,  the  membranes  under  consideration 
manifest  the  same  sensibility,  the  same  freedom  from  hemorrhage, 
which  characterize  the  skin;  they  in  like  manner  ulcerate  less  readily, 
and  are  never  furnished  with  the  vibratile  cilia  which  belong  to  the 
second  class  of  mucous  membranes,  viz :  the  true.  This  first-described 
class  of  membranes  may  be  denominated  false  mucous  membranes; 
and,  as  an  example  of  it,  the  vagina  may  be  cited. 

The  membranes  which  belong  to  the  second  class  are  situated 
more  internally  than  the  last,  and  have  scarcely  any  thing  in  common 
with  those  of  the  first  class :  the  mucus  secreted  by  them  constantly 
exhibits  an  alkaline  reaction,  and  the.  epithelium  which  invests  them 
is  of  a  totally  different  structure,  the  cells  which  constitute  it  being 
cuneiform,  and  in  some  situations  provided  with  numerous  vibratile 
cilia:  the  general  properties  of  this  class  of  membranes  are  also 
opposed  to  those  of  the  previous  division:  thus,  they  are  but  little 
sensitive  to  the  touch,  are  frequently  the  seat  of  hemorrhages,  and 
ulcerate  with  much  facility.  The  membranes  of  this  class  are  to  be 
considered  as  the  true  mucous  membranes,  and  that  which  lines  the 
trachea  and  bronchi  may  be  instanced  as  the  type  of  this  class. 

The  third  class  is  more  artificial  than  the  two  preceding  ;  the 
membranes  which  it  comprises  exhibit  in  a  greater  or  less  degree 
the  characters  of  each  of  the  divisions  already  described,  between 
which  they  are  intermediate  in  situation,  as  in  structure,  participating 
in  the  characters  of  the  false  or  true  mucous  membranes  more  or  less, 
according  to  the  preponderance  of  either  of  these  classes.  The 
membranes  of  this  division  may  be  called  mixed,  and  those  of  the 
mouth  and  nose  may  be  regarded  as  typical. 

Now,  however  useful  for  the  purposes  of  description  the  above 
classification  may  be,  it  must  still  be  remembered  that  it  is,  to  a  very 
considerable  degree,  arbitrary ;  the  membranes  which  we  have  described 
as  false  mucous  membranes  belong  rather  to  the  skin  than  to  true 
mucous  structure,  while  the  mixed  membranes  exhibit  only  the  grad- 
ual transition  from  the  external  skin  to  the  internal  true  mucous 
membrane:  thus,  strictly  speaking,  there  is  but  one  class  of  mucous 


mucus.  1 73 

membranes,  and  that  the  true.  Corresponding  with  the  differences 
which  have  been  pointed  out  as  characteristic  of  the  three  classes  of 
mucous  membranes,  there  are  others  appertaining  to  the  mucus 
secreted  by  each  of  these  orders  of  membranes,  and  which  arise  from 
their  diversity  of  structure,  and  which  serve  to  distinguish  the  mucus 
of  the  one  class  from  that  of  each  of  the  other  classes. 

1st.  The  mucus  proceeding  from  true  mucous  membranes  is  vis- 
cous and  alkaline,  containing,  imbedded  in  its  substance,  numerous 
spherical,  semi-transparent,  and  granular  corpuscles  of  about  the 
2 2V0  °f  an  mcn  m  diameter  (see  Plate  XL  fig.  1),*  having  a  some- 
what broken  outline,  as  well  as  occasionally  epithelial  cells  more  or 
less  cuneiform,  and  sometimes,  provided  with  cilia.  These  corpus- 
cles are  for  the  most  part  nucleated,  they  are  not  at  first  soluble  in 
water,  but  swell  up  in  that  fluid  to  two  or  three  times  their  former 
dimensions  (see  Plate  XI.  fig.  3),  and,  like  the  white  globules  of  the 
blood,  to  which  they  bear  the  closest  possible  resemblance,  they  con- 
tract somewhat  under  the  influence  of  acetic  acid,  and  are  soluble  in 
a  concentrated  solution  of  ammonia. 

2d.  The  mucus  secreted  by  false  mucous  membranes,  or  those  which 
are  analogous  to  the  skin,  although  more  or  less  thick,  does  not  admit 
of  being  drawn  out  into  threads,  is  acid,  and,  in  place  of  spherical 
globules,  contains  numerous  scales  of  epithelium,  which  differ  from 
true  mucous  globules  in  their  much  larger  size,  flattened  form,  and  in 
their  irregular  and  very  frequently  oval  outline:  these  scales,  like  the 
true  mucous  corpuscles,  are  nucleated,  and  the  nuclei  comport  them- 
selves with  chemical  reagents,  in  the  same  manner  as  the  globules  of 
mucus. 

Example: — the  mucus  of  the  vagina.     (See  Plate  XII.  fig.  1.) 

3d.  The  mucus  proceeding  from  the  mixed  or  transition  membranes 
is  sometimes  acid,  sometimes  alkaline,  at  others  neutral,  and  contains 
a  mixture  of  true  mucous  corpuscles  and  epithelial  scales,  the  relative 
proportion  of  each  of  which  varies  according  to  the  exact  structure 
of  the  membrane  by  which  it  is  furnished.     (See  Plate  XII.  fig.  2.) 

These  divisions  of  the  mucus  into  three  different  kinds,  although  to 
some  extent  artificial,  as  already  observed,  are  yet  not  without  their 
practical  utility. 

*  A  law  having  reference  to  size,  and  the  importance  of  which  will  be  hereaftef 
demonstrated,  may  here  he  announced.  It  is  that  the  several  structures,  especially 
the  corpuscular  ones,  entering  into  the  composition  of  the  animal  organization,  hear 
a  near  relation  of  size  the  one  to  the  other. 


174  ORGANIZED     FLUIDS. 

The  microscopical  and  chemical  characters  of  mucus  likewise  vary 
much,  not  merely  according  to  the  general  organization  of  the  mem- 
brane by  which  it  is  secreted,  but  also  in  accordance  with  the  condi- 
tion of  the  membrane  itself,  with  the  degree  of  irritation  or  inflam- 
mation to  which  it  is  subject,  and  with  the  precise  nature  of  the 
disorder  by  which  it  is  affected ;  thus,  sometimes,  the  mucus  secreted 
by  the  lining  membrane  of  the  nose  is  thin  and  watery,  the  fluid 
element  being  in  excess,  and  at  others  it  is  thick  and  opaque,  its  solid 
globular  constituents  super-abounding.  Its  colour  also  as  well  as  its 
consistence  exhibits  various  modifications  in  pathological  states, 
being  sometimes  white,  greenish  or  yellow. 

The  description  of  the  different  forms  of  epithelial  cells  alluded  to, 
and  which  are  occasionally  encountered  in  the  mucus  mixed  up  with 
true  mucous  corpuscles,  belongs  not  to  the  fluids,  and  will  be  given 
in  detail  under  the  head  of  Epithelium,  in  that  division  of  the  work 
which  is  devoted  to  the  consideration  of  the  solids  of  the  human 
body;  the  structure,  form,  size,  properties  and  nature  of  the  true 
mucous  corpuscles  may  here  be  described  with  advantage. 

MUCOUS     CORPUSCLES. 

Structure. — The  mucous  corpuscles,  which  are  colourless,  and 
mostly  of  a  circular  form,  are  each  constituted  of  a  nucleus,  an  envel- 
ope, an  intervening  fluid  substance,  and  numerous  granules,  which 
are  diffused  generally  throughout  the  entire  of  the  corpuscles,  being 
contained  within  the  cavity  of  the  nucleus,  in  the  space  between  this 
and  the  outer  envelope,  and,  lastly,  in  the  substance  of  the  envelope 
itself;  this  arrangement  imparting  a  granular  texture  to  the  entire 
corpuscle.     (See  Plate  XL) 

The  nucleus,  like  the  corpuscle  itself,  is  a  circular  body  of  about 
one-third,  or  one-fourth  its  size :  it  sometimes  occupies  a  central,  but 
very  frequently  an  eccentric  position  in  the  mucous  globule :  it  is  not 
at  all  times  visible,  although  very  generally  so,  without  the  addition 
of  reagents,  the  best  being  water  and  acetic  acid. 

The  addition  of  water  to  mucous  corpuscles  discloses,  in  the 
majority  of  them,  but  a  single  nucleus  (see  Plate  XI.  Jig.  3) ;  in  some, 
however,  two  and  even  three  or  four  nucleoli  appear,  these  resulting 
from  the  division  of  the  substance  of  the  single  primary  nucleus. 
1  The  effect  of  a  weak  solution  of  acetic  acid  is  the  same  as  that  of 
water,  except  that  an  additional  number  of  corpuscles  are  seen  after 
its  application  to  possess  the  divided  nucleus,  while  in   others  the 


mucus.  175 

single  nucleus  is  observed  to  be  oval,  and  occasionally  contracted  in 
the  centre — this  form  being  the  transition  one  from  the  single  to  the 
double  nucleus.     (See  Plate  XJ.fig.  4.) 

If  undiluted  acetic  acid  be  used,  then  all  the  corpuscles  will  present 
a  compound  nucleus,  consisting  of  two,  three,  four,  or  five  nucleoli, 
the  usual  number  being  two  or  three;  the  investing  membrane  at  the 
same  time  under  its  influence  loses  its  granular  aspect,  and  appears 
transparent  and  smooth.     (See  Plate  XI.  fig.  5.) 

The  formation  of  these  nucleoli  maybe  thus  explained : — The  effect 
of  acetic  acid  is  to  contract  the  entire  corpuscle ;  on  the  nucleus, 
however,  it  would  appear  to  operate  with  such  force  as  to  occasion 
a  complete  division  of  its  substance. 

The  divided  nucleus  has  been  observed  by  many  observers  in  the 
pus  globule,  but  its  occurrence  in  the  mucous  corpuscle  has  not  been 
generally  noticed;  this  division  of  the  nucleus  has  been  considered  to 
constitute  an  exception  to  the  law  of  the  development  of  a  cell  around 
a  single  nucleus ;  whether  it  ought  to  be  so  regarded  is  doubtful,  see- 
ing that  these  multiplied  nuclei  are  usually  the  result  of  the  operation 
of  a  powerful  reagent,  and  are  but  rarely  visible,  unless  as  the  conse- 
quence of  the  application  of  some  reagent. 

Mr.  Wharton  Jones  has  endeavoured  to  meet  this  conceived 
exception,  by  supposing  that  the  nucleoli  are  all  enclosed  within  the 
membrane  of  the  nucleus.  I  have  myself,  however,  failed  to  detect 
the  existence  of  any  envelope  surrounding  the  nucleoli. 

Form. — The  form  of  the  mucous  corpuscle,  although  usually 
spherical,  is  subject  to  considerable  variety,  this  depending  frequently 
upon  the  density  of  the  fluid  in  which  it  is  immersed,  but  occasionally 
also  upon  the  amount  of  pressure  to  which  it  may  be  subjected. 

Thus,  in  fluid  which  is  very  dense,  the  operation  of  exostosis  is  set 
up  between  the  corpuscle  and  the  fluid  medium  which  surrounds  it, 
whereby  a  portion  of  its  contents  passes  into  that  medium,  as  a  con- 
sequence of  which  its  investing  membrane  collapses,  and  exhibits  a 
variety  of  forms.     (See  Plate  XI.  fig.  2.) 

Corpuscles  thus  affected  nevertheless  retain  the  power  of  reassuming 
the  form  which  properly  belongs  to  them  when  they  are  immersed  in 
Water  or  any  other  liquid,  the  density  of  which  is  less  than  that  of  the 
fluid  contained  within  the  cavity  of  the  corpuscle  itself.  (See  Plate 
XL  fig.  3.) 

The  form  of  the  mucous  corpuscle  is  also  subject  to  alteration  from 
another  cause,  viz:  pressure.     Thus,  it  is  often  seen  to  be  of  an  oval 


176  ORGANIZED     FLUIDS. 

form  in  thick  and  tenacious  mucus;  this  shape  results  from  the  pres- 
sure exercised  upon  the  corpuscles  by  the  almost  invisible  fibres  into 
which  the  fluid  part  of  mucus  resolves  itself,  and  which  often  become 
drawn  out  in  the  adjustment  of  the  mucus  on  the  port-object  of  the 
microscope.     (See  Plate  XII.  Jig.  3.) 

The  oval  shape  thus  impressed  upon  it  is  permanent,  because  the 
pressure  of  the  fibres  of  the  solid  mucus  ceases  not  to  act:  if  the 
pressure,  however,  be  direct,  and  the  corpuscle  be.  immersed  in  a 
thinnish  fluid,  it  will  resume  the  spherical  form,  the  compressing 
force  being  removed,  owing  to  the  elasticity  with  which  it  is  endowed. 

Size. — The  size  of  the  corpuscle  is  also  liable  to  much  variation, 
this  resulting  mainly  from  the  condition  of  the  fluid,  as  to  density,  in 
which  it  is  immersed. 

Thus,  in  water,  or  any  other  fluid,  the  density  of  which  is  less 
considerable  than  that  of  its  contents,  the  corpuscle  imbibes  by 
endosmosis  the  liquid  by  which  it  is  surrounded,  to  such  an  extent  as 
to  cause  it  to  exceed,  by  two  or  three  times,  its  former  dimensions. 
(See  Plate  XI.  Jig.  3.) 

By  reference,  then,  to  the  two  particulars  referred  to,  viz:  the 
density  of  the  medium  in  which  it  dwells,  and  pressure,  we  are  enabled 
to  explain  all  the  varieties  of  form  and  size  which  the  mucous  cor- 
puscle presents. 

Properties. — From  the  preceding  remarks  on  the  structure,  form, 
and  size  of  the  mucous  corpuscle,  we  perceive  that  in  all  these  par- 
ticulars, it  accords  closely  with  the  white  corpuscles  of  the  blood; 
we  shall  now  proceed  to  show  that  there  are  other  points  of  resem- 
blance between  the  two  organisms. 

Thus  reagents  affect  mucous  corpuscles  in  a  manner  precisely  similar 
to  that  in  which  they  act  upon  the  white  globules  of  the  blood;  water 
causes  them  to  increase  in  size,  acetic  acid  contracts  them  somewhat, 
and  renders  the  nucleus  and  the  molecules  more  distinct.  Between 
mucous  corpuscles  and  the  white  globules  of  the  blood  there  is,  then, 
a  structural  identity ;  but  let  us  see  if  there  be  not  also  a  Junctional 
correspondence. 

NATURE    OF    MUCOUS    CORPUSCLES. 

Mr.  Addison*  conceives  "that  mucous  and  pus  globules  are  altered 
colourless  blood-corpuscles,"  from  which  opinion  it  is  evident  that 
gentleman  believes  that  the  white  corpuscles  of  the  blood  pass  normally 
*  Transactions  of  Prov.  Med.  and  Surg.  Association,  vol.  xii.  p.  255. 


mucus.  177 

through  the  walls  of  the  blood-vessels,  although  he  does  not  appear 
satisfactorily  to  have  witnessed  the  exact  manner  of  their  escape. 

The  perfect  identity  of  organization  existing  between  the  colourless 
corpuscles  of  the  blood  and  mucous  and  pus  globules,  would  predis- 
pose the  mind  to  adopt  that  view  as  sufficient  and  correct,  which 
endeavoured  to  prove  that  they  all  had  a  common  origin  in  the  blood. 

It  must  nevertheless  be  remembered  that  the  notion  of  the  identity 
in  origin  of  the  mucous  and  pus  globule  with  the  colourless  blood- 
corpuscle,  rests  upon  the  single  supposition  that  the  latter  does  really 
escape  from  the  blood-vessels,  in  which  originally  it  is  formed. 

It  seems  to  me,  however,  that  this  statement,  to  which  I  was  myself 
at  one  time  disposed  to  attach  some  importance,  may  be  fairly  chal- 
lenged, seeing  that  the  direct  passage  of  the  white  corpuscles  of  the 
blood  appears  never  to  have  been  clearly  witnessed. 

Moreover,  the  idea  of  any  such  escape  of  the  white  corpuscles  is 
opposed  to  that  view  which  reasoning  alone  wTould  lead  one  to  enter- 
tain; thus,  if  the  colourless  corpuscles  of  the  blood  possessed  the 
power  of  escape  from  their  vessels,  no  good  reason  could  be  advanced 
why  the  red  globules  should  not  also  pass  through  them. 

If  the  capillary  vessels  terminated  by  open  mouths,  which  we  know 
that  they  do  not  in  their  normal  state,  then  indeed  it  would  be  highly 
probable  that  mucous  and  pus  corpuscles  were  the  white  corpuscles 
of  the  blood,  escaped  from  the  vessels. 

I  am  disposed,  then,  to  question  the  accuracy  of  the  view  enter- 
tained by  Mr.  Addison,  and  to  believe  that  the  globules  of  mucus  are 
formed  externally  to  the  blood-vessels;  the  mucous  glands  or  crypts 
which  are  scattered  so  abundantly  over  the  surface  of  all  mucous 
membranes,  having  a  considerable  share  in  their  formation. 

That  the  mucous-bearing  glands  are  intimately  connected  with  the 
development  of  mucous  corpuscles  seems  proved  by  the  fact,  that  the 
fluid  expressed  from  them  is  filled  with  corpuscles  of  a  smaller  size 
than  ordinary  mucous  globules,  and  destitute  of  any  admixture  with 
epithelial  scales;  these  corpuscles  certainly  could  not  have  found 
entrance  into  the  cavities  of  the  glands  from  without.  (See  Plate 
XL  ^.6.) 

The  opinion  that  the  mucous  corpuscles  are  formed  externally  to 
the  blood-vessels,  is  also  supported  by  the  observations  of  M.  Vogel, 
who  remarked  that  the  plastic  exudation  which  covers  the  surface  of 
a  recent  wound  contains,  at  first,  only  minute  granules :  these  after  a 
time  become  associated  in  two's  and  three's,  and  surrounded  by  a 

12 


178  ORGANISED      FLUIDS. 

delicate  envelope;  finally,  fully-formed  mucous  or  pus  corpuscles 
appear  in  the  liquid. 

Henle  believes  that  the  white  corpuscles  of  the  blood,  of  lymph 
and  of  chyle,  as  well  as  those  of  mucus  and  pus,  are  elementary  cells ; 
and  he  says  of  the  pus  corpuscles  that  they  are  nothing  else  than 
elementary  cells  in  process  of  being  transformed  into  those  of 
the  tissue  which  the  organism  regenerates  in  the  injured  part;  and  of 
the  white  globules  of  the  blood  he  writes,  they  are,  without  the  least 
doubt,  transformed  into  blood  corpuscles. 

This  opinion  of  Henle  accords  closely  with  that  of  Addison,  who 
believes,  as  already  stated,  that  out  of  the  white  globules  of  the  blood, 
all  other  corpuscles  met  with  in  the  body  are  formed,  the  former 
escaping  from  the  blood-vessels. 

I  also  regard  the  white  corpuscles  of  the  blood  as  elementary  or 
tissue  cells,  although  at  the  same  time  the  views  entertained  by  myself 
respecting  them  differ  from  those  both  of  Henle  and  Addison.  Thus, 
I  do  not  consider,  with  the  former,  that  the  colourless  corpuscles  are 
transformed  into  red  blood  discs,  nor  with  the  latter,  that  every  other 
cell  met  with  in  the  animal  organism,  proceeds  from  the  white 
corpuscles  of  the  blood. 

The  white  corpuscles  of  lymph,  chyle,  and  blood,  I  conceive  to  be 
transformed  into  the  epithelial  cells,  which  constitute  the  epithelium 
with  which  the  internal  surface  of  the  vessels  of  the  entire  vascular 
system  is  provided. 

The  corpuscles  of  mucus  I  conceive  to  have  an  origin  distinct 
from  the  colourless  globules  of  the  blood ;  but  in  like  manner  I  regard 
them  as  elementary  or  tissue  cells,  believing  that  they  are  finally 
developed  into  the  different  forms  of  epithelium  encountered  upon  the 
surface  of  mucous  membranes. 

The  corpuscles  of  pus  are  also  elementary  cells  and  mostly  altered 
mucous  corpuscles. 

The  view  just  expressed  as  to  the  nature  of  the  white  corpuscles 
of  the  blood,  is  one  which  has  but  recently  impressed  itself  upon  my 
mind.  It  is  not  opposed,  however,  to  the  opinion  previously  put  forth 
of  the  connexion  existing  between  these  corpuscles  and  nutrition, 
seeing  that,  whether  in  their  early  stage  of  development  as  colourless 
blood  globules,  or  in  the  more  mature  condition  of  their  growth  as 
epithelial  scales,  they  are  doubtless  to  be  regarded  as  secreting  organs, 
and  as  effecting  some  important  change  in  the  constitution  of  the 
liquor  sanguinis. 


mucus.  179 

The  only  respect  in  which  the  opinion  that  the  colourless  globules 
of  the  blood  are  converted  into  the  scales  which  "constitute  the  lining 
epithelium  of  the  vessels  is  at  variance  with  a  previously-expressed 
view,  is  in  relation  to  the  escape  of  those  globules  as  a  usual  occur- 
rence; an  opinion  of  Mr.  Addison,  in  which  I  was  formerly  disposed 
to  concur,  but  which  I  am  now  inclined  to  reject. 

A  final  reason  which  may  be  stated  for  disbelief  in  the  identity  as 
regards  the  origin  of  the  colourless  corpuscles  of  the  blood  and 
mucous  globules,  is  the  difficulty,  not  to  say  impossibility,  of  explaining 
how  these  colourless  corpuscles,  having  precisely  the  same  form  and 
origin  in  the  commencement,  should,  in  one  situation,  be  developed 
into  a  shape  and  a  structure  so  totally  dissimilar  to  that  which  the 
same  corpuscles  in  another  position  exhibit,  the  varieties  of  form  and 
structure  of  epithelial  scales  into  which  the  white  corpuscles  are 
supposed  to  be  developed  being  so  considerable. 

Mucous  globules,  then,  are  to  be  regarded  as  young  epithelial  scales, 
as  are  also  the  colourless  globules  of  the  blood;  they  both  have  a  like 
structure  and  a  corresponding  function  to  perform,  but  they  have  a 
different  origin;  thus,  the  mucous  globules  are  developed  externally  to 
the  lymphatics  and  blood-vessels,  while  the  colourless  blood  corpuscles 
are  formed  within  those  vessels. 

The  further  consideration  of  the  ulterior  development  of  mucous 
corpuscles,  or  young  epithelial  cells,  will  come  more  appropriately 
under  the  head  of  Epithelium. 

Blood  corpuscles  not  unfrequently  occur  mixed  up  with  mucous 
globules,  as  in  the  mucus  thrown  off  during  parturition  (see  Plate 
XII.  jig.  1),  and  as  in  the  rust-coloured  expectoration  of  Pneumonia. 

THE    MUCUS    OF    DIFFERENT    ORGANS. 

After  the  threefold  division  of  mucus  which  we  have  given,  founded 
upon  the  structure  of  the  membranes  by  which  it  is  secreted,  and 
after  the  description  which  has  been  entered  upon  of  the  peculiarities 
appertaining  to  the  mucus  of  each  of  those  divisions,  it  will  be 
unnecessary  to  enlarge  at  any  length  upon  the  characters  presented 
by  the  mucus  secreted  by  the  membrane  which  belongs  to  each 
particular  organ  or  part;  it  will  be  sufficient  just  to  enumerate  the 
names  of  the  membranes  by  which  each  description  of  mucus  is  fur- 
nished, and  to  point  out  any  peculiarities  which  the  mucous  secretion 
of  any  particular  organ  may  present:  this  having  been  done,  and  the 
distinctive   characters   of  the   three  forms   of  mucus   having   been 


180  ORGANIZED     FLUIDS. 

recalled  to  mind,  we  shall  then  be  in  a  position  to  assign  to  the  mucus 
of  each  locality  its  principal  characteristics. 

Thus,  the  mucus  furnished  by  the  nasal  and  bronchitic  mucous 
membranes,  and  which  may  be  called  nasal  and  bronchitic  mucus,  as 
also  that  of  the  digestive  tube,  from  the  pyloric  orifice  of  the  stomach 
unto  near  the  termination  of  the  rectum  (the  caecum  alone  excepted), 
of  the  urethra,  prostatic  gland,  vesiculae  seminales  and  the  uterus, 
belongs  to  the  first  division  of  mucus,  viz :  that  which  is  secreted  by 
the  true  mucous  membranes.     (See  Plate  XII.  fig.  3.) 

The  mucus  of  the  vagina  presents  the  best  example  of  the  mucus 
of  the  second  class,  which  is  secreted  by  the  false  mucous  membranes. 
(See  Plate  XII.  fig.  1.) 

Lastly.  The  mucus  of  the  mouth,  rectum  and  bladder,  appertains 
to  the  third  description  of  mucus,  and  which  is  supplied  by  the  mixed 
mucous  membranes.     (See  Plate  XII.  fig.  2.) 

Vaginal  and  Uterine  Leucorrhea. 

One  practical  result  arising  from  the  discrimination  of  mucus  into 
different  kinds  may  here  be  alluded  to ;  thus,  by  means  of  the  differ- 
ence in  the  microscopic  characters  of  the  mucus  secreted  by  the 
uterus  and  that  furnished  by  the  vagina,  it  is  in  our  power  to  decide, 
in  cases  of  leucorrheal  discharge,  whether  the  affection  has  its  seat 
in  the  mucous  membrane  of  the  uterus  or  in  that  of  the  vagina.  The 
mucous  membrane  of  the  uterus,  as  we  have  seen,  belongs  to  the 
class  of  true  mucous  membranes ;  that  of  the  vagina,  on  the  contrary, 
to  the  false  mucous  membranes.  Now,  if  the  leucorrhea  be  uterine, 
the  discharge  will  present  the  globules  characteristic  of  the  secretion 
produced  by  the  class  of  true  mucous  membranes ;  if,  on  the  other 
hand,  it  be  vaginal,  the  mucus  will  contain  the  epithelial  scales  which 
belong  to  the  mucus  of  false  mucous  membranes;  moreover,  the 
former  mucus  will  be  alkaline,  and  the  latter  acid. 

Effect  of  Acid  Mucus  on  the  Teeth. 

The  degree  of  acidity  presented  by  the  mucus  of  the  mouth  varies 
considerably,  according  to  the  relative  proportions  of  mucus  and 
saliva  which  exist  in  the  mouth  at  the  time  at  which  the  reaction  of 
its  secretions  is  tested,  and  which  proportion  differs  both  at  differen' 
times  of  the  day  and  in  different  states  of  the  system,  and  especiallj 
of  the  stomach.  The  mucus  of  the  mouth  we  know  to  exhibit  ir 
states  of  health  an  acid  reaction,  while  the  saliva,  on  the  contrary, 


MUCUS.  181 

manifests  an  alkaline  constitution ;  the  tendency  of  these  two  fluids 
is  therefore  to  produce  a  neutral  secretion,  and  this  explanation  will 
account  for  the  opposite  results  which  have  been  obtained  by  different 
observers.  The  best  time  to  ascertain  the  chemical  reaction  of  the 
buccal  mucus  is  in  the  morning,  when  there  is  an  accumulation  of  it 
on  the  tongue  and  around  the  gums;  and  the  best  method  of  deter- 
mining the  acid  or  alkaline  qualities  of  the  saliva,  is  first  to  scrape 
the  tongue  well,  and  as  far  as  possible  free  the  mouth  of  mucus,  and 
then  proceed  to  test  the  saliva  as  it  issues  from  the  orifices  of  its  ducts. 
A  highly  acid  condition  of  the  mucus  of  the  mouth  is  assuredly 
productive  of  injurious  effects  upon  the  teeth.  Although  this  state 
of  the  buccal  mucus  cannot  be  regarded  as  giving  rise  to  the  peculiar 
caries  to  which  the  teeth  are  so  remarkably  liable;  nevertheless,  it 
cannot  be  doubted  that  it  predisposes  the  teeth  to  this  affection,  and 
that  it  hastens  greatly  the  progress  of  the  decay  when  once  this  has 
commenced.  To  correct  the  condition  of  the  stomach,  if  it  be  faulty, 
the  internal  administration  of  alkalies  should  be  had  recourse  to;  and 
to  remedy  the  local  acidity,  tooth  powders,  composed  principally  of 
of  some  alkaline  carbonate,  should  be  employed. 

The  Vaginal  Tricho-Monas. 

M.  Donne  has  discovered  in  the  vaginal  mucus  of  women  labouring 
under  discharges,  either  specific  or  otherwise,  a  new  species  of  human 
parasite  belonging  to  the  order  of  Infusoriae.  This  animalcule, 
owing  to  its  resemblance  to  the  spherical  mucous  globules  with  which 
it  is  constantly  associated,  is  with  difficulty  discoverable  by  those 
who  are  not  practically  familiar  with  its  appearance,  and  the  mode  of 
detecting  it.  Thus,  it  presents  nearly  the  same  size,  form,  granular 
structure,  and  colour  as  the  mucous  corpuscles  alluded  to;  it  is  to  be 
distinguished  from  these,  however,  by  the  independent  locomotive 
power  which  it  possesses,  the  movements  which  it  performs  being 
produced  principally  by  means  of  a  long  lash  or  cilium  with  which 
its  anterior  extremity  is  furnished,  and  the  presence  of  which  causes 
the  animal  to  lose  somewhat  its  circular  contour,  and  assume  a  form 
approaching  the  oval ;  in  addition  to  this  long  cilium,  three  or  four 
other  shorter  cilia  exist,  which  surround  the  mouth,  and  which  can 
only  be  satisfactorily  detected  when  the  motions  of  the  animalcule 
become  somewhat  retarded.  (See  Plate  XII.  fig.  6.)  In  order  that 
it  may  be  seen  alive  and  in  active  movement,  it  is  necessary  that  the 
mucus  containing  it  should  be  submitted  to  examination  as  soon  as 


182  ORGANIZED     FLUIDS. 

possible  after  its  removal  from  the  vagina;  the  animal  once  dead,  it 
is  then  almost  impossible  to  distinguish  it  from  a  mucous  corpuscle. 

M.  Donne,  on  first  discovering  this  parasite,  was  for  some  time  in 
doubt  as  to  whether  its  occurrence  was  to  be  regarded  as  having  any 
connexion  with  the  specific  disorders  of  which  the  vagina  is  sometimes 
the  seat,  and  he  has  at  length  arrived  at  the  conclusion  that  no  such 
relation  as  that  suspected  exists,  and  that  any  inflammation,  specific 
or  otherwise,  sufficiently  active  to  give  rise  to  the  secretion  of 
puriform  matter,  may  be  accompanied  by  the  tricho-monas  which  has 
been  described. 

In  addition  to  the  positive  characters  which  have  been  indicated, 
denoting  the  presence  of  this  animalcule,  there  is  another  altogether 
indirect  which  serves  to  signalize  its  existence  in  the  vaginal  mucus, 
and  this  is  the  presence  in  it  of  air-bubbles,  which  are  not  encountered 
in  healthy  mucus. 

Vaginal  Vibrios. 

The  tricho-monas  is  not  the  only  animalcule  which  lives  in  the 
mucus  of  the  vagina;  there  are  frequently  met  with  in  it  minute 
vibrios,  which,  to  be  satisfactorily  seen,  require  to  be  viewed  with  a 
magnifying  power  of  not  less  than  the  ji?  of  an  inch. 

In  the  same  manner  as  the  tricho-monas,  they  always  occur  in 
connexion  with  pus  globules ;  they  are  not,  however,  any  more  than 
the  tricho-monas,  to  be  regarded  as  indicating  the  existence  of  specific 
or  venereal  affections,  although  they  are  not  unfrequently  met  with 
in  the  secretion  of  chancres  of  an  undoubtedly  specific  character. 


pus.  183 


ART.    IV.    PUS. 


GENERAL    CHARACTERS. 


Healthy,  phlegmonous,  or  laudable  pus,  is  a  fluid  of  the  colour 
and  consistence  of  cream,  readily  miscible  with  water,  in  which  after 
a  time  it  sinks;  it  does  not  admit  of  being  drawn  out  into  threads, 
and  exhibits  usually  an  alkaline,  though  sometimes  an  acid,  reaction. 

Like  mucus,  which  it  resembles  so  closely,  pus  is  made  up  of  two 
constituents,  the  one  fluid,  the  other  solid;  these,  if  allowed  to  stand 
at  rest  for  a  time,  will  undergo  a  spontaneous  separation  from  each 
other,  the  corpuscles  subsiding  to  the  bottom,  and  the  fluid  or  serum 
floating  upon  the  top;  this  also  will  be  frequently  observed  to  be 
covered  with  a  delicate  film  composed  of  oil  globules.  The  fluid 
portion  of  pus,  as  of  mucus,  is  probably  the  only  essential,  as  it 
certainly  is  its  only  distinctive  constituent;  but  while  the  latter  is 
sometimes  free  from  globules,  the  former  is  never  without  a  greater 
or  less  amount  of  corpuscles,  on  the  presence  and  numbers  of  which 
its  opacity,  its  colour,  and  its  consistence  mainly  depend. 

The  general  characters  of  pus,  however,  undergo  many  changes  in 
disease;  thus  its  consistence,  colour,  smell,  and  all  other  sensible 
qualities,  vary  greatly  in  pathological  conditions. 

IDENTITY    OF    THE    PUS    AND    MUCOUS    CORPUSCLE. 

The  globules  of  pus  resemble  in  all  essential  particulars  those  of 
true  mucus,  the  characters  of  which  have  been  already  described; 
thus,  they  present  the  same  form,  the  same  constitution,  and  they 
comport  themselves  in  a  manner  almost  identical  with  chemical 
reagents.     (See  Plate  XI.  fig.  1,  and  Plate  XIII.  fig.  1.) 

In  one  respect  only  can  a  difference  in  the  effect  of  reagents  on  the 
pus  and  mucous  corpuscles  be  detected;  this  difference  is,  however, 
one  of  degree,  and  not  of  kind;  thus,  the  mucous  corpuscle  is  less 
readily  acted  upon  by  the  acids  than  the  pus  globule;  in  the  former, 
a  solution  of  acetic  acid,  not  too  concentrated,  will  often  disclose  but 
a  single,  although  large,  nucleus ;  while  the  same  solution  applied  to  the 
latter,  will  render  apparent  seldom  less  than  three  or  four  nucleoli. 
(See  Plate  XIII.  fig.  2.)  This  is,  however,  by  no  means  a  constant 
result,  and  the  effect  of  the  application  of  strong  acetic  acid  to  the 
mucous  globule  is  almost  invariably  to  render  apparent  three  or  four 


184  ORGANIZED     FLUIDS. 

nucleoli;  so  that,  from  the  circumstance  of  the  number  ot  nuclei 
disclosed  by  acetic  acid,  no  opinion  can  be  formed  as  to  the  nature 
of  the  corpuscle,  whether  it  be  a  mucous  or  a  pus  corpuscle.  Of  the 
accuracy  of  this  view,  notwithstanding  that  a  contrary  opinion  is 
held  by  many  observers,  not  a  doubt  can  be  entertained. 

It  is  not  in  every  example  of  pus  that  we  find  the  well-formed  and 
spherical  corpuscles,  which  characterize  healthy  and  normal  pus.  In 
the  pus  which  has  been  long  secreted,  as  in  that  of  old  abscesses,  we 
find  but  few  corpuscles,  the  majority  being  broken  up  and  reduced  to 
their  elementary  particles.     (See  Plate  XIII.  fig.  5.) 

The  best  examples  of  pus  corpuscles  are  seen  in  pus  which  has 
been  recently  secreted,  as  in  that  just  formed  on  some  healthy 
granulating  surface.     (See  Plate  XIII.  fig.  1.) 

When,  therefore,  pus  and  mucous  globules  are  spoken  of,  it  is  not 
to  be  understood  that  these  terms  indicate  two  distinct  structures, 
but  merely  the  occurrence  of  the  same  solid  element  in  two  fluids, 
which,  although  usually  presenting  some  points  of  difference,  are  in 
all  probability  not  essentially  distinct. 

THE    NATURE,    ORIGIN,    AND    FORMATION    OF    PUS    CORPUSCLES. 

In  having  indicated  the  nature  of  mucous  globules,  we  have  also, 
to  a  very  great  extent,  pointed  out  that  of  pus  corpuscles,  seeing  that 
the  corpuscles  of  both  have  an  organization  precisely  similar. 

One  of  the  earliest  opinions  formed  in  reference  to  the  nature  of 
pus  was,  that  it  was  constituted  of  blood  deprived  of  its  colouring 
matter,  a  view  which  was  entertained  even  before  the  discovery  of 
the  blood  corpuscles  themselves. 

Subsequently  to  the  period  of  the  detection  of  the  red  corpuscles 
in  the  blood,  many  observers  have  conceived  that  pus  consists  of 
these  corpuscles  altered  merely  in  colour. 

A  third  opinion  in  reference  to  the  formation  of  pus  and  mucous 
globules  is  that  of  Vogel,  who  maintained  that  they  arose  out  of  a 
transformation  of  the  epithelium,  the  nuclei  of  which  constituted  the 
corpuscles.  This  view,  although  not  without  ingenuity,  has  but  little 
even  of  probability  to  recommend  it,  and  it  will  be  perceived  that  it 
is  the  very  reverse  opinion  to  that  which  is  maintained  in  these  pages, 
and  which  is,  that  the  epithelium  is  itself  derived  from  mucous  and 
pus  globules. 

We  have  already,  under  the  head  of  Mucus,  adverted  to  the 
opinion  of  Addison,  that  mucous  and  pus  globules  are  altered  colour- 


pus.  185 

less  blood  corpuscles,  an  opinion  which  we  have  also  endeavoured  to 
refute,  principally  by  reference  to  the  impossibility,  save  from  lesion, 
of  the  escape  of  the  white  corpuscles  from  their  containing  vessels. 

Reference  has  also  been  made  to  the  view  entertained  by  Henle 
respecting  the  nature  of  pus  corpuscles,  who  says  of  them  that  they 
are  nothing  else  than  elementary  cells  in  process  of  being  trans- 
formed into  those  of  the  tissue,  which  the  organism  regenerates  in 
the  injured  part. 

I  also  agree  with  Henle  in  considering  pus  corpuscles  to  be 
elementary  cells,  but  I  differ  from  him  in  not  regarding  them  as 
representing  the  cells  of  the  tissue  in  which  the  pus  is  formed. 

Pus  corpuscles  I  conceive  to  be  identical  with  mucous  corpuscles, 
and  these  again  are  to  be  regarded  as  repi'esenting  an  early  stage  in 
the  development  of  epithelial  scales. 

Further,  it  is  here  supposed  that  the  formation  of  pus  is  to  be 
viewed  in  the  light  of  a  salutary  process,  and  as  indicating  the  effort 
on  the  part  of  the  organism,  where  suppuration  occurs  as  the  result  of 
lesion  of  any  kind,  to  repair  the  mischief  sustained,  and  which  it 
does  by  the  elaboration  of  pus  corpuscles  capable  of  being  transformed 
into  a  protecting  epithelium. 

In  support  of  this  view,  reference  may  be  made  to  the  fact  that  it  is 
by  no  means  uncommon  to  encounter  epithelial  scales  mixed  up  with 
the  ordinary  pus  corpuscles  contained  within  the  cavity  of  an 
abscess,  or  covering  the  surface  of  an  old  ulcer. 

But,  it  may  be  asked,  how  happens  it  then  that  all  pus  corpuscles 
do  not  become  converted  into  epithelial  scales,  and  that  so  many  of 
them  are  discharged  or  thrown  off  from  the  system  without  attaining 
to  the  higher  degree  of  development  of  which  they  are  stated  to  be 
susceptible  ? 

This  arrest  of  development  doubtless  arises  from  the  rapidity  with 
which  the  pus  corpuscles  are  formed,  and  which  is  indicative  of  the 
strength  of  the  Vis  medicatrix  naturce,  the  result  of  which  is  that  the 
earlier  formed  corpuscles  become  displaced  by  the  more  recently 
developed  ones,  and  are  thus  removed  without  the  sphere  of  growth, 
in  consequence  of  which  they  perish. 

Having  thus  considered  the  nature  of  pus  corpuscles,  we  will  next 
endeavour  to  form  some  opinion  in  reference  to  their  origin  and  mode 
of  formation;  in  these  respects  also  an  essential  correspondence 
doubtless  exists  between  pus  and  mucous  globules. 

Mandl  attributes  to  the  pus  globule  the  same  mode  of  formation 


1S6  ORGANIZED     FLUIDS. 

which  he  has  described  as  belonging  to  the  white  corpuscles  of  the 
blood,  that  is,  that  they  are  formed  external  to  the  vessels  by  the 
aggregation  of  molecules  precipitated  from  the  fibrin,  and  hence 
Mandl  terms  both  the  white  and  pus  corpuscles  "fibrinous  globules." 

This  view  of  the  formation  of  pus  corpuscles  is  supported  also  by 
the  observations  of  Vogel  (already  cited)  made  upon  abraded  surfaces. 

Mandl,  therefore,  is  most  probably  correct  in  his  opinion  as  to  the 
mode  of  formation  of  pus  corpuscles,  viz:  by  precipitation;  but  it  is 
at  the  same  time  almost  certain  that  they  are  not  constituted  of  fibrin, 
as  supposed  by  that  micrographer :  this  may  be  inferred  from  the 
different  manner  in  which  acetic  acid  acts  upon  fibrin  and  pus 
corpuscles;  thus,  the  former  swells  up,  and  is  rendered  soft  and  friable 
by  its  application,  while  the  latter  under  its  influence  become  smaller, 
and  their  contained  molecules  more  distinct. 

Donne  dissents  from  Mandl's  view  altogether.  At  page  191  of  the 
Cours  de  Microscopie,  M.  Donne  expresses  himself  as  follows: — 
"Thus  I  do  not  admit  that  the  globules  of  pus  are  formed  at  the 
expense  of  the  fibrin  of  the  blood ;  that  they  ought  to  be  considered 
as  a  sort  of  precipitate  of  the  fibrinous  part  of  the  fluid  blood;  and  in 
spite  of  their  analogy  of  structure  and  composition  with  the  white 
globules  of  the  blood,  I  nevertheless  do  not  admit  that  they  have  any 
thing  in  common  in  their  origin  and  in  their  intimate  nature  .with 
these  last.  I  regard  the  globules  of  pus  as  a  product  of  special 
secretion  direct  from  the  pus  forming  membrane." 

There  appears  to  me  to  be  much  of  error  in  the  preceding  observa- 
tions: there  is  doubtless  very  much  in  common  between  the  white 
corpuscles  of  the  blood  and  pus  globules,  viz:  a  common  mode  of 
formation  and  a  common  function  to  perform. 

At  the  same  time  it  must  be  admitted,  with  Donne,  that  the  surface 
or  membrane,  from  which  the  pus  proceeds,  is  also  intimately  associated 
with  the  development  of  the  pus  corpuscles. 

DISTINCTIVE    CHARACTERS    OF    MUCUS    AND    PUS. 

We  have  now  to  ask  ourselves  the  question,  which  doubtless  many 
have  applied  to  themselves  before,  viz:  what  are  the  distinctive 
characters  between  mucus  and  pus  revealed  to  us  by  the  microscope, 
and  the  satisfactory  recognition  of  which  has  been  deemed  to  be  of  so 
much  importance? 

To  this  inquiry  no  sufficient  answer  has  as  yet  been  returned:  this 
difficulty  the  microscope  has  failed  to  solve;  and  this,  in  all  probability, 


pus.  1S7 

for  the  very  adequate  reason,  that  between  the  fluids  in  which  a 
distinction  has  been  sought,  no  microscopic  difference  exists.  The 
inquiry  has  been  made  on  the  false  assumption  that  mucus  and  pus 
are  really  essentially  distinct ;  and  its  importance  has  been  magnified 
by  the  idea  that  it  would  impart,  as  indeed  it  undoubtedly  would  do, 
if  real,  increased  assistance  in  the  diagnosis  of  disease. 

Since,  however,  the  establishment  of  the  fact  that  pus  may  be 
formed  independently  of  any  appreciable  structural  lesion,  much  of 
the  interest  which  was  supposed  to  attach  to  this  inquiry  has  been 
lost,  and  that  which  still  appertains  to  it  has  been  further  lessened  by 
the  demonstration  at  which  we  have  arrived  by  means  of  the  micro- 
scope, of  the  perfect  identity  of  pus  and  mucous  corpuscles. 

Now,  the  manifestation  of  this  identity  by  the  microscope  is  not 
less  a  triumph  of  that  instrument  than  if  it  had  really  proved  that  the 
notion  of  physiologists  was  actually  founded  on  fact,  and  that  there 
does  really  exist  a  tangible  difference  in  the  microscopic  characters 
of  the  two  fluids. 

Notwithstanding  the  absence  of  any  positive  known  microscopic 
character,  whereby  at  all  times,  and  in  all  conditions,  pus  may  be 
discriminated  from  mucus,  this  want  of  knowledge,  arising  from  the 
very  sufficient  fact  to  which  allusion  has  already  been  made,  viz: 
that  no  such  character  really  exists,  the  two  fluids  under  discussion 
may  frequently  be  distinguished,  at  a  glance,  by  certain  outward  and 
physical  properties  and  appearances,  and  this  is  especially  the  case 
when  they  occur  without  admixture  with  each  other. 

These  differences  in  the  outward  character  of  the  two  fluids  are 
not  always,  however,  equal  to  their  discrimination,  and  which  arises 
from  the  fact,  that  they  are  all  of  them  subject  to  the  greatest  possible 
variation,  so  that  there  is  not  one  which  can  be  regarded  as  truly 
distinctive.  Thus,  in  morbid  conditions,  the  one  fluid  will  pass  by 
insensible  degrees  into  the  other,  or  they  will  both  be  mingled  together 
in  such  proportions  as  to  set  at  defiance  all  physical  means  employed 
to  distinguish  them. 

But  it  may  be  said  that  the  chemist  can  at  all  times  distinguish  pus 
from  mucus:  there  can  be  no  doubt  but  that,  when  all  other  means 
have  failed,  he  can  occasionally  arrive  at  a  tolerably  accurate  con- 
clusion, but  it  is  conceived  that  his  powers  in  this  respect  are  also 
limited. 

Now,  the  physical  and  chemical  difficulties  encountered  in  the 
endeavour  to  discriminate  pus  from  mucus  arise  in  all  probability, 


188  ORGANIZED     FLUIDS. 

from  the  same  cause  which  rendered  it  microscopically  impossible  so 
to  do,  viz :  that  no  constant  or  essential  difference  does  really  belong 
to  these  fluids,  whereby  at  all  times  they  may  be  characterized. 

Normal  mucus  and  pus  may  be  contrasted  as  follows :  Mucus  is 
a  thick,  tenacious,  and  transparent  substance,  easily  admitting  of 
being  drawn  out  into  threads,  not  readily  miscible  with  water,  in 
which  it  floats,  not  so  much  from  its  less  specific  gravity  as  from  the 
circumstance  of  its  great  tenacity,  allowing  it  to  retain  in  its  substance 
numerous  air  globules,  which  thus  render  it  specifically  lighter  than  the 
water:  it  exhibits  sometimes  an  acid,  and  sometimes  an  alkaline  reac- 
tion, according  to  the  nature  of  the  surface  from  which  it  proceeds ; 
and  it  contains  imbedded  in  its  substance  solid  particles  of  two  forms, 
globules  and  scales:  the  former  are  present  in  alkaline  mucus,  the 
latter  in  that  which  manifests  an  acid  reaction. 

Pus,  on  the  contrary,  is  a  thick,  opaque,  somewhat  oily  substance, 
which  does  not  admit  of  being  drawn  out  into  threads,  is  readily 
miscible  with  water,  in  which  it  sinks ;  its  chemical  reaction  varies, 
being  sometimes  alkaline,  at  others  acid :  the  solid  particles  which  it 
contains  are  mostly  of  one  kind,  globules :  these  are  always  very 
abundant,  and  float  freely  in  the  fluid  portion  of  the  pus,  while  in  that 
of  mucus    they  are  unable  to  do  so  on  account  of  its  tenacity. 

Healthy  mucus  and  pus,  when  thus  contrasted,  may  frequently  be 
distinguished  from  each  other,  but  it  is  in  unhealthy  conditions  of 
these  two  fluids,  and  especially  when  they  occur  mixed  together  in 
variable  proportions,  that  the  difficulty  of  discrimination  is  felt,  and 
that  the  want  of  a  certain  and  positive  character,  whereby  the 
diagnosis  may  be  always  established,  is  experienced. 

This  mixture  of  mucus  and  pus  may  actually  exist,  or  it  may  not, 
in  cases  of  suspected  phthisis,  in  which  sputa  are  present.  Now,  it  is 
in  cases  of  this  description  that  we  recognise  the  importance  of  the 
discrimination  of  these  substances,  and  it  is  precisely  in  these  and 
similar  instances  that  the  microscope  utterly  fails  us,  for  the  want  of 
an  ascertained  and  tangible  difference  in  the  two  fluids  submitted  to 
the  test  of  its  powers. 

Even  the  most  marked  physical  qualities  of  pus,  such  as  its  opacity 
and  tenuity,  may  all  be  effaced  by  the  employment  of  certain  reagents, 
and  converted  into  those  which  are  characteristic  of  mucus;  thus, 
pus,  by  the  addition  to  it  of  liquor  potasses  or  of  ammonia,  is  rendered 
transparent,  and  is  transformed  into  a  thick  and  tenacious  substance, 
resembling  mucus  closely.     This  singular  fact  has  been  noticed  by 


pus.  189 

both  Addison  and  Donne,  and  on  it  the  former  clever  observer  has 
built  a  theory  remarkable  for  its  ingenuity,  but  which  is  here,  never- 
theless, deemed  to  be  incorrect. 

The  change  of  pus,  from  an  opaque  substance  to  a  transparent  one, 
doubtless  results  from  the  solution  of  the  pus  corpuscles,  and  to  the 
presence  of  which  the  colour  and  opacity  of  pus  is  due ;  of  the 
increased  density  and  tenacity  of  the  pus  thus  treated,  it  is  less  easy 
to  afford  a  satisfactory  explanation. 

Addison  thus  accounts  for  it:  The  mucus  and  pus  globules,  he  says, 
contain  filaments  imbedded  in  a  fluid;  these. the  liquor  potasses  sets 
free  by  dissolving  the  envelopes  of  the  corpuscles,  and  it  is  upon  these 
filaments  that  the  tenacity  of  mucus,  and  of  pus  so  acted  upon, 
depends.  Mr.  Addison,  however,  carries  his  reasoning  upon  the  fact 
of  the  conversion  of  pus  into  a  fibrillating  substance  similar  to  mucus 
still  further.  The  white  corpuscles  of  the  blood,  he  states,  also 
contain  fibres,  and  that  these  corpuscles,  immediately  on  their  abstrac- 
tion from  the  system,  burst,  giving  issue  to  the  contained  filaments. 

These  filaments  he  conceives  to  constitute  the  fibrin  of  the  blood, 
which  he  declares  does  not  exist  in  that  fluid  as  fibrin,  but  is  only 
liberated  from  the  corpuscles  after  the  abstraction  of  the  blood  from 
the  system. 

The  entire  of  this  theory  is  here  conceived  to  be  erroneous,  and 
this  for  the  following  reasons : 

1.  The  existence  of  such  filaments  in  the  white  corpuscles  has  not 
been  proved. 

2.  The  bursting  of  these  corpuscles,  referred  to  by  Mr.  Addison, 
is  an  occurrence  which  is  rarely,  if  ever,  seen  to  take  place  while 
they  remain  imbedded  in  the  liquor  sanguinis. 

3.  The  actual  consolidation  of  the  fluid  fibrin  may  be  witnessed  to 
occur  on  the  field  by  the  microscope  in  a  drop  of  blood,  and  wholly 
independent  of  any  rupture  of  the  white  corpuscles,  which  remain 
without  appreciable  alteration. 

There  is  some  consolation,  however,  in  knowing  that  this  inquiry 
is  not  of  so  much  importance  as  it  would  appear;  for  even  were  we 
able  to  make  the  distinction  which  has  been  the  subject  of  so  many 
anxious  thoughts,  and  decide  that  pus  did  exist  in  the  sputa,  yet  this 
fact,  viewed  separately,  would  not  prove  that  disease  of  the  lungs  did 
really  exist,  since  it  is  ascertained  that  pus  may  be  formed  without 
any  structural  lesion;  and,  further,  if  lesion  were  really  present,  it 
would  not  necessarily  follow  that  this  had  its  seat  in  the  cells  of  the 


190  ORGANIZED     FLUIDS. 

lungs,  for  it  might  be  situated  either  in  the  bronchi  or  larynx.  Thus, 
even  in  this  supposed  case,  the  diagnosis  would  be  subject  to  consider- 
able uncertainty. 

Various  opinions  have  been  expressed  by  different  observers  in 
favour  of  the  possibility  of  distinguishing  pus  from  mucus.  To  some 
of  these  we  will  now  refer. 

There  is  always  met  with  in  pus,  in  greater  or  less  quantity,  globules 
of  oil;  the  presence  of  these  was  conceived  by  Gueterboch  to  afford 
a  sign,  absolutely  distinctive,  between  pus  and  mucus ;  that  they  are 
not  so,  however,  is  proved  by  the  fact  that  similar  globules  are 
occasionally  encountered  in  normal  mucus. 

Weber  conceived  the  idea  that  the  fluids  might  be  distinguished  by 
the  size  of  the  globules  contained  in  them,  the  pus  globule  being  twice 
as  large  as  that  of  mucus :  this  character  is  likewise  too  uncertain, 
and  too  variable  for  the  purposes  of  discrimination. 

Lastly,  Gruithuisen  indicated,  in  solutions  of  pus  and  mucus  in 
water,  certain  animalculae;  those  generated  in  the  former  being 
different  from  those  formed  in  the  latter  solution.  By  means  of  these 
he  asserted  that  pus  might  always  be  known  from  mucus;  but  the 
infusoria  described  by  him  are  not  confined  to  the  fluids  in  question, 
but  are  such  as  are  formed  almost  indifferently  in  any  solution  of 
animal  matter.  It  would  appear,  then,  that  up  to  the  present  time  no 
satisfactory  and  direct  means  of  distinguishing  pus  from  mucus  have 
been  detected,  and  this  for  the  reason  assigned,  that  the  two  fluids  are 
essentially  identical. 

DISTINCTIONS    BETWEEN    CERTAIN    FORMS    OF    MUCUS    AND    PUS. 

Although  it  is  impossible  to  discriminate  between  true  mucus  and 
pus  by  means  of  the  microscope  in  a  positive  manner,  we  are  yet 
enabled  to  distinguish  with  that  instrument  false  mucus  from  pus, 
because  in  this  mucus  the  corpuscles  exist  in  their  fully  developed 
form  of  tesselate  epithelium.  Now,  this  power  of  discrimination  is 
not  without  importance,  as  will  be  perceived  immediately. 

Many  persons  on  arising  in  the  morning  are  in  the  habit  of  expec- 
torating more  or  less  of  a  substance  bearing  much  resemblance  to 
pus.  This  habitual  occurrence  is  not  unfrequently  a  source  of  much 
uneasiness,  not  merely  to  the  person  the  subject  of  it,  but  also  to  his 
medical  adviser  whom  he  is  led  to  consult  upon  it. 

Now,  in  such  cases  as  these,  it  is  often  in  our  power  to  dispel  the 
anxiety  of  our  patient  and  our  own  at  the  same  time ;  for  the  solid 


pus.  191 

constituents  of  such  sputa  are  frequently  found  to  consist  almost 
entirely  of  epithelial  cells,  in  which  case  we  may  safely  pronounce 
that  they  are  not  purulent;  if,  on  the  contrary,  the  sputa  contain  only 
globules,  the  evidence  which  this  fact  would  furnish,  although  appar- 
ently, and  indeed  most  probably,  unfavourable,  would  still  be  but  of  a 
doubtful  nature. 

Again,  the  microscope  will  frequently  determine  the  nature  of  a 
suspected  fluid,  by  indicating  in  it  the  existence  of  shreds  of  cellular 
tissue,  muscular  fibrillae,  and  a  variety  of  other  organisms  which  enter 
into  the  formation  of  the  human  body;  and  by  the  presence  of  one 
or  more  of  which,  not  merely  the  nature  of  the  puriform  matter  may 
be  ascertained,  but  also  the  locality  from  which  the  pus  had  itself 
proceeded. 

DETECTION    OF    PUS    IN    THE    BLOOD. 

From  what  has  been  said  in  reference  to  the  structural  identity  ot 
the  white  corpuscle  of  the  blood  with  that  of  mucus  and  pus,  we  are 
prepared  for  the  announcement  that  no  known  characters  exist 
whereby  the  presence  of  pus  in  the  blood  may  be  established  by  the 
microscopic  examination  of  that  fluid. 

That  the  elements  of  pus  in  some  cases  are  really  present  in  the 
blood,  circulating  with  it,  scarcely  admits  of  a  single  doubt,  since  it 
is  not  unfrequently  met  with  in  situations,  such  as  on  the  lining 
membranes  of  the  vessels,  where  it  is  utterly  impossible  for  it  to 
remain  without  some  portion  of  it  becoming  commingled  with  the  blood. 

The  same  fact  is  also  proved  by  the  spontaneous  absorption  ot 
large  collections  of  matter,  an  occurrence  which  is  not  unfrequently 
witnessed,  and  which  is  only  to  be  accounted  for  on  the  assumption 
that  the  elements  of  pus  are  again  absorbed  into  the  blood  from 
which  originally  they  were  derived. 

There  can  scarcely  be  a  question,  then,  that  pus  is  occasionally 
contained  in  the  living  blood,  although  we  possess  only  indirect 
means  of  establishing  this  fact ;  and  according  to  the  views  here 
entertained,  it  may  be  present  in  the  blood  in  two  ways:  thus,  as  we 
have  seen,  it  may  be  formed  in  the  blood-vessels  themselves,  or  it 
may  be  formed  without  those  vessels,  and  again  reabsorbed  into  the 
blood  from  which  in  every  case  it  almost  immediately  proceeds. 

But  pus,  as  we  know,  is  composed  of  two  elements,  the  one  fluid, 
the  other  solid,  the  globules.  Now,  we  must  not  expect  to  see  pus 
circulating  in  the  blood  as  pus,  although  that  liquid  may  contain  all 


192  ORGANIZED     FLUIDS. 

the  elements  of  pus:  the  fluid  portion  of  course,  as  soon  as  it  enters 
the  circulation,  is  dissipated,  the  solid  alone  remaining,  and  this  does 
not  constitute  pus,  but  is  only  one  element  in  the  constitution  of 
that  fluid. 

In  certain  states  of  disease,  the  presence  in  the  vessels  of  an 
unusual  number  of  white  corpuscles  has  been  observed;  now  it  is 
but  little  probable,  that  these  are  derived  from  the  reabsorption  of 
pus,  which  had  been  previously  formed  without  those  vessels ;  it  is 
more  natural,  and  more  consonant  with  known  facts,  to  suppose,  that 
this  accumulation  is  to  be  regarded  as  an  indication  that  the  disposi- 
tion to  the  formation  of  pus,  on  the  part  of  the  blood  and  of  the 
system,  exists  to  an  unusual  extent,  and  that  such  a  condition  of  the 
vital  fluid  always  precedes  sudden  and  extensive  purulent  collections. 

Except  in  the  case  of  the  formation  of  pus  in  the  blood-vessels 
themselves,  it  is  scarcely  possible  to  suppose  that  the  pus  corpuscles 
are  taken  bodily  into  the  circulation  again;  but  it  would  rather 
appear,  from  the  condition  of  pus  in  most  abscesses,  that  the  corpuscles 
become  disintegrated  and  reduced  to  their  elementary  particles,  and 
that  thus  they  enter  the  circulation  again  in  a  fluid  state. 

The  artificial  admixture  of  pus  with  the  blood  immediately  after 
its  escape  from  a  vein,  and  before  its  coagulation  has  commenced,  is 
productive  of  somewhat  singular  results.  The  clot  formed  in  blood, 
which  has  been  mixed  with  one  quarter  part  of  its  own  quantity  of 
pus,  is  soft,  diffluent,  and  dark  coloured,  sometimes  almost  livid,  and 
the  red  corpuscles  are  found  to  be  wrinkled  and  deformed,  part  of 
their  colouring  matter  having  escaped  from  them  and  passed 
into  the  serum. 

These  changes  ensue  in  from  twenty-four  to  forty-eight  hours,  and 
possibly  result  from  the  state  of  decomposition  in  which  the  pus  itself 
might  have  been  when  introduced  into  the  blood,  and  which  condition 
it  communicated  to  the  mass  of  the  blood  itself. 


There  are  many  substances  and  fluids  having  resemblance  to  pus 
which  are  not  really  purulent;  thus,  softened  clots  of  fibrin,  which 
are  so  frequently  encountered,  especially  in  phlebitis,  bear  the  closest 
possible  similitude  to  true  pus  in  general  appearance,  and  yet  in  their 
intimate  structure  they  are  totally  dissimilar,  as  may  be  clearly 
determined  by  means  of  the  microscope. 

If  a  portion  of  softened  fibrin  be  examined  microscopically,  it  will 


pus.  193 

be  found  to  be  made  up  of  a  granular  material,  from  which  pus 
corpuscles,  or  corpuscles  similar  to  them,  are  either  entirely  absent, 
or  in  which  they  occur  but  in  very  small  numbers.  Now,  with  true 
pus,  the  reverse  is  the  case;  the  corpuscles  are  its  chief  and  most 
conspicuous  element. 

It  is  only  by  means  of  the  microscope  that  the  nature  of  softened 
fibrin  can  be  ascertained;  until  within  the  last  few  years  it  has  always 
been  mistaken  for  true  pus,  and  the  occurrence  of  masses  of  fibrin 
thus  altered  in  the  blood-vessels  has  led  to  the  opinion  that  the 
formation  of  pus  in  them  is  not  an  unfrequent  event. 

On  the  other  hand,  fluids  are  sometimes  met  with  which  look  very 
unlike  proper  pus,  and  which  are  yet  found  on  examination  to  be 
veritable  pus.  These  facts  show  the  necessity  of  a  careful  microscopic 
examination  in  all  important  and  doubtful  cases. 

METASTATIC    ABSCESSES. 

Another  notion,  the  erroneousness  of  which  has  been  rendered 
manifest  by  means  of  the  microscope,  is  that  which  has  been  enter- 
tained in  reference  to  the  removal  of  an  abscess  seated  in  one  part  of 
the  body,  and  its  subsequent  deposition  in  another  situation. 

The  knowledge  of  the  existence  of  pus  corpuscles  in  the  fluid  of 
abscesses,  and  the  fact  that  no  channels  exist  by  which  they  can  be 
conveyed  bodily  from  one  part  of  the  system  to  another,  clearly  show 
that  any  such  translation  of  the  matter  of  an  abscess  as  that 
presumed  is  an  occurrence  beyond  the  range  of  possibility. 

Abscesses  may  indeed  be  reabsorbed  into  the  system,  as  daily 
observation  teaches  us  to  be  the  case,  and  other  purulent  depositions 
take  place  subsequently  to  the  resorption  of  the  matter  of  the  first 
abscess ;  but  the  elements  of  pus,  and  assuredly  its  solid  constituents, 
are  not  carried  into  the  constitution  bodily  and  without  alteration; 
the  corpuscles  doubtless  become  disaggregated,  and  in  all  probability 
reduced  to  a  fluid  state  previous  to  absorption,  so  that  it  cannot  be 
the  same  purulent  matter  which  constitutes  the  pus  of  supposed 
metastatic  abscess. 

The  simultaneous  or  consecutive  occurrence  of  abscesses  in 
different  parts  of  the  body,  may  be  satisfactorily  explained  by  reference 
to  the  condition  of  the  system,  or  perhaps  more  immediately  of  the 
blood  itself,  which  is  evidently  charged  with  purulent  matter,  and  of 
which  it.  relieves  itself  by  the  formation  of  abscesses. 

13 


194  ORGANIZED     FLUIDS. 

VENEREAL    VIBRIOS. 

M.  Donne  has  discovered  in-  the  pus  of  syphilitic  primitive 
ulcerations,  and  of  chancres  which  have  not  been  treated  with  topical 
applications,   numerous  vibrios    of  excessive    tenuity.     (See    Plate 

XIII.  fig.  6.) 

These  vibrios  are  not  encountered  in  the  pus  of  secondary 
chancres,  nor  even  in  that  of  buboes,  which,  according  to  the 
experiments  of  M.  Ricord,  is  capable  of  giving  origin  to  a  chancre 
by  inoculation. 

Neither  are  they  to  be  met  with  in  the  pus  proceeding  from 
wounds,  nor  in  fetid  pus  altered  by  the  contact  of  the  air. 

Again,  in  the  instances  in  which  suppuration  has  been  artificially 
excited  around  the  edge  of  the  glans  penis,  the  ordinary  situation  of 
primary  syphilitic  ulcerations,  the  vibrios  are  invariably  found  to  be 
wanting  in  the  discharge  thus  created.  This  experiment  proves  that 
locality  has  nothing  to  do  with  the  development  of  the  vibrios. 

Finally,  if  inoculation  be  practised  with  the  pus  of  a  chancre 
containing  the  vibrios,  the  matter  of  the  pustule  resulting  from  the 
inoculation  will  also  be  found  to  contain  the  animalcules. 

Now,  the  inference  to  be  deduced  from  these  several  facts  and 
experiments  is,  that  if  the  vibrios  in  question  be  not  intimately 
connected  with  the  propagation  of  the  syphilitic  virus,  that  the  matter 
of  syphilis  is  at  least  peculiarly  fitted  for  their  development. 

It  is  probable  that  the  presence  of  these  vibrios  accounts,  in  a 
great  measure,  for  the  beneficial  effects  of  topical  applications, 
which  act  by  killing  the  animalcules. 


MILK.  195 


ART.  V.— MILK. 


The  general  aspect  and  qualities  of  milk  are  known  to  all;  they 
need  not  therefore  be  here  detailed. 

Healthy  and  fresh  milk,  when  submitted  to  the  action  of  test  paper, 
exhibits  an  alkaline  reaction:  in  states  of  disease,  however,  and  some 
time  after  its  removal  from  the  mammary  gland,  it  frequently 
manifests  more  or  less  of  an  acid  reaction. 

Like  the  other  fluids  which  have  as  yet  been  described  in  this 
work,  milk  is  made  up  of  two  distinct  elements,  the  one  fluid,  the 
serum — the  other  solid,  the  globules;  these,  a  few  hours  after  its 
abstraction  from  the  system,  and  when  left  at  rest,  undergo  to  a 
certain  extent  a  spontaneous  separation  from  each  other,  the  larger 
globules,  ascending  to  the  surface,  forming  a  scum  or  cream,  while 
the  smaller  remain  diffused  through  the  subjacent  serum. 

The  following  analyses  will  serve  to  give  an  idea  of  the 
composition  of  milk. 

The  relative  proportions  of  the  organic  constituents  of  human 
milk  are  thus  estimated  by  Simon : 
88  •  06  water. 
3 '  70  caseine. 
4  "54  sugar. 
3  •  40  butter. 

0*30  salts,  extractives,  &c. 
The  inorganic  components  of  the  milk  of  the  cow  are  computed 
as  follows  by  Haidlen : 

Chloride  of  sodium  -  -  0  ■  024. 

Chloride  of  potassium        -  -0144. 

Soda  -  -  -  -0-042. 

Phosphate  of  lime  -  -  0'231. 

Phosphate  of  magnesia      -  -  0  ■  042. 

Phosphate  of  the  peroxide  of  iron  -  0*007. 
From  the  above  brief  sketch  of  the  constitution  of  the  milk,  it  will 
be  seen  that  a  very  close  analogy  exists  between  that  fluid  and  the 
blood :  like  it,  the  milk  is  made  up  of  two  parts — the  one  solid,  the 
other  liquid ;  like  it,  too,  it  contains  all  the  elements  requisite  for 
nourishment  and  development,  it  serving  for  both  during  a  very  long 
period  of  the  life  of  the  human  species. 


196  ORGANIZED     FLUIDS. 


THE    SERUM    OF    THE    MILK. 


The  separation  of  the  serum  and  the  globules,  accomplished  in  an 
imperfect  manner  naturally,  is  more  completely  effected  artificially 
by  filtration;  the  serum,  by  means  of  the  ordinary  filtering  paper, 
may  be  obtained  transparent  and  colourless,  almost  free  from  globules, 
these  being  for  the  most  part  retained  upon  the  filter. 

It  may,  however,  be  observed,  that  the  first  portions  of  serum 
which  pass  through  the  paper  will  be  more  or  less  coloured  in  conse- 
quence of  their  containing  a  certain  number  of  the  smaller  globules, 
which  had  escaped  through  the  interstices  of  the  paper;  these 
coloured  and  semi-opaque  portions  of  serum  should  be  rejected. 

The  serum  contains  dissolved  in  it  the  sugar,  and  the  principal 
portion  of  the  cheese  of  milk,  as  well  as  certain  salts,  the  principal 
of  which  are  pointed  out  in  the  analysis  of  Haidlen. 

The  cheese  or  caseine  is  an  animal  principle,  which  in  its  proper- 
ties approaches  closely  fibrin:  it  is  precipitated  by  the  mineral,  the 
acetic,  and  the  lactic  acids. 

Although  the  greater  portion  of  the  caseine  exists  in  the  milk  in  a 
fluid  condition,  M.  Quevenne  appears  to  have  established  the  fact, 
that  it  is  also  present  in  a  solid  state  in  the  form  of  globules,  these 
being  exceedingly  small,  and  refracting  but  slightly  the  light;  the 
same  globules  may  also  be  detected  in  recently  precipitated  cheese. 
(See  Plate  XV.  fig.  5.) 

M.  Donne  has  shown  that  these  cheese  globules  may  be  demon- 
strated by  the  process  of  filtration;  thus,  the  first  few  drops  of  the 
milk  of  the  cow,  the  ass,  or  the  goat,  which  pass  through  the  filter, 
and  which  are  generally  white  and  opaque,  being  rejected,  and  the 
second  portion  of  filtered  milk  being  preserved,  and  allowed  to  remain 
undisturbed  for  a  few  minutes,  it  will  be  seen  to  separate  into  two 
parts,  the  inferior  of  which  is  clear  and  transparent,  while  the 
superior  is  somewhat  opaque.  Now,  if  a  drop  of  the  fluid  of  this 
inferior  layer  be  examined  with  the  microscope,  it  will  be  found  to 
contain  an  innumerable  quantity  of  globules  of  exceeding  minuteness, 
and  refracting  the  light  but  feebly,  as  well  as  occasionally  other 
globules  more  rare,  larger,  and  refracting  the  light  very  strongly;  the 
former  are  the  cheese  globules,  and  the  latter  the  proper  milk  globules. 


MILK.  197 


THE    GLOBULES. 


It  is  to  the  presence  of  the  globles  which  occur  in  such  vast  quan- 
tities in  each  drop  of  healthy  milk  that  the  colour  and  opacity  of  that 
fluid  is  due.*' 

These  globules  are  of  perfect  rotundity,  their  surface  being  smooth, 
presenting  a  pearly  aspect,  and  refracting  the  light  strongly;  the  cir- 
cumference of  each  globule  is  dark  and  the  centre  light :  the  globules 
vary  greatly  in  size;  the  smallest,  which  are  in  active  molecular 
movement,  being  reduced  to  mere  points,  and  not  exceeding  the 
t  8-7oo  of  an  inch,  the  largest  frequently  attaining  the  20V0  of  an  inch, 
and  the  medium  size  ranging  between  the  4  oV  0  of  an  inch  in  diameter 
and  the  45V  o-  (See  Plate  XIV.  fig.  1.)  In  milk  which  is  healthy, 
the  globules  float  freely  in  the  serum,  and  do  not  adhere  to  each  other. 

Such  is  the  form,  appearance,  and  variety  of  size  exhibited  by  the 
milk  globule;  much  difference  of  opinion  has  existed  in  reference 
to  its  organization,  some  observers  conceding  to  it  a  very  complex 
structure,  others  denying  it  even  the  most  simple  organization. 

Some  of  the  more  remarkable  of  the  opinions  entertained  by  the 
more  noted  investigators  may  here  be  referred  to. 

According  to  Turpin,  "the  structure  of  the  milk  globule  consists 
of  two  spherical  vesicles,  fitting  the  one  into  the  other,  and  enclosing 
in  their  interior  very  fine  globules  and  buttery  oil."f 

Mandl  says,  "  the  globules  of  milk  ought  then  to  be  considered  as 
organized  corpuscles,  composed  of  a  membrane  probably  formed  of 
cheese,  and  of  contents  which  constitute  the  butter."  J 

Henle  writes,  the  globules  of  milk  "are  not  simple  molecules  of 
grease,  and  have  an  independent  membrane  surrounding  them  ;"§ 
this  he  elsewhere  states  to  be  probably  composed  of  caseine,  in  which 
respect  there  is  an  agreement  of  opinion  between  Henle  and  Mandl. 

The  complex  structure  ascribed  to  the  milk  globule  by  Turpin  it  is 
altogether  impossible  to  demonstrate ;  and  the  experiments  and  obser- 
vations which  have  hitherto  been  made  in  reference  to  its  constitution 

*  Leeuwenhoek  first  clearly  indicated  the  existence  of  these  globules  in  the  milk 
in  the  following  terms:  "  Vidi  multos  globulos,  similes  sextas  parti  globuli  sanguinei; 
et  etiam  alios,  quorum  bini  terni  aut  quaterni  se  invicem  modo  attingebant,  fundum 
versus  descendere;  et  multos  varies  magnitudinis  globulos  in  superficie  fluitantes, 
inter  quos  posteriores  adipem  sive  butyrum  esse  judicabam." 

f  Annates  des  Sciences  Naturelles.  j  Anat.  Micros,  p.  53. 

§  Anat.  Gen.  t.  vii.  p.  522. 


198  ORGANIZED     FLUIDS. 

are  entirely  opposed  to  his  view,  which  may  safely,  therefore,  be  con- 
sidered to  be  incorrect. 

Mandl  founded  his  belief  of  the  existence  of  a  distinct  membrane 
enveloping  the  globules  mainly  on  the  following  observation:  He 
remarked  that  if  a  little  drop  of  milk  be  compressed  strongly  between 
two  plates  of  glass,  the  upper  plate  at  the  same  time  being  drawn 
over  the  surface  of  the  other  in  a  straight  line,  the  milk  globules  will 
be  broken  up  by  the  compression,  and  drawn  out  into  a  certain  form : 
if  a  magnifying-glass  be  applied  to  the  globules  thus  compressed,  they 
will  be  seen  to  present  the  appearance  of  long  pale  and  straight  lines, 
with  smaller  straight  lines  placed  usually  at  right  angles  to  the  larger 
ones.  "These  little  lines,"  he  says,  "are  nothing  else  than  the  curled 
membranes  of  the  globules,  the  contents  of  which,  the  butter,  consti- 
tuting the  long  streaks :  we  may  easily  convince  ourselves  of  this  by 
adding  a  little  water.  The  streaks  disappear,  and  we  see  in  their 
place  oleaginous  drops  of  different  forms,  while  the  little  membranes 
remain  either  attached  to  the  glass  or  indifferently  curved,  swimming 
in  the  serum.  These  membranes  are  insoluble  in  ether,  which  dis- 
solves the  drops." 

These  observations  of  Mandl,  presuming  for  a  moment  that  they 
are  accurate  in  every  particular,  are  yet  insufficient  to  prove  the 
existence  of  a  distinct  membrane  surrounding  the  globules,  although 
they  certainly  would  be  so,  if  correct,  to  establish  the  fact  that  they 
are  constituted  of  two  different  substances,  the  one  of  which  is  soluble 
in  ether  and  the  other  insoluble.  Had  iodine  been  employed,  and 
had  it  been  imbibed  by  the  supposed  membrane,  and  turned  of  a  deep 
brown,  the  reality  of  the  existence  of  the  membrane  in  question  might 
have  been  considered  as  demonstrated :  but  we  know  that  iodine  does 
not  affect  the  colour  of  the  milk  globule  in  the  least. 

I  am  far,  however,  from  attaching  the  smallest  importance  to  the 
experiment  of  Mandl,  because  I  conceive  that  he  has  misinterpreted 
the  appearances  which  he  noticed.  The  larger  streaks  are  not  con- 
stituted of  a  single  elongated  globule,  but  are  made  up  by  the  union 
of  several  milk  globules,  as  is  evident — first,  from  the  size  of  the 
streaks,  and,  second,  from  the  traces  which  they  bear  of  such  a  com- 
position in  themselves;  as,  for  example,  the  occurrence  of  contractions 
at  certain  intervals,  while  the  smaller  lines,  and  which  are  most 
generally  absent,  are  formed  usually  by  other  globules  of  less  size 
joining  at  an  angle  the  larger  streaks.  The  solubility  of  the  one  in 
ether  and  the  insolubility  of  the  other  in  that  reagent,  I  have  not  been 
able  to  observe. 


MILK.  199 

The  opinion  of  Henle,  that  the  milk  globule  is  furnished  with  an 
envelope,  rests  chiefly  upon  the  manner  in  which  acetic  acid  acts 
upon  it. 

Henle  thus  describes  the  effects  of  the  application  of  acetic  acid: 

"  Treated  by  dilute  acetic  acid,  the  globules  of  milk  undergo,  little 
by  little,  a  remarkable  change;  some  of  them  become  oval  or  take  the 
the  form  of  a  biscuit;  upon  others,  appear  gradually  on  one  or  many 
points  a  smaller  globule,  which  rests  upon  the  margin,  and  increases 
in  an  insensible  manner."  *•■*.*«  If  more  acetic  acid  be  added, 
the  milk  globules  appear,  as  it  were,  melted  down  with  smooth  but 
irregular  borders :  they  approach  the  one  to  the  other,  and  unite  into 
large  masses,  which  resemble  perfectly  melted  fat  which  has  run 
along  in  an  irregular  manner.  When  to  a  drop  of  milk  are  added 
two  drops  of  concentrated  acetic  acid,  and  the  mixture  then  placed 
under  the  microscope,  we  no  longer  perceive  any  regular  globule  of 
milk,  or,  at  least,  we  discover  but  very  few:  the  most  are  reduced 
into  one  or  several  irregular  particles,  which,  with  the  naked  eye, 
may  be  distinguished  upon  the  surface  of  the  drop,  which  otherwise 
has  become  clear.  The  same  changes  are  produced  in  the  space  of 
a  few  days,  when  the  milk,  abandoned  to  itself,  becomes  acid  by  the 
metamorphosis  of  its  sugar."* 

These  ingenious  observations  of  Henle,  like  those  of  Mandl,  are 
yet  insufficient  to  demonstrate  the  existence  of  a  distinct  and  organ- 
ized membrane  surrounding  the  milk  globule,  although  they  would  be 
assuredly  so,  if  correct,  to  render  it  quite  certain  that  it  is  enveloped 
with  a  coating  of  a  material  very  distinct  from  fat,  and  probably  of 
the  nature  suggested  by  Mandl  and  Henle 

Here,  again,  however,  it  becomes  a  question  whether  the  appear- 
ances noticed  by  Henle  have  not  been  misinterpreted,  and  whether 
the  internal  buttery  substance  does  really  protrude  through  apertures 
in  the  envelope  of  the  globule  occasioned  by  the  action  of  acetic  acid: 
in  the  first  place,  it  seems  to  me  that  the  milk  globules  are  too  small  to 
allow  of  the  determination  of  the  point  in  question  with  any  degree 
of  certainty ;  and,  secondly,  that  in  those  instances  in  which  observers 
might  fancy  that  an  escape  of  the  included  substance  of  the  globule 
through  its  envelope  had  really  occurred,  such  an  appearance  is,  in 
all  probability,  due  to  the  adhesion  together  and  partial  fusion  of  two 
or  more  globules.     (See  Plate  XV.  fig.  4.) 

*  Henle,  Anat.  Gen.  p.  521,  522. 


200 


ORGANIZED     FLUIDS 


There  are  other  observers  again — as  Wagner,  Nasse,  arid 
QueVenne — who  would  deny  to  the  milk  globule  all  organization,  and 
who  regard  it  as  of  a  perfectly  homogeneous  nature. 

The  truth  in  this  instance,  as  in  so  many  others,  would  appear  to 
lie  in  the  mean.  That  the  milk  globule  is  not  provided  with  a 
distinct  and  separate  membrane,  similar  to  that  of  the  mucous 
corpuscle,  is  proved  by  the  impossibility  of  demonstrating  the  existence 
of  any  such  structure,  as  well  as  by  the  absence  of  a  double  line 
around  its  margin,  the  non-effect  of  iodine,  and  the  coalition  of  the 
globules  resulting  from  pressure,  first  observed  by  Dujardin. 

That  it  is  not  constituted  of  a  single  perfectly  homogeneous 
substance,  is  also  demonstrated  by  the  observations  of  Mandl  and 
Henle,  and  especially  by  those  of  the  latter  observer  on  the  effects 
produced  by  acetic  acid. 

That  the  milk  globule  is  not  wholly  composed  of  fatty  matter,  is 
shown  by  its  insolubility  in  boiling  water  raised  to  a  very  high  tempera- 
ture, in  boiling  alcohol,  in  the  alkalies,  and  by  the  effects  of  the 
application  of  acetic  acid.  Ether  dissolves  the  milk  globules :  their 
solution,  however,  it  does  not  entirely  accomplish  on  its  first  applica- 
tion, although  the  ether,  the  moment  it  comes  in  contact  with  the 
globules,  causes  them  to  lose  their  rotundity,  to  fall  down,  and  to  run 
together  into  masses  of  various  sizes,  but  most  of  which  still  present 
a  circular  outline. 

If  a  drop  of  milk  be  examined  microscopically,  after  its  treatment 
by  ether,  a  hasty  observer  might  conclude,  from  noticing  so  many  of 
the  circular  masses  alluded  to,  that  the  reagent  had  not  exerted  any 
influence  on  the  milk  globules,  and  that  these  masses  were  the 
unaltered  globules.  This  view,  however,  a  little  reflection  would 
soon  show  to  be  incorrect;  for  many  of  the  circular  bodies  now 
noticed  on  the  field  of  the  microscope  are  larger  than  even  the  largest 
milk  globules,  and  all  of  them  are  flat  and  semi-fluid.  (See  Plate 
XV.  fig.  3.) 

The  several  facts  now  adduced,  while  they  prove  that  the  milk 
globule  is  not  organized  in  accordance  with  the  interpretation  of  the 
.word  organization  usually  given,  yet  seem  sufficient  to  establish  the 
fact  that  it  is  composed  of  two  distinct  organic  products — the  one 
internal  and  fatty,  and  the  other  external,  and  possessed  of  properties 
distinct  from  fat. 

This  explanation  of  the  constitution  of  the  milk  globule  serves  to 
explain  also  satisfactorily  the  facts   above  alluded   to,  viz:  the  non- 


MILK.  201 

action  of  boiling  water,  alcohol,  and  alkalies,  all  of  which  affect  more 
or  less  fat,  as  also  the  slower  operation  of  the  ether:  it  also  shows 
why  boiling  alcohol  should  immediately  dissolve  the  milk  globules, 
to  which  a  little  acetic  acid  had  been  previously  added,  this  latter 
reagent  first  removing  their  outer  coating,  which  is  insoluble  in  alcohol. 

Between  the  globules  of  the  previously-described  fluids — those  of 
the  lymph  and  chyle,  of  the  blood,  mucus  and  pus,  and  globules  of 
milk — no  structural  or  functional  relation  whatever  exists ;  the  former 
being  complex  and  definite  organizations  or  cells,  and  the  latter 
constituted  of  two  distinct  substances  indeed,  yet  want  entirely  the 
attributes  of  cells,  being  destitute  of  nucleus  and  cell  wall. 

It  is  of  the  globules  just  described  that  the  cream  is  constituted, 
their  accumulation  on  the  surface  of  the  milk  being  due  to  their 
lighter  specific  gravity;  it  is  also  by  their  incorporation  with  each 
other,  and  which  is  effected  by  the  operation  of  churning,  that  butter 
is  formed. 

COLOSTRUM. 

The  milk  which  is  secreted  the  first  few  days  after  child-birth  has 
been  denominated  colostrum :  it  differs  very  considerably  from 
ordinary  milk,  being  of  a  yellow  colour,  of  a  viscous  consistence, 
and  containing  a  very  large  proportion  of  milk  globules,  which  give 
rise  to  the  formation  upon  it  of  a  thick  layer  of  cream;  when  treated 
with  ammonia,  it  becomes  glairy  and  tenacious. 

Corresponding  with  the  outward  characters  of  the  colostrum,  there 
are  others  indicated  by  the  microscope  not  less  remarkable :  thus,  the 
larger  true  milk  globules  which  occur  in  it  are  but  ill-defined,  being 
irregular  in  form  and  size,  appearing  as  though  they  were  but  imper- 
fectly elaborated,  and  presenting  rather  the  aspect  of  oil  globules, 
while  the  smaller  ones  are  like  a  fine  powder  strewn  through  the 
serum,  and  adhering  to  the  surface  of  the  larger  globules,  which  also, 
in  place  of  floating  freely  and  separately  in  the  serum,  are  agglomer- 
ated together  as  if  held  in  union  by  some  viscous  material.  (See 
Plate  XIV.  figs.  4  and  5.) 

But  besides  the  state  of  the  ordinary  milk  globules  just  described, 
there  are  found  in  the  colostrum  peculiar  corpuscles  of  a  totally 
distinct  structure :  these  were  first  discovered  and  described  by  M. 
Donne,  who  has  denominated  them  "  Corps  granuleux." 

These  corpuscles  are  mostly  several  times  larger  than  the  milk 
globules,   are  less  regular  in   form,   although  usually  more  or  less 


202  ORGANIZED     FLUIDS. 

spherical  in  outline,  and  present  a  uniformly  molecular  aspect  and  a 
yellow  coloration;  the  edges  of  the  corpuscles  sometimes  appear 
smooth,  as  if  possessed  of  an  envelope ;  at  others,  their  margins  are 
rough,  and  convey  the  impression  that  they  are  destitute  of  any 
external  covering.  See  Plate  XIV.  figs.  3  and  4.)  Occasionally  one 
or  more  milk  or  oil  globules  are  imprisoned  in  the  substance  of  the 
corpuscles,  which  then  occupy  the  position,  although  they  do  not 
discharge  the  office,  of  a  nucleus. 

Some  difference  of  opinion  is  entertained  respecting  their  intimate 
structure:  Gueterboch,  and  probably  Donne,*  conceive  that  they  are 
furnished  with  an  investing  membrane,  and  therefore  that  they  are 
veritable  cells,  while  Henlef  regards  them  as  masses  or  aggregations 
of  granules  agglomerated  together  in  an  amorphous  and  mucoid 
substance ;  an  opinion  in  which  I  concur. 

Donne  states  that  the  colostrum  corpuscles  are  soluble  in  ether,  and 
therefore  that  they  are  of  a  fatty  nature :  the  fact  of  their  solubility, 
however,  seems  to  me  to  be  difficult  to  verify ;  and  from  observations 
which  I  have  made,  I  cannot  help  thinking  that  this  point  is  scarcely 
as  yet  established.  Certain  it  is  that  corpuscles  larger  than  mucous 
globules,  and  in  every  way  similar  to  the  colostrum  corpuscles,  save 
that  traces  of  nuclei  may  be  detected  in  them,  appear  in  colostrum 
treated  with  ether. 

The  "  Corps  granuleux  "  are  insoluble  in  the  alkalies,  J  are  coloured 
brown  by  iodine,  and  the  substance  which  unites  the  granules  is 
dissolved  by  acetic  acid.§ 

The  state  of  the  milk  just  described  does  not  continue  without 
alteration,  each  condition  which  has  been  alluded  to  undergoing  a 
daily  modification :  thus  the  milk  globules  from  day  to  day  acquire 
greater  uniformity  of  size  and  shape,  they  no  longer  adhere  together, 
but  float  freely  and  singly  in  the  serum,  which  does  not  become  viscid 
on  the  addition  of  ammonia,  the  smaller  dust-like  globules  also 
altogether  disappearing ;  at  the  same  time  the  number  of  the  colostrum 
corpuscles  diminishes  until  at  length  none  exist.  (See  Plate 
XIV.  fig.  1.) 

These  several  changes  are  all  accomplished  in  the  course  of  a  few 
days,  so  that  by  the  end  of  the  twenty-fourth  day,  the  milk  has 
usually  entirely  passed  from  the  condition  of  colostrum,  and  presents 
only  its  ordinary  characters.     The   colostrum,   however,  does  not 

*  Cours  de  Microscopie,  p.  401.  f  Anal.  Gen.  t.  vii.  p.  525. 

J  Donne,  loc.  cit.  p.  401.  JHenle,  loc.  cit.  t.  vii.  p.  525. 


MILK.  203 

always  pass  through  its  various  modifications  in  the  time  specified ;  it 
may  do  so  in  either  a  shorter  or  a  longer  period  than  that  stated: 
thus,  the  existence  of  the  milk  in  the  form  of  colostrum  can  scarcely 
be  regarded  as  affording  any  very  certain  test  whereby  the  age  of 
the  milk  may  be  determined. 

The  colostrum  corpuscles  would  appear  to  be  almost  peculiar  to 
the  human  subject,  for  while  their  presence  in  the  milk  of  woman  is 
almost  constant,  their  occurrence  in  that  of  animals — as  the  cow,  the 
ass,  and  the  goat — i%rare  and  exceptional. 

Professor  Nasse  states  that  they  disappear  sooner  in  women  who  have 
borne  many  children  than  in  those  who  have  had  but  a  single  child. 

Mucous  corpuscles  are  also  occasionally  encountered  in  the  colos- 
trum. They  are,  however,  neither  very  generally  present,  nor  do 
they  occur  in  any  very  great  numbers. 

The  colostrum,  or  first  milk,  is  possessed  of  purgative  qualities. 

PATHOLOGICAL    ALTERATIONS    OF    THE    MILK. 

Persistence  of  this  Fluid  in  the  condition  of  Colostrum. 

It  has  been  stated,  that  usually  by  the  end  of  the  twenty-fourth 
day  after  child-birth,  and  frequently  at  a  much  earlier  period,  the 
colostrum  has  lost  all  its  distinctive  characters,  and  the  milk  has 
arrived  at  its  perfect  condition. 

This  transformation  of  the  colostrum  into  fully- elaborated  milk,  it 
has  been  observed,  is  not  always  effected  in  the  time  named :  it  may 
be  accomplished  in  either  a  shorter  or  a  longer  period ;  thus,  the  milk 
in  some  cases  loses  the  chief  characters  of  colostrum  in  as  short  a 
space  of  time  as  three  or  four  days,  while  in  others  it  retains  them  for 
months  after  the  birth  of  the  child,  and  even  until  the  end  of  lactation. 

This  persistence  of  the  milk  in  the  state  of  colostrum  may  be 
present  without  any  suspicion  of  its  existence  being  entertained,  the 
milk  exhibiting  its  ordinary  outward  appearances. 

It  is,  therefore,  only  by  means  of  the  microscope  that  its  true 
condition  can  be  ascertained.  Examined  with  this  instrument,  the 
characteristics  of  colostrum  will  be  detected ;  thus,  the  globules  which 
do  not  float  freely  in  the  serum,  and  which  are  large  and  ill-formed, 
will  be  seen  to  adhere  together  in  groups,  as  though  held  in  union  by 
some  viscous  substance,  and  intermixed  with  them  will  be  noticed 
numerous  colostrum  corpuscles. 

It  cannot  be  doubted  but  that  such  persistence  of  the  milk  in  the 
form  vi  colostrum  exerts  a  most  injurious  effect  upon  the  child :  the 


204  ORGANIZED     FLUIDS. 

colostrum  is,  as  we  know,  possessed  of  purgative  properties;  these, 
during  the  first  days  of  the  life  of  the  infant,  are  necessary;  their 
continuance  cannot  but  impair  its  strength  and  health. 

Recurrence  of  Colostrum. 

M.  Donne  has  established  the  interesting  fact  that  milk  which  has 
entirely  lost  the  character  of  colostrum,  and  which  has  reached  its 
perfect  maturity,  may  again  pass  into  the  state^of  colostrum  at  any 
period  during  the  course  of  lactation. 

Thus,  the  milk  which  had  at  one  time  presented  the  constitution  of 
perfectly  formed  milk  has  been  seen  by  M.  Donne  to  acquire  gradually 
that  which  is  indicative  of  the  colostrum,  it  becoming  viscous,  and 
the  globules  contained  in  it,  instead  of  floating  freely  and  singly  in 
the  serum,  uniting  with  each  other,  forming  irregular  masses,  the 
granular  and  mucous  corpuscles  at  the  same  time  being  present  in  it 
in  considerable  quantities. 

In  the  instances  in  which  the  recurrence  has  been  observed, 
engorgement  of  one  or  both  of  the  mamary  glands  has  usually 
preceded  it. 

When  but  one  gland  is  affected,  the  milk  of  that  gland  only  presents 
the  characters  of  colostrum,  that  of  the  opposite  side  retaining  its 
usual  properties  and  constitution. 

The  recurrence  of  the  colostrum  would  appear  to  depend,  as  a 
cause,  either  upon  lesion  of  the  mammary  gland,  or  upon  a  deranged 
or  vitiated  condition  of  the  health. 

Influence  of  prolonged  Retention  of  the  Milk  on  its  Constitution. 

M.  Peligot  has  made  the  observation,  important  in  a  practical  point 
of  view,  that  the  milk  which  has  been  allowed  to  remain  for  a  long 
time  in  the  breast  becomes  thin  and  watery,  an  effect  which  is 
contrary  to  that  which  occurs  in  reference  to  most  other  secretions 
of  the  economy,  the  urine  and  the  bile,  the  density  of  which  is 
heightened  by  retention. 

Thus,  if  the  milk  abstracted  at  one  time,  and  which  has  been  long 
secreted,  be  divided  into  three  parts,  each  being  received  successively 
into  a  distinct  vessel,  the  first  milk  will  seem  to  be  poor  and  watery, 
the  second  more  rich,  and  the  third  the  most  so  of  the  entire.  The 
first  portion  is  to  be  regarded  as  that  which  has  been  longest  formed, 
and  the  third  as  the  most  recently  secreted. 


MILK.  205 

The  knowledge  of  the  above  fact  leads  to  one  practical  result  in 
the  case  in  which  the  milk  is  too  rich  for  the  digestive  powers  of  the 
child  ;  thus  by  allowing  such  milk  to  remain  for  a  longer  period  than 
usual  in  the  breast,  a  fluid  of  lighter  quality  and  less  abounding  with 
nutritive  principles  will  be  obtained. 

A  second  effect  of  prolonged  retention  or  engorgement  of  the  milk 
in  the  breast  is  to  occasion  the  aggregation  of  the  globules  into 
masses.     (See  Plate  XIV.  fig.  6.) 

Pus  and  Blood  in  the  Milk. 

Having  now  described  those  constituents  by  the  combination  of 
which  milk  is  formed,  as  well  as  the  several  conditions  in  which 
these  may  be  encountered,  we  may  next  refer  to  those  structures 
which  occasionally  occur  in  milk  as  the  result  of  disease. 

Thus,  the  corpuscles  of  both  pus  and  the  blood  are  sometimes 
encountered  in  the  milk,  those  of  the  former  fluid  occurring  much 
more  frequently  than  those  of  the  latter. 

The  puriform  matter  which  issues  from  the  breast  in  cases  of 
abscess  of  that  gland  is  made  up  of  a  mixture  of  pus  and  milk  glo- 
bules, with  occasionally  blood  discs.     (See  Plate  XV.  fig.  1.) 

But  both  pus  and  blood  corpuscles*  the  latter  very  rarely,  may  be 
contained  in  the  milk  which  issues  from  the  breast  through  its  natural 
channels. 

I  was  so  fortunate  as  to  meet  with  an  excellent  example  of  blood 
in  the  milk,  the  occurrence  of  which  is  so  rare  that  Donne,  at  the 
period  of  the  publication  of  the  "  Cours  de  Microscopie,"  and  with 
all  his  researches  on  the  milk,  had  never  encountered  a  single  instance 
of  such  pathological  alteration  in  the  human  subject.  The  case  in 
which  this  occurred  was  that  of  a  young  woman  confined  of  her  first 
child ;  the  milk  not  appearing  at  the  usual  time,  the  friends  became 
anxious,  and  one  of  them,  more  officious  and  more  ignorant  than  the 
rest,  had  the  nipples  drawn  with  such  vigour  and  effect  as  to  cause 
the  extraction  of  a  liquid  half  blood  and  half  milk.  (Plate  XV.  fig.  2.) 
The  occurrence  of  blood  corpuscles  in  the  milk  can  only  take  place 
as  the  consequence  of  a  rupture  of  some  of  the  smaller  blood  vessels 
which  are  distributed  through  the  mammary  gland. 

The  above  facts  clearly  show  the  impropriety  of  applying  an  infant 
to  the  breast  in  cases  of  inflammation  and  suppuration  in  that  organ. 

Not  the  least  difficulty  need  be  experienced  in  the  detection  of  pus 
and  blood  corpuscles  in  the  milk,  their  form  and  structure  being  so 


206  ORGANIZED     FLUIDS. 

totally  dissimilar  to  those  of  the  proper  milk  globules.  Reagents 
also  affect  the  different  kinds  of  corpuscles  differently.  Thus,  the 
milk  globules  are  soluble  in  ether,  which  does  not  materially  affect 
the  pus  and  blood  corpuscles,  the  latter  of  which  is  dissolved  by 
acetic  acid,  and  the  former  only  by  the  caustic  alkalies. 

The  Milk  of  Syphilitic  Women. 

M.  Donne  has  made  repeated  attempts  to  discover  in  the  milk  of 
women  labouring  under  syphilis,  in  different  forms,  some  element 
which  would  account  for  the  transmission  of  the  affection  from  the 
mother  to  the  infant.  These  endeavours  were,  however,  entirely 
fruitless ;  nor  is  this  result  other  than  what  might  have  been  antici- 
pated, for  it  is  scarcely  to  be  supposed  that  the  venereal  virus  exists 
any  where  in  a  tangible  form ;  and  if  it  really  does  so,  it  would  still 
be  a  matter  of  impossibility  to  point  out  the  channels  by  which  any 
solid  matter  could  make  its  way  through  the  system  and  mingle  with 
the  secretion  of  the  mammary  gland. 

The  Milk  of  Women  in  the  Case  of  the  premature  Return  of  their 

Natural  Epochs. 

The  milk  of  women  in  whom  the  natural  periods  have  returned 
during  the  course  of  lactation,  has  likewise  been  carefully  examined. 
Except  in  a  single  instance,  however,  it  has  not  been  found  to  present 
any  thing  remarkable  in  its  characters.  In  the  case  referred  to,  it 
had  degenerated  to  the  condition  of  colostrum,  and  contained  the 
granular  colostrum  corpuscles. 

THE    MILK    OF   UNMARRIED    WOMEN. 

The  breasts  of  many  women  who  have  not  been  married  are  fre- 
quently found  to  contain  an  abundance  of  milk,  and  from  those  of 
most,  more  or  less  of  a  milky  fluid  can  be  obtained. 

This  milk  exhibits  all  the  characters  of  colostrum,  containing  even 
the  peculiar  corpuscles  which  distinguish  that  condition  of  the  milk ; 
it  is  therefore,  like  the  first  milk,  to  be  regarded  as  an  imperfectly 
elaborated  substance. 

THE    MILK    OF    WOMEN   PREVIOUS    TO    CONFINEMENT. 

The  breasts  of  most  women  during  the  last  few  weeks  of  gestation 
contain  more  or  less  milk,  which  also  presents  all  the  characters  of 
colostrum. 


MILK.  207 

The  quantity  of  milk  contained  varies  greatly;  in  some  cases  a 
few  drops  of  a  milk-like  fluid  only  can  be  obtained ;  in  others  it  is 
more  abundant ;  and  again,  in  other  instances,  it  is  still  more  plentiful, 
and  rich  in  quality. 

The  question  may  be  asked,  does  there  exist  any  relation  between 
the  quantity  and  condition  of  the  milk  before  confinement,  and  its 
state  when  it  has  arrived  at  perfection  after  this  event  has  occurred  ? 
In  other  terms,  can  one  pronounce,  by  the  milk  in  the  breasts,  before- 
hand, whether  a  woman  will  have  a  sufficient  quantity  of  milk  to 
nourish  her  infant  ? 

This  question,  which  so  often  presents  itself  to  the  consideration 
of  the  medical  practitioner,  M.  Donne  has  discussed  at  some  length, 
and  to  it  he  replies  thus : 

"  The  secretion  of  the  mammary  gland,"  he  says,  "  is  after  con- 
finement in  constant  relation  with  the  state  which  it  presents  during 
gestation,  so  that  it  is  possible  to  know  in  advance,  by  the  observation 
of  its  characters  during  the  last  months  of  pregnancy,  what  its 
condition  will  be  when  it  shall  have  acquired  all  its  activity  after 
parturition."*  This  law,  he  states,  is  so  general,  that  in  the  sixty 
observations  which  he  has  made  on  women  of  all  ages  and  tempera- 
ments, he  has  met  with  but  two  or  three  exceptions. 

Pregnant  women  Donne  divides  into  three  classes,  founded  upon 
the  characters  presented  by  the  colostrum  during  the  last  months  of 
gestation : 

1st.  Those  in  whom  the  secretion  is  small,  and  the  viscous  liquid 
contains  scarcely  any  milk  globules,  mixed  with  a  very  few  colostrum 
corpuscles. 

2d.  Those  in  whom  the  colostrum  is  more  or  less  abundant,  but 
poor  in  milk  globules,  which  are  small,  ill-formed,  and  containing 
also  colostrum  and  mucous  corpuscles. 

3d.  Those  in  whom  the  colostrum  is  very  abundant,  rich  in  milk 
globules,  which  are  of  good  size,  and  unmixed  with  any  other  cor- 
puscles save  those  proper  to  the  colostrum. 

Now,  the  indications  to  be  deduced  from  the  different  states  of  the 
colostrum  just  described  are — 

That  the  first  state  appertains  to  women  in  whom  the  secretion  of 
milk  after  child-birth  is  either  very  little,  or  in  whom  there  is  pro- 
duced but  a  serous  milk,  poor  in  nutritive  elements,  and  therefore 
insufficient  for  the  nourishment  of  the  child. 

*  Cours  de  Microscopk,  p.  406. 


208  ORGANIZED     FLUIDS. 

That  the  second  condition  indicates  those  in  whom  tne  secretion 
of  milk  after  confinement  is  either  small  or  abundant  in  quantity,  but 
which  is  always  poor  and  serous. 

That  the  third  state  of  the  colostrum  belongs  only  to  such  women 
as  have  an  abundant  supply  of  milk  of  good  quality. 

THE    MILK    OF    WOMEN    WHO    HAVE    BEEN    DELIVERED,    BUT    WHO    HAVE    NOT    NURSED 

THEIR    OFFSPRING. 

The  mammary  gland  of  women  who  have  borne  children,  but  who 
have  not  nursed  them,  is  frequently  found  to  contain  milk  many 
months  after  confinement. 

This  milk  always  presents  the  characters  of  colostrum. 

MILK    IN    THE    BREASTS    OF    CHILDREN. 

A  milk-like  fluid  can  frequently  be  expressed  from  the  breasts  of 
infants  and  young  children,  both  male  and  female. 

This  fluid,  examined  microscopically,  has  been  found  to  exhibit  all 
the  characters  of  ordinary  milk;  and,  in  some  cases,  the  colostrum 
corpuscles  have  even  been  detected  in  it. 

DIFFERENT    KINDS    OF    MILK. 

The  milk  of  one  mammiferous  animal  resembles  so  closely  that  of 
another  that  it  is  often  a  matter  of  impossibility  to  distinguish,  either 
with  the  naked  eye  or  by  means  of  the  microscope,  the  different  kinds 
of  milk. 

The  milk  of  the  ass  may,  however,  be  generally  known  by  its 
watery  aspect,  its  bluish  tint,  and  its  lightness;  that  of  woman  by  the 
promptitude  with  which  the  layer  of  cream  is  formed  upon  it;  but  it 
is,  above  all,  by  the  taste  that  the  several  kinds  of  milk  are  charac- 
terized :  thus,  the  taste  of  the  milk  of  the  cow  can  scarcely  be  con- 
founded with  that  of  the  ass  or  goat,  nor  can  the  flavour  of  the  milk 
of  woman  be  mistaken  for  that  of  any  of  these. 

The  microscope  aids  but  little  in  the  discrimination  of  the  different 
kinds  of  milk:  the  globules  of  the  milk  of  the  goat  are  certainly 
smaller  than  those  of  the  other  species  named,  and  those  of  the  ass 
are  less  numerous;  nevertheless,  these  characters  are  so  little  con- 
stant that  they  are  not,  in  many  instances,  sufficient  to  distinguish 
them  from  the  milk  of  the  cow  or  of  woman. 

The  number  of  globules  contained  in  the  milk  of  different  animals 
doubtless  varies  considerably;  but  there  is  as  much  variation  in  this 


MILK 


209 


respect  as  in  those  just  referred  to;  and,  therefore,  this  difference  is 
not  sufficient  to  distinguish  the  several  kinds  of  milk. 

RELATIVE    PROPORTIONS    OF    THE    ELEMENTS    OF    MILK. 

Chemical  analysis  indicates  a  very  great  variety  in  the  relative 
proportions  of  the  different  nutritive  ingredients  of  milk;  and  this,  not 
merely  with  respect  to  the  milk  of  different  animals,,  but  also  in  refer- 
ence to  that  of  the  same  species,  and  even  of  the  same  individual,  at 
different  times. 

The  truth  of  these  remarks  will  be  evident  from  an  examination  of 
the  following  analyses : 

Analysis  of  the  Milk  of  Woman,  by  Peyen. 
Butter,  -  -  -  -  5-16 

Sugar  and  cream,  -  -  -  7 '  80 


Analysis  of  the  same,  by  F.  Simon. 
Water,  .... 

Caseine,  .... 

Sugar,  .... 

Butter,  —  - 

Salts,  extractive  matter,  &c, 


88 

06 

3 

•70 

4 

54 

3 

40 

0 

30 

100 

00 

Analysis  of  the  Milk  of  Woman,  the  Cow,  the  Goat,  and  the  Ass,  by  Meggenhofen, 
Van-Stiptrian,  Liuscius,  and  Bonpt,  and  Peligot.* 


Woman. 

Cow. 

Goat. 

Ass. 

Butter, 

8-97 

2-68 

456 

1-29 

Sugar, 

120 

5  68 

9   12 

6-29 

Caseine, 

1-93 

895 

4-38 

1-95 

Water, 

87-90 

84'69 

81-94 

90-95 

It  will  be  seen  from  the  above  analyses  that  the  milk  of  woman  is 
the  richest  in  butter,  while  that  of  the  ass  contains  the  smallest 
amount  of  that  element. 

The  assertion  made  by  Donn&,  that  the  quantity  of  butter  in  the 
milk  of  the  same  species  stands  in  relation  with  that  of  the  other 
essential  ingredients  of  the  milk,  although  supported  by  the  researches 
of  Peyen  and  Peligot,  is  contradicted  by  those  of  F.  Simon.     Accord- 

*  This  analysis  is  copied  from  the  Cours  de  Microscopie  of  Donne. 
14 


210  ORGANIZED     FLUIDS. 

ing  to  the  analyses  of  Simon,  the  quantity  of  sugar  is  greatest  imme- 
diately after  delivery;  a  few  days  being  passed,  this  diminishes,  and 
the  amount  of  caseine,  which  was  at  first  very  small,  undergoes  a 
gradual  augmentation.  The  butter  Simon  considers  to  be  the  most 
variable  element  of  the  milk,  its  variations  not  being  reducible  to 
any  law. 

The  relative  proportion  of  the  different  ingredients  of  the  milk  of 
animals  may  be  modified,  and  almost  altered,  at  will,  by  the  adoption 
of  a  certain  regimen. 

GOOD     MTT.V. 

The  purity  and  the  richness  of  milk  were  formerly  estimated  by  its 
specific  gravity,  which  is  about  1  '032;  if  the  milk  was  poor  in  cream, 
or  if  it  was  diluted  with  water,  it  was  supposed  that  the  gravity  of  the 
fluid  would  be  in  the  first  case  increased,  and  in  the  second  lessened. 

The  cream  being  the  lightest  element  of  the  milk,  its  deficiency  or 
its  abstraction  would,  of  course,  increase  the  density  of  the  remaining 
fluid,  and  the  addition  of  water,  after  the  removal  of  the  cream,  which 
is  also  of  less  weight  than  milk  which  is  even  pure  and  rich,  would, 
of  course,  raise  the  gravity  of  the  milk  either  up  to  or  even  beyond 
its  natural  weight. 

Now,  the  abstraction  of  the  globular  element  of  the  milk  and  the 
addition  of  water  are  the  two  frauds  most  frequently  had  recourse  to; 
and  they  are  of  such  a  nature  as  to  elude  detection  by  reference  to 
the  specific  gravity  of  the  milk,  when  they  are  both  put  in  practice 
in  combination. 

The  specific  gravity  test  of  the  purity  and  richness  of  milk  is,  then, 
one  which  is  fallacious,  and  therefore  but  of  very  little  value. 

It  has  been  proposed  by  M.  Quevenne,  not  merely  to  estimate  the 
specific  gravity  of  milk,  but  also  to  measure  the  layer  of  cream  which 
forms  upon  it  by  repose.  This  ingenious  method  is  scarcely  more  to 
be  depended  upon  than  the  preceding,  and  is  put  at  fault  by  the  fact 
that  the  addition  of  water  favours  the  ascension  of  the  cream. 

Thus,  the  layer  of  cream  formed  on  milk  to  which  water  has  been 
added  will  be  thicker  than  that  of  unadulterated  milk,  this  effect  being 
the  consequence  of  the  lessened  specific  gravity  resulting  from  the 
addition  of  the  water. 

Donne  has  made  the  statement,  which  is  borne  out  by  the  analyses 
of  MM.  Peyen  and  Peligot,  that  the  globular  or  buttery  element  of 
the  milk  stands  in  relation,  in  the  milk  of  the  same  species  of  animal, 


MILK.  211 

though  not  in  different  species,  with  the  other  nutritive  ingredients  of 
milk,  the  cheese  and  the  sugar.  The  analyses  referred  to  are  the 
following : 

Milk  of  Woman,  analyzed  by  M.  Peyen. 
Butter,        -         -         5-16       5-18       5  20 
Sugar  and  cheese,       7  •  80       8*10       9  ■  80 

Milk  of  Asses,  analyzed  by  M.  Peligot. 
Butter,      -         -         1-55       1-40       1'23       1'75       1-51 
Sugar  and  cheese,    10 '11       7 '97       7  34       8"25       7  -80 

Donne,  therefore,  proposes  to  estimate  the  purity  and  the  richness 
of  milk  by  means  of  the  globular  element  contained  within  it.  The 
eye  alone  will,  in  some  measure,  indicate  the  number  of  globules  con- 
tained in  the  milk;  for,  since  the  opacity  of  milk  is  due  to  the  presence 
of  the  globules,  it  may  be  concluded  that  the  milk  which  is  white  and 
opaque  is  rich  in  globules,  while  that  which  is  watery  and  transparent 
is  poor  in  the  same. 

The  microscope,  however,  is  a  more  certain  means  of  determining 
the  number  of  the  globules,  although  by  means  of  this  instrument  we 
can  only  arrive  at  an  approximative  knowledge  of  their  amount. 

In  order  to  estimate  as  nearly  as  possible  the  number  of  globules 
existing  in  the  milk,  M.  Donne  has  invented  an  apparatus  which  he 
has  termed  a  lactoscope.  By  means  of  this  instrument,  the  milk  can 
be  examined  in  very  thin  layers ;  and  in  proportion  to  the  opacity  of 
the  milk  spread  out  in  such  layers,  so  will  be  its  richness — the  deeper 
the  stratum,  the  richer  the  milk. 

There  is  one  fallacy  attending  the  use  of  this  instrument  which 
requires  to  be  noticed;  this,  however,  is  one  which  has  reference  to 
its  employment  in  testing  the  quality  of  the  milk  of  the  cow,  the  ass, 
and  the  goat,  and  not  of  the  milk  of  woman. 

The  milk  of  commerce  is  frequently  adulterated  with  substances, 
such  as  chalk  and  flour,  which  are  intended  to  heighten  its  colour 
and  opacity ;  the  presence  of  these  then  in  the  milk  would,  to  a  cer- 
tain extent,  lessen  the  value  of  the  opinion  to  be  deduced  from  an 
examination  of  the  milk  with  the  lactoscope  of  Donne. 

The  effect,  however,  of  the  admixture  of  chalk  and  flour,  in  height- 
ening the  opacity  of  milk,  is  not  so  considerable  as  might  be  supposed, 
and  this  is  especially  found  to  be  the  case  when  it  is  spread  out  in  thin 


212  ORGANIZED     FLUIDS. 

layers,  as  in  the  lactoscope.  Moreover,  the  presence  of  an  insoluble 
substance  in  the  milk  might  be  detected  by  means  of  the  microscope. 

Applied  to  the  examination  of  the  milk  of  woman,  the  lactoscope 
would  not  be  subject  to  the  above  fallacy. 

Having  now  shown  that  the  globules  constitute  an  important  ele- 
ment of  the  milk,  and  the  methods  by  which  their  number  may  be 
ascertained,  we  may,  in  the  next  place,  describe  more  particularly  the 
qualities  of  good  milk. 

Healthy  milk  may  be  defined  to  be  an  alkaline  fluid,  having  a  spe- 
cific gravity  of  about  1 :  032,  holding  in  suspension  numerous  perfectly 
spherical  and  discrete  globules,  soluble  in  ether,  and  therefore  of  a  fatty 
nature ;  and,  in  solution,  cheese  and  sugar,  together  with  various  salts. 

If,  on  the  contrary,  the  milk  be  viscous  or  acid — if  the  globules  be 
ill-formed  or  few  in  number — if  they  adhere  together  in  masses,  and 
do  not  roll  freely  and  separately  in  the  serum — if  also  this  contain  the 
colostrum  corpuscles — then  the  milk  is  either  imperfectly  elaborated 
or  diseased. 

Whenever  the  proper  globules  of  the  milk  occur  abundantly,  are  of 
the  usual  size,  and  are  equally  diffused  throughout  the  serum,  we  may 
conclude  that  the  other  nutritive  elements  of  the  milk  are  likewise 
present  in  due  proportion.     (See  Plate  XIV.  fig.  1.) 

It  must  be  held  in  mind,  however,  that  the  milk  of  different  animals 
does  not  contain  normally  the  same  relative  amount  of  nutritive 
ingredients:  thus,  the  milk  of  woman  is  especially  rich  in  cream, 
while  that  of  the  goat  and  ass  is  but  poor  in  that  element. 

POOR    MILK. 

Not  unfrequently  the  milk  is  found  to  contain  a  less  quantity  of 
globules  than  ordinary :  the  milk  in  which  a  deficiency  of  its  globular 
element  exists  appears  watery  and  transparent,  and  is  also  usually  of 
greater  specific  gravity  than  good  milk.     (See  Plate  XIV.  fig.  2.) 

This  condition  of  the  milk  is  one  of  its  most  common  as  well  as 
most  serious  states  in  its  consequences  to  the  child. 

At  the  same  time  that  the  milk  is  poor  in  globules  or  in  cream,  the 
serum  may  be  either  deficient  in  quantity,  or  it  may  be  in  excess. 

In  either  case,  such  milk,  whether  it  be  human  or  not,  is  deficient 
of  the  amount  of  the  nutritive  ingredients  necessary  for  the  growth 
and  development  of  the  child,  which,  instead  of  increasing  in  size, 
daily  diminishes,  becoming  faded  and  emaciated.  In  the  instances  in 
which  milk  containing  a  super-abundance  of  serum  is  received  into 


MILK.  213 

thj  stomach,  that  organ  becomes  distended  and  weakened  by  its 
engorgement  with  a  fluid,  the  digestion  of  which  brings  with  it  little 
or  no  nourishment. 

An  infant  whose  strength  is  reduced  by  the  poverty  of  the  milk 
given  to  it,  is  not  unfrequently  the  subject  of  diarrhoea,  which  still 
further  lessens  its  powers. 


An  opposite  condition  of  the  milk  to  that  just  described  frequently 
exists,  viz :  that  in  which  its  nutritive  principles  are  in  excess,  a  fact 
which  is  most  readily  ascertained  by  an  examination  of  the  state  of 
the  globular  element  of  the  milk:  this  being  super-abundant,  it  may, 
as  already  shown,  be  concluded  that  the  sugar  and  cheese  likewise 
occur  in  unusual  quantities.     (See  Plate  XIV.  fig.  5.) 

This  condition  of  the  milk  is  not  to  be  regarded  as  an  alteration 
of  its  qualities,  but  merely  as  an  exaggeration  of  them ;  nevertheless, 
it  is  one  which  is  often  incompatible  with  the  well-being  of  the  child. 
This  rich  milk  is  often  too  strong  for  the  digestive  powers  of  the 
child,  whose  nutrition  in  consequence  suffers:  it,  moreover,  is  some- 
times the  occasion  of  colic  and  diarrhoea. 

The  state  of  the  milk  just  noticed,  and  its  consequent  effects  upon 
the  child,  may  be  modified,  and  even  entirely  remedied,  by  a  judicious 
regulation  of  the  diet,  as  well  as  by  permitting  the  milk  to  remain  in 
the  breast  for  a  considerable  time,  the  effect  of  which  retention  is  to 
render  it  more  watery;  the  infant,  also,  should  not  be  allowed  to  take 
the  breast  except  at  long  intervals. 

At  the  same  time  that  the  globules  are  more  numerous  in  milk 
which  is  rich,  they  are  also  larger.  The  size  of  the  globules  is  like- 
wise found  to  undergo  an  increase  from  the  first  days  of  lactation, 
and  this  increase  continues  for  some  months  afterwards :  thus,  the 
globules  of  the  third  month  are  larger  than  those  of  the  first  month, 
and  those  of  the  sixth  month  still  larger,  the  number  of  the  very 
small  globules  having  diminished  very  considerably.  The  increase 
in  the  size  of  the  globules  referred  to,  is  not,  however,  so  uniform  or 
so  constant  as  to  allow  of  the  determination  from  it  of  the  age  of  the 
milk. 

ADULTERATIONS    OF    MILK. 

There  are  but  few  articles  of  general  consumption  more  adul- 
terated, and  on  which  more  frauds  are  practised,  than  the  milk. 
The  more  usual  substances  employed  for  the  purpose  of  adultera- 


214  ORGANIZED     FLUIDS. 

tion  are  water,  flour  or  starch,  chalk,  and  the  brains  of  sheep;  of 
these,  water  is  the  one  which  is  most  frequently  had  recourse  to,  and 
which  is  the  most  difficult  to  detect. 

The  effect  of  water  in  altering  the  specific  gravity  of  milk  has 
already  been  referred  to ;  and  it  has  been  shown  that  the  result  of  its 
addition  to  milk,  a  portion  of  the  cream  of  which  has  been  abstracted, 
is  to  restore  the  specific  gravity  which  usually  belongs  to  it. 

Donne  has  shown  that,  however  much  the  gravity  of  milk  may 
vary,  the  density  of  the  serum  of  the  milk  is  almost  constant.  This 
fact  is  interesting  and  important;  for,  by  a  knowledge  of  it,  the  dete- 
rioration of  milk  by  its  admixture  with  water,  or  with  some  other 
substance  of  the  same  density  with  it,  may  be  ascertained.  The 
serum  is  constantly  heavier  than  water;  adulteration  with  it  would 
then  cause  the  serum  to  exhibit  a  less  specific  gravity  than  that 
which  should  properly  characterize  it;  the  conclusion  to  be  deduced 
from  this  circumstance  being  that  the  milk  has  been  deteriorated, 
most  probably,  by  the  addition  of  water. 

The  adulterations  with  flour  and  sheep's  brains  are  readily  detected 
by  means  of  the  microscope.  The  fraud  by  the  former  may  be 
recognised  by  the  peculiar  form  of  the  flour  granules,  as  well  as  by 
the  action  of  iodine  upon  them  (See  Plate  XV.  jig.  6) ;  and  that  by 
the  latter  may  be  distinguished  by  the  detection,  in  the  fluid,  of  more 
or  less  of  cerebral  structure,  and  especially  of  the  nervous  tubuli. 

The  chalk  in  the  milk  is  readily  revealed  by  its  effervescence  with 
hydrochloric  acid,  as  well  as  by  its  weight,  which  causes  it  to  subside 
at  the  bottom  of  the  vessel  containing  the  milk. 

FORMATION    OF    BUTTER. 

Several  explanations  have  been  proposed  with  the  view  of  deter- 
mining the  exact  cause  of  the  amalgamation  of  the  cream  globules 
with  each  other,  and  the  formation  of  butter. 

Some  have  supposed  that  the  trituration  to  which  the  globules  are 
subject  in  the  churn,  determines  their  union  and  incorporation  with 
each  other ;  but  it  is  known  that  the  amalgamation  is  not  a  gradual 
process,  as  it  would  be  were  their  union  to  depend  upon  trituration, 
but  that  it  takes  place  in  a  manner  almost  instantaneous:  moreover, 
agitation  might  fairly  be  presumed  to  have  a  contrary  effect  on  the 
globules,  which  participate  in  the  properties  of  oil,  and  that  it  would 
cause  their  further  sub-division. 

A  second  hypothesis  conceives  that  a  chemical  alteration  in  the 


MILK.  215 

condition  of  the  globules  is  determined  by  the  presence  of  the  air: 
this  has  been  shown  to  be  erroneous  by  the  fact  that  butter  will  form 
in  vacuo. 

A  third  theory  presumed  that  an  acid  state  of  the  milk  always 
preceded  the  formation  of  the  butter :  this  notion  is  disproved,  since 
butter  is  formed  of  cream,  the  alkalinity  of  which  is  purposely  pre- 
served by  the  addition  of  soda  or  any  other  alkali. 

Donne  thus  explains  the  formation  of  butter :  "  The  butter  glob- 
ules," he  says,  "are  surrounded  in  the  cream  by  cheese  in  a  viscous 
state:  this  matter  isolates  the  globules  the  one  from  the  other,  and  is 
opposed  to  their  union.  The  churning  coagulates  the  cheese  in 
which  the  globules  are  imbedded,  and,  once  separated  from  this,  the 
grease  globules  unite  and  agglomerate  together  easily." 

It  is  doubtful  how  far  this  explanation,  though  more  satisfactory 
than  its  predecessors,  really  accounts  foi\the  instantaneous  formation 
of  the  butter. 

MODIFICATIONS    EXPERIENCED    BY    MILK    ABANDONED    TO    ITSELF,    AND    IN    WHICH 
PUTREFACTION    HAS    COMMENCED. 

The  first  change  which  the  milk  undergoes,  subsequent  to  its 
abstraction  from  the  system,  is  that  which  has  already  been  referred 
to,  and  which  consists  in  the  separation  of  the  globular  or  buttery 
element  of  the  milk  from  its  other  constituents,  and  its  ascension  to 
the  surface  of  the  fluid,  where  it  forms  the  layer  of  cream;  this 
change  in  the  arrangement  of  the  components  of  the  milk  is  deter- 
mined by  the  lighter  specific  gravity  of  the  proper  milk  or  butter 
globules. 

All  the  milk  globules  do  not,  however,  ascend  and  join  those  which 
constitute  the  cream :  it  is  chiefly  the  larger  ones  which  do  so,  the 
smaller  remaining  diffused  through  the  subjacent  milk,  to  which  they 
impart  the  degree  of  opacity  which  belongs  to  it. 

These  smaller  globules  are  not,  however,  equally  scattered  through 
the  skimmed  milk,  the  greater  portion  of  them  being  spread  through 
the  upper  stratum  of  it,  and  the  lower  appearing  almost  clear  and 
transparent,  containing  but  few  butter  globules,  and  these  the  smallest, 
as  well  as  the  minute  cheese  globules  already  described. 

These  changes  consist  merely  in  a  different  disposition  of  the 
normal  constituents  of  milk,  and  are  unaccompanied  by  any  alteration 
in  the  constitution  of  its  elements.  The  next  series  of  alterations 
have  reference  to  the  decomposition  of  the  milk,  and  are  attended  by 
changes  in  the  actual  state  and  composition  of  the  milk. 


216  ORGANISED     FLUIDS. 

The  first  change  experienced  by  the  milk,  indicative  of  com- 
mencing decomposition,  is  that  from  an  alkaline  to  an  acid  condition. 
This  acidity,  slight  at  first,  goes  on  increasing,  until  at  length  other 
alterations  are  produced;  thus,  the  layer  of  cream  becomes  thicker 
and  thicker,  condenses  itself  into  a  mass,  and  finally  presents  almost 
the  appearance  of  butter;  at  the  same  time  the  cheese  is  coagulated, 
and  precipitates  itself  to  the  bottom  of  the  liquid:  a  portion  of  it, 
however,  frequently  remains  suspended  in  the  milk,  in  consequence 
of  its  retaining  a  number  of  butter  globules,  which  lessen  its  specific 
gravity.  Soon,  however,  other  changes  show  themselves,  still  more 
indicative  of  putrefaction:  the  layer  of  cream  swells  up,  becomes 
more  yellow,  and  a  fungus  springs  up  upon  its  surface,  the  Penicillum 
glaucum.  This  at  first  presents  the  appearance  of  white  velvet ;  but 
afterwards,  as  soon  as  the  fungus  has  reached  the  period  of  fructi- 
fication, it  assumes  a  green  colour. 

The  idea  of  M.  Turpin,  that  this  fungus  had  its  origin  in,  and  was 
developed  from,  the  milk  globule,  scarcely  requires  a  serious  refutation. 

At  the  same  time,  the  odour  of  the  milk  undergoes  a  complete 
change :  sweet  when  it  is  fresh,  it  becomes  acid  as  it  decomposes,  and 
gives  out  more  especially  the  smell  of  cheese. 

Examined  with  the  microscope,  in  addition  to  the  fungus  alluded  to 
above,  numerous  infusory  animalcules  will  likewise  be  detected. 

Now,  the  changes  above  described,  and  which  are  experienced  by 
the  milk  of  every  animal,  will  be  more  clearly  understood  if  the  milk 
be  previously  filtered,  and  the  butter  and  the  serum  being  obtained 
separately,  those  alterations  which  ensue  in  each  be  noticed. 

It  will  be  observed,  that  it  is  the  butter,  or  non-azotised  substance, 
which  undergoes  the  acid  fermentation,  and  on  which  the  fungi  are 
principally  and  most  generally  developed. 

The  serum,  on  the  contrary,  becomes  alkaline,  and  exhibits  the 
ammoniacal  or  putrid  fermentation,  this  depending  upon  the  azotised 
principle  which  it  holds  in  solution,  viz :  the  cheese. 

It  will  be  remarked,  also,  that  the  serum,  in  changing,  does  not 
exhibit  the  striking  odour  of  cheese  which  the  milk  itself  gives  out 
under  the  same  circumstances,  and  from  which  it  may  be  concluded 
that  a  certain  amount  of  butter  is  necessary  to  produce  the  peculiar 
smell  of  cheese. 

The  phenomena  to  which  the  putrefaction  of  milk  give  rise  result, 
then,  from  two  kinds  of  fermentation ;  the  acid,  in  which  the  buttery 
element  of  the  milk  is  concerned,  and  the  alkaline,  resulting  from  the 
decomposition  of  the  caseine. 


MILK.  217 

THE    OCCURRENCE    OF    MEDICINES,    ETC.,    IN    THE    MILK. 

The  extreme  rapidity  with  which  the  formation  of  milk  from  the 
blood  is  effected  is  most  surprising,  and  is  only  equalled  in  the  animal 
economy  by  that  with  which  the  urine  is  itself  secreted. 

The  rapid  secretion  of  milk  from  the  blood  serves  to  explain  the 
almost  immediate  appearance  in  the  former  fluid  of  various  chemical 
reagents  and  articles  of  food  introduced  into  the  system  through  the 
medium  of  the  stomach. 

Thus,  many  articles  taken  as  food,  or  as  medicine,  have  been 
detected  in  the  milk  a  few  minutes  after  they  have  been  received  into 
the  stomach.  The  colouring  matter  of  madder-root,  the  odorous 
principles  of  garlic,  turpentine,  &c. — neutral  salts,  nitrate  of  potas- 
sium— have  all  been  encountered  in  the  milk. 

These  particulars  show  the  necessity  of  great  precaution  in  the 
prescribing  of  remedies  for  a  nursing  mother,  and  explain  the  great 
susceptibility  of  children  at  the  breast  to  the  influence  of  the  medicine 
administered  to  the  parent. 


[Farther  than  the  directions  already  given  for  the  examination  of  Lymph, 
Chyle  and  Blood,  it  is  not  thought  necessary  to  add  any  instruction  for  the 
study  of  the  fluids  just  treated  of,  the  manner  of  preparation  and  examina- 
tion being  precisely  the  same,  and  the  different  reagents  most  striking  in 
their  effects  having  been  fully  indicated  in  the  text. 

The  preservation  of  most  of  the  fluids  will  be  found  a  difficult  matter,  as 
most  of  the  preservative  solutions  employed  would  so  act  on  the  constituents 
of  each  fluid,  as  to  render  them  comparatively  useless.  The  corpuscles  of 
the  blood  are  easily  preserved  in  the  manner  indicated  at  the  close  of  the 
chapter  on  that  subject. 

Those  of  lymph,  chyle,  mucus,  pus,  and  milk,  are  best  preserved  in  the 
flat  cell  with  the  naphtha-water,  or  with  Goadby's  B-solution,  in  the  manner 
already  indicated  in  the  chapter  on  preservative  fluids. 

With  all  possible  care,  however,  these  preparations  will  soon  lose  their 
value,  as  the  corpuscles  will  undergo  more  or  less  change,  and  therefore 
cease  to  have  the  same  characters,  as  fresh  specimens  of  the  same  fluid.] 


218  ORGANIZED     FLUIDS. 


ART.    VI.  —  THE    SEMEN. 


The  seminal  fluid,  arrived  at  its  perfect  state,  as  when  it  is  ejacu- 
lated, is  not  a  simple  liquid,  the  secretion  of  a  single  organ,  but  is 
compounded  of  the  several  products  furnished,  though  not  in  an  equal 
proportion,  by  the  testicle,  the  epididymis,  the  vas  deferens,  the  pros- 
tate gland,  the  glands  of  Cowper,  the  vesiculae  seminales,  and  the 
follicles  of  the  urethra. 

But  the  spermatic  fluid  is  also  in  another  sense  a  compound  pro- 
duct; thus,  like  the  fluids  which  have  already  been  described,  it  is 
made  up  of  a  liquid  and  a  solid  element,  the  latter  consisting  of 
numerous  organized  particles  suspended  in  and  diffused  through  the 
former ;  these  particles  are  of  more  than  one  kind,  and  may  be  divided 
into  those  which  are  essential  and  those  which  are  non-essential: 
those  which  belong  to  the  first  category  are  the  spermatozoa,  the  sem- 
inal granules,  and  the  spermatophori;  and  those  which  appertain  to 
the  second,  are  the  mucous  corpuscles  and  epithelial  scales :  these  last 
constituents  occur  but  seldom,  and  are  difficult  to  discriminate  from 
the  seminal  granules  and  the  spermatophori. 

The  spermatic  fluid,  resulting  from  the  above  combination  of  solid 
and  fluid  elements,  is  then  usually  a  thick  semi-opaque  and  gelatinous- 
looking  substance,  of  a  grayish,  whitish,  or  yellowish  tint,  and  endowed 
with  a  peculiar  and  penetrating  odour,  which  Wagner  states  does  not 
belong  to  the  sperm  previous  to  its  departure  from  the  testicle  itself. 

It  is,  above  all,  the  spermatozoa,  from  the  liveliness  of  their 
motions,  the  variety  of  their  forms,  the  peculiarity  of  their  develop- 
ments, and  their  functional  importance,  which  impart  interest  to  the 
study  of  the  spermatic  fluid,  and  which  the  microscope  has  shown  to 
occur  in  it  in  such  vast  numbers. 

SPERMATOZOA. 

The  spermatozoa*  are  the  most  distinctive,  as  well  as  the  most 
interesting,  constituent  of  the  semen,  and  once  detected,  the  nature 
of  the  fluid  under  examination  can  no  longer  be  doubted. 

*In  reference  to  the  discovery  of  the  spermatozoa,  the  following  passages  are  con- 
tained in  Leeuwenhbek  (Opera,  t.  iv.  p.  57)  :  "N.  Hartsoeker  (Prccven  der  Doorsich- 
ikunde,  s.  Specimina  dioplrices,  p.  223)  says  that  he  made  known  the  spermatic 
animalcules  in  1678,  in  the  "Journal  des  Savants."    I  attribute  the  discovery  to 


THE    SEMEN,  219 

Each  spermatozoon  consists  of  two  portions,  an  expanded  part,  to 
which  has  been  assigned  the  several  names  of  "disc,"'  "head,"  and 
"body,"  and  an  attenuated  extremity,  which  is  called  "tail." 

The  spermatozoa  present  great  varieties  in  size  and  form:  these 
variations  are,  for  the  most  part,  constant  in  a  natural  family  and 
genus,  and  are  always  so  in  a  simple  species :  thus,  a  knowledge  of 
the  particulars  of  form  and  size  of  the  seminal  animalcules  is  fre- 
quently sufficient  to  distinguish  many  groups,  genera,  and  individuals 
from  each  other:  spermatozoa  are,  therefore,  capable  of  affording 
assistance  in  classification. 

Form. 

In  the  class  Mammalia  especially,  with  which,  in  this  paper,  we  are 
chiefly  concerned,  the  spermatozoa  vary  greatly  in  shape;  but  in  sev- 
eral of  the  more  natural  groups  of  that  class,  one  determined  form  and 
magnitude  may  be  detected  throughout  the  different  species  consti- 
tuting such  groups. 

In  man,  and  in  some  animals  which  approach  near  to  man  in  their 
organization,  the  spermatozoa  are  small,  the  head  or  disc  is  ovate,  the 
narrow  extremity  forming  the  summit  of  the  disc,  and  the  tail,  pro- 
ceeding from  its  broader  end,  diminishes  in  size  from  its  origin  to  its 
termination,  which  is  so  fine,  that  its  extreme  point  can  with  diffi- 
culty be  discerned.     (See  Plate  XVI.  fig.  1.) 

In  the  rat  and  m  the  mouse  the  seminal  animalcules  are  large,  and 
their  form  peculiar ;  the  head  is  half  sagittate,  and  moveable  upon  the 
tail,  which  is  long,  and  attached  not  to  the  base  of  the  arrow-like 
head,  but  to  its  side:  frequently  the  head  is  curved,  in  which  case  it 
resembles  the  blade  of  a  curved  cimeter.     (See  Plate  XVII.) 

In  the  guinea-pig,  also,  the  magnitude  of  the  spermatozoa  is  great, 
and  the  shape  remarkable :  in  this  animal  the  head  is  large,  ovate, 
concave  on  one  side,  and  convex  on  the  other,  the  tapering  and  elon- 
gated cauda  arising  from  the  narrow  end  of  the  oviform  head,  which 
may  be  compared  in  form  to  a  mustard-spoon.     (See  Plate  XVII.) 

Hamm.  He  brought  me,  in  1677,  some  gonorrhoea!  matter,  in  which  he  found  ani- 
malcules with  a  tail,  which,  according  to  him,  were  produced  by  the  effect  of  decom- 
position. I  afterwards  examined  fresh  human  semen,  and  I  then  perceived  the  same 
bodies.  They  were  in  motion,  but  in  the  liquid  portion;  in  the  thick  part  they 
remained  immoveable.  They  were  smaller  than  the  corpuscles  of  the  blood,  rounded, 
obtuse  before,  pointed  behind,  with  a  tail  five  or  six  times  as  long  as  the  body." 
The  description  of  Leeuwenhoek  appeared  for  the  first  time  hi  the  Philosophical 
Transactions,  December,  1677,  and  January  and  February,  1678. 


220  ORGANIZED     FLUIDS. 

In  birds,  two  singular  types  occur,  the  one  characteristic  of  the 
order  Passeres,  the  other  typical  of  the  Rapaces,  Scansores,  Gallince, 
Gralla,  and  Palmipedes.  In  the  first,  the  head  of  the  spermatozoon 
is  elongated  and  spiral,  resembling  a  corkscrew;  the  number  of  coils 
and  the  acuteness  of  the  angles  vary  in  different  species ;  usually 
two,  three,  or  four  turns  are  described;  the  attenuated  and  greatly 
produced  tail  proceeds  from  the  finer  end  of  the  spire,  and  between  it 
and  the  body  no  exact  line  of  demarcation  exists.  (See  Plate  XVI. 
Jig.  2.)  In  the  second,  there  is  a  distinct  division  into  head  and  tail, 
and  the  former  is  elongated,  as  in  the  order  Passeres;  but,  in  place 
of  being  spirally  coiled,  is  straight;  the  tail,  arising  abruptly  from  the 
body,  is  of  great  tenuity,  of  equal  diameter,  and  the  length  exceeding 
but  little  that  of  the  body. 

The  various  forms  assumed  by  the  spermatozoa  among  the  other 
vertebrate  and  invertebrate  animals,  it  is  unnecessary  here  to  describe : 
the  shape  of  those,  however,  belonging  to  the  Tritons  and  Salaman- 
ders, from  their  great  peculiarity,  may  be  briefly  noticed.  At  the 
junction  of  the  body  and  tail  of  each  spermatic  animalcule  an  enlarge- 
ment exists,  the  excessively  attenuated  caudal  extremity  being  curved 
spirally  round  the  body. 

The  effect  of  water  in  modifying  the  form  of  the  spermatozoa  is 
remarkable,  it  frequently  causing  them,  when  applied  in  large  quan- 
tities, to  coil  up  and  form  themselves  into  rings :  this  effect  of  the 
application  of  water  is  supposed  to  depend  upon  some  hygroscopic 
property  possessed  by  the  spermatozoa. 

Frequently  the  spermatozoa  are  seen  to  occur  on  the  field  of  the 
microscope,  grouped  together  in  bundles,  the  bodies  all  lying  one  way, 
and  fitting  by  their  concavities  into  each  other.  (See  Plate  XVII.) 
This  arrangement,  as  will  be  seen  hereafter,  is  connected  with  the 
evolution  of  the  spermatozoa. 

Occasionally,  in  man  and  other  animals,  the  head  and  tail  are  sepa- 
rated from  each  other,  and  lie  apart;  this  separation  is  doubtless 
either  the  result  of  violence  or  the  effect  of  decomposition.  Henle* 
states  that  he  has  seen  the  tail  move  independently  of  the  head. 

Size. 

Much  diversity  exists  in  the  size  of  the  spermatozoa  in  different 
animals,  although  but  little  difference  can  be  detected  in  those  of  the 
same  individual.     Wagner,  however,  has  made  the  observation  that 

*  Ajiat.  Gen.  p.  534. 


THESEMEN.  221 

their  magnitude  varies  greatly  in  different  individuals  of  the  same 
species.  These  variations  are,  however,  of  course,  confined  within 
certain  narrow  limits.  In  the  Mammalia,  the  spermatozoa  of 
man  are  among  the  smallest,  while  those  of  the  guinea-pig  and  rat 
are  among  the  largest  hitherto  discovered. .  In  the  birds  the  seminal 
animalcules  of  the  order  Passer es  are  very  large,  and  especially  those 
of  the  chaffinch. 

Structure. 

When  first  the  spermatozoa  were  discovered,  and  their  lively 
motions  observed,  much  reluctance  was  entertained  to  regard  them 
as  independent  animals  or  beings;  and  upon  this  point,  even  among 
modern  physiologists,  there  is  still  an  absence  of  accord,  some  of 
them  attempting  to  explain  the  movements  exhibited  on  purely 
physical  principles. 

Not  many  years  ago,  a  celebrated  and  talented  continental  observer 
thus  expressed  himself,  in  terms  more  ingenious  than  accurate,  in 
reference  to  the  nature  of  the  spermatozoa: 

"When  we  place  upon  the  object-glass  of  the  microscope  the 
semen  of  a  subject  who  enjoys  all  the  energy  of  his  generative 
faculty,  we  there  see  corpuscles  more  or  less  rounded  or  oval,  having 
a  sort  of  caudiform  appendix :  some  have  made  animalcules  of  these 
little  bodies,  since  they  have  seen  that  they  move,  and  have  believed 
to  have  recognised  in  their  movements  a  determined  direction,  a 
character  which  they  thought  could  only  appertain  to  animated 
beings.  And  as  among  the  microscopic  animalcules  which  they 
knew  there  are  those  which  are  provided  with  a  tail  more  or  less 
prolonged  and  more  or  less  dilated,  they  have  assimilated  to  them  the 
little  animalcules  of  the  semen,  and  have  made  them  Cercarice. 

"But  you  are  about  to  see  that  the  conformation  and  the  move- 
ments of  the  corpuscles  in  question  may  be  explained  naturally, 
without  our  being  obliged  to  have  recourse  to  the  hypothesis  of  which 
I  have  spoken.  It  is  certain  that  we  find  in  the  sperm  little  gelatini- 
form  masses,  more  or  less  rounded,  oval,  and  having  one  part 
prolonged  into  the  form  of  a  tail,  like,  in  a  word,  to  the  drawings 
which  Buffon  and  many  other  observers  have  given  us  of  the  pre- 
tended spermatic  animalcules.  These  little  masses  float  in  a  material 
less  consistent  than  themselves,  and  even  fluid.  But  at  first  their 
oval  form  results  evidently  from  the  manner  in  which  they  reflect  the 


222  ORGANIZED     FLUIDS. 

light,  and  afterwards  as  the  fluid  in  which  they  are  suspended — a  fluid 
which  is  itself  more  or  less  viscous — attaches  itself  strongly  to  them, 
it  results  that  in  the  microsco-chemical  movements  which  take  place 
in  the  sperm,  the  corpuscles  which  it  encloses  seem  to  have  a  tendency 
to  escape  from  the  kind  of  glutinous  material  which  contains  them. 
This  material,  seeking,  if  we  may  express  it  thus,  to  retain  them, 
accompanies  them  to  the  situation  only  where  they  find  themselves  to 
be  arrested  by  a  filamentous  prolongation,  which  presents  sufficiently 
well  the  appearance  of  a  tail,  and  even  of  a  flexible  tail,  by  reason  of 
the  lateral  movements  which  the  little  body  makes  in  its  progression. 
There  is  merely  in  all  this,  as  you  see,  a  mechanical  phenomenon,  and, 
in  the  movement  which  there  takes  place,  but  a  physical  effect  of  the 
contact  of  two  materials  of  different  densities ;  contact  which  pro- 
vokes these  materials  to  mingle  together  and  to  form  but  one,  as 
arrives  at  the  end  of  a  time  more  or  less  long.  Abandon  the  semen 
to  itself,  taking  care  that  its  watery  part  cannot  evaporate  by  placing 
it  in  an  atmosphere  saturated  with  humidity,  at  the  end  of  a  certain 
time  the  mixture  of  the  two  materials  will  be  complete,  and  you  will 
perceive  no  longer  any  thing  but  a  homogeneous  fluid;  the  pretended 
animalcules  have  disappeared. 

"If  we  wish  to  show  you  at  the  same  time  veritable  microscopic 
animalcules  and  the  little  gelatiniform  masses  which  move  in  the 
vehicle  of  the  sperm,  you  will  find  a  great  difference  between  the 
first  and  these  last.  I  may  fortify  my  opinion  on  this  subject  with 
that  of  Buffbn  and  Spallanzani,  who  have  denied  that  the  masses  of 
which  I  speak  wrere  animalcules. 

"Among  the  persons  who  have  admitted  the  existence  of  these 
beings,  there  are  those  who  have  carried  their  pretension  so  far  as  to 
class  them  in  genera  and  species  by  taking  the  form  of  the  dilated 
extremity  for  the  principal  zoological  character.  Some  micrographers, 
also,  remarking  the  differences  in  the  corpuscles  of  the  sperm, 
according  as  one  procures  this  liquid  from  the  testicle,  the  vesiculse 
seminales,  or  after  its  ejaculation,  have  pretended,  from  that  circum- 
stance, to  describe  a  series  of  evolutions  in  the  development  of  these 
so-called  Cercarice.  They  have  told  us  that  these  animals  do  not 
exist  in  the  product  which  occupies  our  attention  at  the  moment  that 
it  is  formed;  that  they  appear  but  in  the  vesiculae  seminales;  that  in 
these  they  are  as  yet  but  simple  globular  animals;  that  in  their 
progress  they  become  developed  by  the  production  of  their  caudal 
prolongations.     Lastly,  it  has  been  pretended — doubtless  with  the 


THE     SEMEN.  223 

design  of  marking  with  ridicule  the  opinions  which  we  have  reported — 
it  has  been  pretended,  I  say,  that  the  spermatic  infusorias  became 
among  us,  for  example,  veritable  homuncules,  having  little  arms, 
little  legs,  &c.  But  this  is  sufficient  in  itself  to  put  us  on  our  guard 
against  an  optical  illusion  which  has  unfortunately  seduced  a  great 
number  of  persons,  from  Leeuwenhoek,  one  of  its  first  favourers,  even 
to  MM.  Prevost  and  Dumas,  who  in  these  latter  days  have  still  main- 
tained the  existence  of  the  spermatic  animalcules." 

In  the  present  day,  it  is  needless  to  enter  into  any  refutation  of  the 
above  views ;  it  cannot,  however,  fail  to  be  observed  by  the  reader, 
that  they  are  weakest  just  where  they  should  exhibit  the  most  strength, 
that  is,  in  the  explanations  given  as  to  the  form  and  motions  of  the 
spermatozoa. 

Those  physiologists  who  deny  the  animality  of  the  spermatozoa 
would,  of  course,  be  very  reluctant  to  admit  of  the  existence  of  any 
thing  like  organization  in  them;  while  those,  on  the  other  hand,  who 
entertained  a  belief  in  their  animal  nature,  would  be  most  anxious  to 
establish  the  fact  of  such  organization. 

The  greatest  possible  difference  of  opinion,  then,  exists  as  to  whether 
the  spermatozoa  are  organized  or  not,  and,  if  organized,  as  to  the 
extent  to  which  they  are  so. 

In  the  centre  of  the  disc  of  the  spermatozoa  of  man  and  some 
other  animals  a  light  spot  has  been  observed ;  this  some  have  imag- 
ined to  be  a  stomach;  others,  again,  have  rejected  this  idea,  and  thus 
account  for  its  presence :  the  disc,  they  say,  is  not  ot  equal  thickness, 
and,  like  the  red  blood  corpuscle,  is  thinnest  in  the  centre,  and  which 
part,  therefore,  exhibits  a  lighter  tint  than  the  remainder:  this  latter 
view  is  most  probably  the  correct  one.  The  first  opinion  is  enter- 
tained by  Valentin,  and  the  second  by  Dujardin  and  Henle.  Miiller 
conceived  the  spot  in  question  to  be  a  nucleus.* 

Leeuwenhoek  remarked  upon  the  spermatozoa  of  the  ram  two 
clear  spots;  at  another  time,  numerous  little  points  in  the  interior;  a 
third  time,  two  semi-lunar  striae,  united  by  a  longitudinal  line;  he 
figures  also  in  those  of  the  rabbit  a  multitude  of  little  globules — one 
of  them,  larger  than  the  rest,  being  placed  near  the  tail. 

Gerber  assigns  a  most  complex  structure  to  the  spermatic  animal- 
cules of  the  guinea-pig,  describing  stomachs  similar  to  those  of  the 
poly  gastric  infusorise,  an  anus  and  sexual  apparatus;  and  conceiving 

*Muller's  Physiology,  p.  635. 


224  ORGANIZED     FLUIDS. 

the  existence  of  these  several  parts  to  have  been  established,  he  thus 
expresses  himself  in  reference  to  the  nature  of  spermatozoa  in  general : 
"The  compound  organization  of  the  seminal  animalcules  and  their 
production  by  no  equivocal  generation,  but  in  particular  sexual 
organs,  and  by  the  means  of  ova,  to  all  appearance  proclaim  their 
affinity  to  the  Entozoa."* 

Valentin  f  has  described  an  almost  similar  amount  of  organization 
in  the  spermatozoa  of  the  bear:  "The  clear  spermatozoa  of  the  bear," 
he  writes,  "which  in  external  form  approach  those  of  the  rabbit, 
present  distinct  traces  of  internal  organization,  to  wit,  an  anterior 
and  posterior  haustellate  mouth,  and  internal  cavities  or  convolutions 
of  an  intestine." 

Again,  Dujardin  J  has  described  and  figured  certain  irregular  knots 
and  lobular  enlargements  at  the  root  of  the  tail  of  the  human  sperma- 
tozoa; these  have  been  noticed  by  Wagner,  who  believes  that  they 
occur  only  as  the  effects  of  certain  alterations  experienced  by  the 
animalcules  in  consequence  of  their  long  stay  in  urine,  and  especially 
when  this  fluid  has  contained  at  the  same  time  a  quantity  of  puriform 
sediment. 

Wagner  likewise  points  out,  as  occurring  now  and  then,  but  by  no 
means  constantly,  a  small  prominence  or  trunk-like  process  situated 
on  the  anterior  part  of  the  body  of  human  spermatozoa:  this,  or  a 
similar  projection,  he  also  states  to  be  much  more  regularly  present 
in  the  seminal  animalcules  of  the  bat,  in  which  they  occur  as  pointed 
spines.  The  same  observer  has,  moreover,  noticed  upon  one  or  two 
occasions  the  caudal  end  of  the  body  to  be  double,  bifid,  or  forked, 
and  once  too  the  body  appeared  to  be  double,  as  in  a  bicephalous 
monster.§ 

The  above  comprise  all  the  particulars  which  have  hitherto  been 
promulgated  in  reference  to  the  organization  of  the  spermatozoa; 
scarcely  any  one  of  them  has,  however,  been  sufficiently  established : 
we  are  therefore  not  authorized  to  receive  them  as  proved,  and  to 
build  any  reasoning  upon  them :  the  most  which  we  are  warranted 
in  deducing  from  them  amounts  to  this,  that  traces  of  organization 
have  been  discovered  in  the  spermatozoa,  the  precise  nature  and 
extent  of  which  have  not  as  yet  been  satisfactorily  determined. 

*  Gerber's  General  Anatomy,  translated  by  Gulliver,  p.  337. 

f  Repertorium,  1837. 

I  Ann.  des  Sciences  Nat.  viii.  p.  293.  plate  9.  1827. 

§  Elements  of  Special  Physiology,  pp.  10.  16. 


THE     SEMEN.  225 

Notwithstanding  his  observations,  given  above,  Wagner*  states 
that  he  has  been  utterly  unable,  after  varied,  repeated,  and  long- 
continued  examination,  to  discover  true  internal  organs  in  the  sperma- 
tozoa. Sieboldf  has  also  been  equally  unsuccessful  in  his  endeavours 
to  detect  such,  as  also  HenleJ  and  Koelleker. 

The  determination  of  the  fact  that  the  spermatozoa  are  possessed 
of  even  the  smallest  amount  of  organization,  would  involve  their 
classification  in  the  animal  kingdom,  and  the  description  of  the 
different  forms  which  occur  as  so  many  distinct  species. 

The  view  of  the  animal  nature  of  the  spermatozoa  would  appear 
to  gather  strength,  and  to  admit  almost  of  positive  demonstration,  by 
reference  to  their  very  remarkable  motions. 

MOTIONS    OF    THE    SPERMATOZOA. 

It  is  impossible  that  any  thing  can  convey  a  more  just  idea  of  life 
than  the  spectacle  of  a  drop  of  the  seminal  fluid  in  which  the 
spermatozoa  are  in  active  and  ceaseless  motion. 

Sometimes,  indeed,  when  the  semen  is  thick  and  tenacious,  the 
movements  of  the  contained  spermatozoa  are  but  feeble,  the  density 
of  the  liquor  seminis  presenting  too  great  an  impediment  to  the  free 
motion  of  these  minute  creatures. 

Often,  however,  in  such  cases,  when  the  fluid  has  been  diluted  with 
water  or  with  some  other  liquid,  as  serum  or  milk,  of  less  density 
than  itself,  the  spermatozoa,  being  now  set  at  liberty,  will  frequently 
be  seen  to  resume  their  locomotive  powers,  and  to  move  about  with 
the  greatest  activity.  All  the  spermatozoa,  however,  contained  in  a 
drop  of  semen  which  has  undergone  dilution  will  not  start  into 
motion  at  once;  many  of  them  will  remain  for  a  time  perfectly 
motionless,  and  then  suddenly,  and,  as  it  were,  by  an  act  of  volition, 
begin  to  move  themselves  in  all  directions. 

Mode  of  Progression. 

The  motions  of  the  spermatozoa  are  effected  principally  by  means 
of  the  tail,  which  is  moved  alternately  from  side  to  side,  and  during 
progression  the  head  is  always  in  advance. 

The  strength  of  the  spermatozoa  is  considerable,  it  enabling  them, 
when  they  are  immersed  in  either  blood  or  milk,  to  cast  aside,  with 

*  Loc.  cit.  p.  17.  f  Siebold  in  Weigman's  Archiv.  1838. 

\  Anatomie  Generate,  t.  vii.  p.  531. 
15 


226  ORGANIZED     FLUIDS. 

the  greatest  ease,  the  globules  which  may  present  themselves  to 
impede  their  progress. 

The  spiral  spermatozoa  of  the  Passeres  advance  by  a  movement 
of  rotation  of  the  body,  the  tail  remaining  extended  and  motionless, 
acting  rather  as  a  rudder  than  as  an  organ  of  locomotion.  The 
spermatozoa  of  the  other  orders  of  birds,  and  which  consist  of  a 
cylindrical  body  to  which  a  short  and  attenuated  tail  is  attached, 
"scull  themselves  forward  with  their  tails,  either  striking  them  slowly 
and  with  wide  sinuosities,  or  more  quickly  and  shortly,  as  when  a 
whip  is  shaken ;  they  thus  advance  in  circles  with  a  quivering 
motion,  holding  the  body  extended  in  a  straight  line,  although  they 
also  now  and  then  bend  this  in  various  directions  from  side  to  side."* 

The  spermatozoa  of  the  tritons  and  salamanders  usually  lie  coiled 
up  in  the  form  of  a  ring,  and  seem  to  spin  round  as  upon  a  pivot ;  at 
the  same  time  a  second  wavy  and  tremulous  motion,  like  that  pro- 
duced by  cilia,  is  observed;  this  arises  from  the  rapid  rotatory  or 
spinning  movement  of  the  very  delicate  tail  with  which  the  sperma- 
tozoa of  these  animals  are  furnished,  and  which  is  wound  spirally 
round  the  body.  Wagner  at  one  time  entertained  the  notion,  which, 
however,  he  subsequently  discarded,  that  the  wavy  motion  referred 
to  was  produced  by  a  ciliary  apparatus.  Sometimes  the  coiled 
spermatozoa  have  been  seen  to  unrol  themselves  and  to  cross  the 
field  of  the  microscope  with  slow  serpentine  motions. 

Furthermore,  in  the  various  motions  executed  by  the  spermatozoa, 
they  exhibit  all  the  characters  of  volition;  thus  they  move  sometimes 
quickly,  at  others  slowly,  alter  their  course,  stop  altogether  for  a  time, 
and  again  resume  their  eccentric  movements.  These  movements  it 
is  impossible  to  explain  by  reference  to  any  hygroscopic  properties 
which  may  be  inherent  in  the  spermatozoa,  they  appear  to  be  so 
purely  voluntary.  A  strong  argument,  therefore,  in  favour  of  the 
independent  animality  of  the  spermatozoa  may  be  derived  from  a 
consideration  of  the  nature  of  their  motions. 

Duration  of  Motion. 

The  length  of  time  during  which  the  motions  of  the  spermatozoa 
continue,  either  after  the  escape  of  the  seminal  fluid,  or  after  the 
death  of  the  animal,  varies  very  considerably;  thus  it  is  maintained, 
for  a  longer  period  in  warm  weather  than  in  cold,  and  when  the 
semen   is   retained  within   its   natural   reservoirs   than  when  it  is 

*  Wagner's  Elements,  p.  18. 


THE     SEMEN. 


227 


removed  from  those  receptacles.  The  spermatozoa  of  some  animals 
also  preserve  their  powers  of  locomotion  for  a  longer  period  than 
those  of  others ;  thus,  the  seminal  animalcules  of  birds  die  very  soon 
after  the  death  of  the  bird;  according  to  Wagner,  frequently  in  from 
fifteen  to  twenty  minutes;*  occasionally,  nevertheless,  the  sperma- 
tozoa have  been  found  moving  in  birds  which  have  not  been  opened 
until  some  hours  have  elapsed  after  death:  those  of  the  Mammalia 
have  been  observed  in  motion  for  a  very  long  period  after  the  removal 
of  the  semen  from  the  testicle,  and  after  the  death  of  the  animal; 
but  it  is  in  fishes  that  the  spermatozoa  retain  their  powers  of  locomo- 
tion out  of  the  body  for  the  longest  period,  even  for  many  days. 

According  to  Dujardin,f  the  spermatozoa  live  thirteen  hours  in  the 
testicles  of  the  mammalia  after  the  death  of  the  animal. 

LamperhoffJ  has  found  living  semen  in  the  vesiculse  seminales  of 
dead  men,  in  which  the  spermatozoa  retained  the  power  of  locomotion 
for  twenty  hours. 

Wagner§  has  observed  them  exhibiting  motion  at  the  end  of 
twenty-four  hours. 

Donn6||  states  that  he  has  watched  their  movements  for  an  entire 
day,  and  that  he  has  observed  them  in  motion  even  on  the  second  day. 

It  is,  above  all,  in  the  place  of  their  final  destination  that  the 
spermatozoa  live  for  the  longest  period ;  thus,  Leeuwenhoek  first, 
and  other  observers  subsequently,  have  discovered  them  in  a  living 
condition  in  the  uterus  and  Fallopian  tubes  of  a  bitch  seven  days 
after  connexion,^!  and  Bischoff**  has  found  them  alive  eight  days 
after  intercourse  in  the  rabbit. 

The  great  length  of  time  during  which,  under  certain  circum- 
stances, the  spermatozoa  retain  the  faculty  of  locomotion,  furnishes 
another  strong  argument  in  favour  of  their  independent  vitality. 

Effects  of  Reagents. 

The  seminal  animalcules  retain  their  locomotive  powers  for  a  very 
long  time  in  fluids  of  a  bland  nature ;  for  example,  in  blood,  milk, 
mucus,  and  pus ;  on  the  contrary,  in  reagents  of  an  opposite  character, 
and  in  those  possessed  of  poisonous  properties,  they  soon  cease  to 
move :  thus,  in  the  saliva  and  urine,  unless  these  fluids  be  very  much 


*  Wagner,  loe.  cit.  p.  21. 

\  Diss,  de  Vesical.  Semin. 

II  Cours  de  Microscopic,  p.  284. 

**  Miiller,  Archiv.  p.  16.  1841. 


f  Annates  des  Sciences  Nat. 

5  Loc.  cit.  p.  22. 

IT  Opera  Omnia,  1. 1.  b.  p.  150. 


228  ORGANIZED     FLUIDS. 

diluted,  their  motions  are  soon  destroyed,  and  immediately  cease  in 
the  acids  and  alkalies,  in  alcohol,  iodine,  strychnine,  and  the  watery 
solution  of  opium. 

The  addition  of  water  to  the  spermatic  animalcules  usually  pro- 
duces a  remarkable  effect,  increasing  greatly  for  a  time  the  rapidity 
of  their  motions,  which  after  the  lapse  of  a  minute  or  two  entirely 
cease;  this  reagent,  as  well  as  the  saliva,  exerts  a  further  peculiar 
influence  upon  them,  causing  them  to  curl  up  into  circles  or  rings. 

Poisons  introduced  into  the  system,  and  destroying  the  life,  are 
stated  not  to  affect  the  motions  of  the  spermatozoa;  an  assertion  to 
be  received  with  some  degree  of  hesitation :  in  cases  of  poisoning  by 
prussic  acid,  I  have  usually  found  the  spermatozoa  to  be  motionless, 
even  when  viewed  immediately  after  death. 

The  urine  has  the  property  of  preserving  the  spermatozoa  entire  for 
weeks  and  months ;  and  Donne1  has  detected  them  in  that  fluid  after 
an  interval  of  three  months. 

The  result,  then,  of  the  application  of  reagents,  furnishes  an  addi- 
tional argument  in  favour  of  the  animality  of  the  spermatozoa,  and 
one  which  it  would  be  difficult,  if  not  impossible,  satisfactorily  to 
controvert. 

SPERMATOPHORI. 

The  only  essential  solid  elements  contained  in  the  seminal  fluid 
arrived  at  its  perfect  state,  as  in  the  vas  deferens,  and  when  ejacu- 
lated, are  the  spermatozoa;  occasionally,  however,  there  are  encoun- 
tered in  it,  as  non-essential  constituents,  mucous  corpuscles,  epithelial 
scales,  and  the  seminal  granules :  the  spermatic  liquid,  however, 
obtained  from  the  body  of  the  testicle,  contains  not  only  the  several 
structures  already  named,  but  also  minute  and  bright  granules,  and 
the  compound  cells  or  sperm atophori,  the  bright  granules  and  the 
seminal  corpuscles  probably  represent  stages  in  the  development  of 
the  spermatophori. 

The  several  structures  now  named  are  all  occasionally  met  with  in 
the  ejaculated  semen;  their  occurrence  in  it  is  to  be  regarded  rather 
as  accidental  than  as  essential ;  the  spermatophori  belong  to  the  tes- 
ticle, the  tubuli  seminiferi  of  which  in  many  cases  are  almost  filled 
by  them. 

The  spermatophori  differ  greatly  from  each  other,  both  as  respects 
size  and  the  number  of  secondary  cells  or  nuclei  contained  within 
them ;  the  smaller  parent  cells  are  about  TJ\  o  °f  an  mcn  m  diameter 


THE     SEMEN.  220 

in  man,  and  contain  usually  but  a  single  nucleus,  while  the  larger 
ones  attain  the  magnitude  of  j ±-q  of  an  inch  in  breadth,  and  include 
not  unfrequently  as  many  as  six  or  eight  nuclei,  or,  more  properly 
speaking,  secondary  cells.  Between  the  two  extreme  sizes  given, 
every  gradation  presents  itself,  and  many  spermatophori  contain  but 
one,  two,  three,  or  four  nuclei,  which  are  the  numbers  most  frequently 
encountered. 

The  secondary  cells,  like  the  primary  or  parent  ones,  are  globular, 
and  those  contained  within  the  same  parent  cell  are  usually  of  the 
same  dimensions ;  the  centre  of  these  cells  occasionally  presents  a 
bright  spot.     (See  Plate  XVI.  fig.  1.) 

Not  unfrequently  certain  large  and  perfectly  transparent  cells  are 
encountered;  these  are,  in  all  probability,  the  older  spermatophori, 
the  contents  of  which  have  been  discharged. 

It  would  appear,  therefore,  that  the  development  and  dissolution  of 
the  spermatophori  are  effected  entirely  within  the  tubes  of  the  testes. 

Cells,  which  Wagner  has  denominated  seminal  granules,  occur,  as 
already  remarked,  mixed  up  with  the  undoubted  spermatophori ;  these 
first  are  smaller,  and  do  not  contain  nuclei;  whether  they  are  really 
distinct  from  the  latter,  it  is  not  easy  to  determine.  If  but  one  kind 
of  cell  occurs  in  the  testicle,  then  a  double  function  must  be  assigned 
to  it :  thus,  in  the  first  place,  the  secretion  of  the  liquor  seminis  must 
be  effected  by  it ;  and,  in  the  second,  the  development  of  the  sperma- 
tozoa occurs  within  its  cavity;  in  which  case  the  spermatophori 
would  be  the  homologues  of  the  cells  of  other  glands,  only  in  so  far  as 
they  discharge  an  analogous  function,  and  are  secreting  organs ;  in 
the  ulterior  office  allotted  to  them,  that  of  being  receptacles  in  which 
the  spermatozoa  are  evolved,  they  stand  alone  in  the  animal  economy, 
and  are  certainly  without  analogues  in  any  other  gland  of  the  body. 

It  is  most  probable,  however,  that  two  kinds  of  cells  coexist  in  the 
testes — the  one  secreting  and  corresponding  with  the  cells  of  other 
secerning  organs ;  the  other  kind,  of  a  peculiar  nature,  without  par- 
allel in  the  animal  economy,  and  devoted  to  the  development  of  the 
spermatozoa. 

DEVELOPMENT    OF    THE    SPERMATOZOA. 

Not  the  least  interesting  part  of  the  history  of  the  spermatozoa  is 
that  having  reference  to  their  development. 

Wagner  was  the  first  to  state  that  the  spermatozoa  are  developed 
within  the  spermatophori  just  described. 


230  ORGANIZED     FLUIDS. 

This  interesting  discovery  of  Wagner  has  been  amply  confirmed 
by  the  extended  observations  of  Kcelliker,  Siebold,  Valentin,  and 
Lallemand. 

Wagner  thus  describes  the  evolution  of  the  spermatic  animalcules 
in  the  spermatophori  of  a  bird :  "  In  the  course  of  their  development, 
a  fine  granular  precipitate  is  observed  to  form  between  the  included 
nuclei,  by  which  these  are  first  obscured  and  then  made  to  disappear, 
and  linear  groupings  are  produced,  which  anon  proclaim  themselves 
as  bundles  of  spermatozoa,  already  recognisable  by  slight  traces  of  a 
spiral  formation  of  one  extremity.  (See  Plate  XVI.  fig.  2,  g.)  It 
were  hard  to  say  whether  the  fine  granular  precipitate  is  to  be 
regarded  as  the  product  of  a  process  of  resolution  occurring  to  the 
nuclei,  or  a  new  formation ;  as,  also,  whether  the  spermatozoa  spring 
out  of  or  only  in  and  amidst  the  yolk-like  matter,  or  matter  that  is  at 
all  events  comparable  to  the  yolk  of  eggs  in  general.  The  vesicles 
now  assume  an  oval  form  (see  Plate  XVI.  fig.  2,  h),  the  globules  dis- 
appear, the  granular  contents  diminish;  the  seminal  animalcules  are 
well  grown,  and  lie  bent  up  within  the  cyst ;  their  spiral  ends  are 
more  conspicuous.  The  delicate  covering  (involucrum)  is  now 
drawn  more  closely  around  the  bundle  of  spermatozoa  it  includes,  and 
where  it  covers  their  spiral  ends  anteriorly  it  assumes  a  pyriform  out- 
line (see  Plate  XVI.  fig.  2,  i),  and  at  the  opposite  extremity  is  perhaps 
at  this  time  open ;  but  it  is  difficult  to  speak  decisively  on  this  point. 
The  cysts  are  now  very  commonly  bent  nearly  at  right  angles  or  like 
knees,  but  at  length  they  appear  stretched  out  and  straight,  and  have 
attained  their  full  size.  (See  Plate  XVI.  fig.  2,  k.)  The  capsules  of 
these  vesicles  are  at  all  times,  and  especially  towards  the  end  of  their 
existence,  highly  hygroscopic;  the  addition  of  a  little  water  causes 
them  to  burst,  the  masses  of  spermatozoa  rolled  up  like  a  little  skein 
of  thread  or  silk  escape,  and  occasionally  at  this  stage  exhibit  motions 
individually,  which,  however,  while  the. animalcules  continue  in  the 
ducts  of  the  testes,  are  frequently  not  to  be  observed,  and  are  never 
either  general  or  remarkable.  The  spermatozoa,  after  the  rupture  of 
the  cyst,  advance  in  freedom  to  the  vas  deferens."* 

The  process  Wagner  states  subsequently  to  be  precisely  similar  in 
man  and  the  Mammalia,  although  it  is  more  difficult  to  follow  it  in 
them. 

The  accuracy  of  the  above  account  of  the  development  of  the 
spermatozoa  has  been  admitted  by  most  other  observers  in  all  respects 
*  Translation  of  Wagner's  Elements,  by  Willis,  pp.  25,  26. 


THE      SEMEN.  231 

save  one  important  one:  thus,  Koelliker  has  shown  that  the  evolution 
takes  place  in  the  included  or  secondary  cells,  and  not,  as  Wagner 
describes  it,  in  the  spaces  between  these,  a  single  spermatic  animal- 
cule being  formed  within  each ;  the  granules  enclosed  in  these  cells 
disappear  gradually  as  the  spermatozoon  assumes  a  definite  form,  and 
Koelliker  further  supposes  that  these  granules  constitute,  by  their  union 
with  each  other,  the  substance  of  the  spermatozoa  which  escape  from 
both  the  secondary  and  primary  cells  by  the  rupture  of  their  investing 
membranes.  When  the  spermatic  animalcules  have  escaped  from 
the  secondary  cells,  and  these  have  disappeared,  the  spermatozoa  form 
a  bundle  which  is  still  included  within  the  larger  primary  cell ;  some- 
times the  seminal  animalcules  are  irregularly  disposed  within  its 
cavity,  but  more  frequently  they  are  applied  directly  to  each  other, 
the  heads  lying  one  way,  and  the  tails  in  the  opposite  direction.  This 
disposition  of  them  is  often  preserved  even  after  their  escape  from  the 
spermatophori,  during  their  stay  in  which  the  spermatozoa  usually 
remain  quite  motionless. 

The  interesting  and  important  fact  of  the  development  of  the 
spermatozoa  in  the  secondary  cells,  or  ova,  as  they  should  now  be 
called,  Koelliker  first  ascertained  by  the  study  of  their  evolution  in 
the  guinea-pig;*  subsequently,  he  extended  his  observations,  and 
found  that  the  spermatozoa  in  man  were  evolved  in  a  manner  pre- 
cisely similar. 

Valentinf  during  his  inquiries  observed  masses  of  filaments  in  the 
mother  cells  of  the  rabbit  and  bear,  and  Hall  man  J  noticed  the  same 
thing  in  those  of  the  rays ;  he  does  not,  however,  speak  of  the  trans- 
formation of  the  included  nuclei  or  ova. 

In  the  class  of  invertebrate  animals,  it  is  most  probable  that  a  sim- 
ilar method  of  development  prevails. 

The  spermatozoa  are  not  encountered  in  equal  numbers  in  all  parts 
of  the  testicle,  the  more  remote  convolutions  of  the  tubuli  seminiferi 
containing  chiefly  the  simple  granular  cells  and  the  spermatophori, 
while  it  is  only  in  those  which  approach  near  to  the  epididymis  that 
they  occur  in  any  numbers;  in  this  situation  they  usually  lie  immedi- 
ately beneath  the  membrane  of  the  seminiferous  tube,  and  external  to 
the  spermatophori,  their  long  axes  being  disposed  in  the  direction  of 
that  of  the  tube  itself.     In  the  vas  deferens  the  spermatozoa  are  pres- 

*  Beitrag.  p.  56.  tab.  11.  fig.  20.  f  Repert.  p.  145.  1837. 

\  Muller,  Archiv.  p.  471.  1840. 


232  ORGANIZED     FLUIDS. 

ent  in  vast  numbers,  and  with  scarcely  any  admixture  of  the  other 
solid  elements  of  the  testes. 

It  is  in  the  epididymis  that  the  different  stages  of  development  of 
the  seminal  animalcules  are  best  seen  side  by  side. 

The  spring  is  by  far  the  most  suitable  period  for  the  study  of  the 
development  of  the  spermatozoa,  and  birds,  especially  those  of  the  order 
Passeres,  present  the  best  examples  in  which  to  trace  their  evolution, 
because  in  them  the  seminal  animalcules  are  large,  and  the  reproduc- 
tive function  is  excessively  active  for  a  brief  and  determined  period. 

Wagner*  has  shown  that  from  the  commencement  of  the  time  of 
moulting,  and  through  the  entire  winter,  the  testes  of  birds  undergo 
an  extraordinary  degeneration,  the  spermatozoa  and  the  spermato- 
phori  being  entirely  obliterated,  and  the  volume  of  the  testes  reduced 
to  at  least  the  twentieth  or  thirtieth  of  the  size  to  which  they  attain 
in  spring.  Thus,  the  testis  of  the  common  chaffinch  is  in  winter  not 
larger  than  a  millet-seed,  while  in  spring  it  exceeds  a  pea  in  size. 

The  same  degeneration  is  doubtless  experienced  during  winter, 
although  to  a  less  extent,  by  most  animals  of  the  class  Mammalia. 

THE    SPERMATOZOA    ESSENTIAL     TO    FERTILITY. 

The  spermatozoa  do  not  exist  in  the  testes  of  mammalia  at  all 
periods  of  life :  thus,  they  do  not  make  their  appearance  in  that  organ 
in  man  until  the  period  of  puberty,  and  they  disappear  gradually  as 
old  age  advances.  It  is  impossible,  however,  to  determine  the  time 
at  which  they  are  first  developed,  or  at  which  they  cease  to  exist  in 
that  organ,  because  the  period  of  puberty  differs  in  different  individ- 
uals, and  some  men  are  aged  in  constitution  when  others  of  the 
same  years  are  hale  and  robust.  Certain  it  is,  that  some  men  retain 
the  power  of  engendering  until  a  very  advanced  age,  of  which  fact 
the  celebrated  Parr  presents  a  memorable  example,  he  having  become 
a  father  at  the  extraordinary  age  of  142. 

The  number  also  of  the  spermatozoa  contained  in  the  seminal  fluid 
varies  in  different  individuals,  and  is  usually  in  proportion  to  the 
activity  of  the  reproductive  function,  and  this  again  is  dependent  to 
a  great  extent  upon  the  constitutional  powers  as  well  as  upon  the 
mode  of  life. 

The  activity,  then,  of  the  reproductive  faculty  in  man  is  in  many 
cases  a  good  test  of  health. 

The  above  few  facts  favour  the  idea  of  the  essentiality  of  the 
*  Elements,  pp.  28  and  29. 


THE     SEMEN.  233 

spermatozoa;  others,  however,  of  a  stronger  kind,  still  remain  to  be 
mentioned. 

Wagner  has  instituted  some  most  interesting  inquiries  in  reference 
to  the  condition  of  the  spermatozoa  in  male  hybrids,  and  especially  in 
ma^e  hybrid  birds,  and  he  finds,  that  in  them  the  characteristic  ani- 
malcules are  either  altogether  wanting,  or  occur  but  in  small  numbers, 
and  are  ill-formed  and  ill-conditioned;  the  hybrids  in  which  the  sem- 
inal animalcules  have  been  thus  found  to  be  absent  or  degenerated, 
have  been  ascertained  to  be  incapable  of  having  offspring.* 

Again,  Leeuwenhoekf  discovered  living  seminal  animalcules  in  the 
uterus  and  Fallopian  tubes  of  bitches  seven  days  after  connexion.  J 

Prevost  and  Dumas§  have  more  recently  made  the  same  observa- 
tions at  the  same  length  of  time  after  intercourse. 

Siebold||  has  detected  the  spermatozoa  in  a  living  state  in  the  uterus 
and  Fallopian  tubes  eight  days  after  connexion.  snj 

Lastly,  BischoffTl  and  Martin  Barry**  have  observed  the  sperma- 
tozoa not  merely  in  the  uterus  and  Fallopian  tubes,  but  also  on  the 
ovary  itself. 

From  these  facts  it  is  therefore  evident  that  the  spermatozoa  are 
essential  to  fecundity,  although  the  precise  manner  in  which  they 
are  so  is  still  involved  in  the  greatest  obscurity.  It  is  supposed  by 
some  observers,  that  they  make  their  way  into  the  ovum  itself:  this 
notion  is  as  yet  without  evidence  to  support  it. 

It  would  be  most  interesting  to  determine  whether  impregnation 
could  be  procured  by  the  artificial  introduction  of  semen,  the  animal- 
cules of  which  were  dead;  there  is  every  reason  to  believe  that  in  the 
many  cases  in  which  the  artificial  injection  of  the  seminal  fluid  has 

*  Loc.  cit.  pp.  30 — 34.  f  Opera  Omnia,  p.  150. 

\  Leeuwenhoek  signalized  the  discovery  of  the  living  spermatozoa  in  the  uterus 
and  Fallopian  tubes,  in  the  following  words :  "  Nudo  conspiciens  oculo,  nullum  mas- 
culum  semen  canis  in  ea  esse  dicere  debuissem;  at  eandem  mediante  bono  micro- 
scopio,  summse  mese  voluptati  immensam  viventium  animalculorum  multitudinem; 
semen  nempe  canis  masculum  contemplabar.  His  peractis,  dictam  aperiebam  tubam, 
in  fine  suae  crassitudinis,  ac  ibidem  quoque  magnam  seminis  masculi  canis  contem- 
plabar copiam,  quod  semen  illic  vivebat,  et  hoc  modo  quoque  cum  dextra  egi  tuba, 
ac  in  eadem  quoque  immensam  seminis  viventis  canis  masculi  copiam  observavi.  .  . 
Materiam  qua  matrix  concita  est,  observans,  majorem  adhuc  viventium  animalculorum 
copiam  deprehendebam." 

\  Annales  des  Scien.  Nat.  t.  iii.  p.  122. 

||  Miiller,  Archiv.  p.  16.  1841.  IT  Wagner's  Elements,  p.  66. 

**  Researches  in  Embryology,  Second  Series,  Phil.  Trans,  p.  315.  1839. 


234  ORGANIZED      FLUIDS. 

been  successful,  the  contained  spermatozoa  were  in  a  living  condition; 
and  from  all  that  is  yet  known  in  relation  to  the  animalcules,  there  is 
strong  presumption  to  believe  that  the  experiment  referred  to,  viz: 
the  introduction  of  semen,  the  animalcules  of  which  were  dead,  would 
be  unattended  with  success. 

One  remarkable  experiment  of  Spallanzani,  however,  deserves  to  be 
referred  to.  Most  observers  agree  in  saying,  that  the  spermatozoa  of 
the  frog  die  after  some  hours  of  immersion  in  water.  It  is  known, 
however,  that  Spallanzani  succeeded  in  fertilizing  the  ova  of  frogs 
with  spermatized  water,  containing  three  grainsof  seminal  fluid  to 
eighteen  ounces  of  water,  thirty-five  hours  after  the  mixture  had  been 
prepared,  and  this,  in  a  chamber  with  the  thermometer  at  from  seven- 
teen to  nineteen  degrees;  and  again,  that  in  an  ice-house,  the  ther- 
mometer being  three  degrees  above  zero,  the  spermatized  water 
preserved  its  prolific  power  for  fifty-seven  hours. 

Now,  the  tendency  of  this  interesting  experiment  is  certainly  to 
prove  the  possibility  of  fertilization  occurring  with  semen,  the  sper- 
matozoa of  which  are  dead:  this  inference  would  appear,  however,  to 
be  negatived  by  another  ingenious  experiment  of  MM.  Prevost  and 
Dumas,  who  filtered  the  seminal  fluid,  and  found  that  the  fluid  portion 
which  passed  through  the  filter  would  not  vivify  the  eggs,  while  the 
more  solid  part,  consisting  of  the  spermatozoa,  produced  the  results 
peculiar  to  the  seminal  fluid. 

Jacobi  succeeded  in  fertilizing  the  ova  of  a  carp  with  semen  which 
had  been  contained  within  the  body  of  the  fish  for  four  days;  but  it 
is  well  ascertained  that  the  spermatozoa  of  fishes  in  general  live  for  a 
much  longer  period  than  that  named.*  Some  have  supposed  that 
the  only  use  of  the  spermatozoa  is  by  their  movements  to  hasten  the 
advance  of  the  semen  towards  the  Fallopian  tubes. 

PATHOLOGY    OF    THE    SEMINAL    FLUID. 

The  quantity  of  seminal  fluid  secreted  varies  greatly  according  to 
the  age  and  constitution  of  the  individual.  In  young  men,  and  in 
those  whose  health  is  vigorous,  the  secretion  is  rapid  and  abundant; 
in  the  aged,  and  in  those  whose  vital  powers  are  feeble,  it  is  but  slow 
and  scanty.  It  is,  however,  in  severe  states  of  disease  that  the  amount 
of  seminal  fluid  secreted  is  greatly  diminished,  if  the  formation  of  it 
be  not  in  some  cases  altogether  suspended  for  a  time.     Under  the 

*  Several  most  interesting  particulars  in  reference  to  artificial  impregnation  are 
given  in  Wagner's  Elements,  chap.  iii. 


THE     SEMEN.  235 

influence  of  recovery,  the  quantity  of  semen  formed  again  undergoes 
an  augmentation. 

An  inordinate  secretion  of  the  seminal  fluid,  as  also  its  prolonged 
retention  in  the  testes,  are  sometimes  the  causes  of  involuntary  sem- 
inal discharges,  which,  however,  are  far  more  frequently  occasioned 
by  organic  weakness,  the  result  of  over-indulgence. 

If  these  emissions  be  very  frequent,  the  ejaculated  semen  will  be 
found  to  be  thin  and  watery,  and  to  contain  comparatively  few 
spermatozoa. 

It  is  unnecessary  to  describe  here  the  destructive  effects  of  these 
emissions  on  the  constitution. 

It  is  often  a  matter  of  great  importance  to  determine,  independently 
of  any  revelation  on  the  part  of  the  patient,  whether  in  any  particular 
case  seminal  effusions  exist. 

This  fact,  it  is  in  the  power  of  the  microscope,  according  to  some 
observers,  in  all  cases  to  declare  with  the  most  absolute  certainty. 

After  each  effusion  of  semen,  in  whatever  way  occasioned,  a  cer- 
tain amount  of  that  fluid  will  still  remain  behind,  adhering  to  the 
surfaces  of  the  urethra;  this,  of  course,  contains  the  seminal  animal- 
cules, which  will  be  washed  away  on  the  first  passage  of  the  urine 
through  the  urethra. 

The  great  object,  then,  is  to  establish  the  fact  of  the  existence  of 
spermatozoa  in  the  urine :  this  may  be  accomplished  in  two  ways ; 
either  by  filtration  or  decantation,  the  latter  being  perhaps  the  pref- 
erable method  of  the  two;  the  spermatozoa,  being  heavier  than  the 
urine  itself,  always  subside  at  the  bottom  of  the  vessel,  and  where 
they  may  always  be  found,  if  present  in  even  the  smallest  numbers. 

The  urine,  as  already  mentioned,  has  the  property  of  preserving 
the  seminal  animalcules,  which  may  be  detected  in  it  months  after 
their  discharge  from  the  urethra. 

M.  Donne*  states,  that  he  has  never  succeeded  in  detecting  the 
seminal  animalcules  in  the  urine,  unless  as  the  consequence  of  an 
emission  of  semen,  and  which  may  have  occurred  either  during  con- 
nexion, in  an  involuntary  manner,  or  through  masturbation.  Now, 
if  this  be  true,  the  occurrence  of  the  spermatozoa  in  the  urine  declares 
positively  the  fact,  that  a  discharge  of  semen  has  been  sustained,  and 
this  particular  is  often  in  itself  sufficient  to  enable  a  medical  man  to 
form  an  opinion  of  the  case. 

It  seems  to  me,  however,  by  no  means  sufficiently  proved,  that  an 

*  Cours  de  Microscopie,  p.  318. 


236  ORGANIZED     FLUIDS. 

escape  of  the  seminal  fluid  with  the  urine  does  not  take  place  inde- 
pendently of  any  distinct  emission.  I  am  inclined  to  think  that  such 
escape  is  an  habitual  occurrence  even  with  the  most  healthy,  especially 
with  the  continent,  and  that  by  it  the  surcharged  testes  are  relieved 
whenever  requiring  such  relief. 

This  view  is  to  some  extent  supported  by  the  observations  of  Dr. 
John  Davy*  and  Wagner  :f  the  former  excellent  observer  states 
that  on  examining  the  fluid  from  the  urethra  after  stool  in  a  healthy 
man,  he  had  always  detected  spermatozoa. 

In  connexion  with  the  above  few  remarks  on  the  pathology  of  the 
semen,  we  may  refer  to  the  observations  of  Donne"  on  the  effects  of 
an  exceedingly  acid  condition  of  the  mucus  of  the  vagina,  and  a 
very  alkaline  state  of  that  of  the  uterus  itself,  on  the  vitality  of  the 
spermatozoa. 

The  mucus  of  the  vagina,  in  its  normal  state,  is  slightly  acid,  this 
degree  of  acidity  being  perfectly  compatible  with  the  life  of  the  sem 
inal  animalcules;  but  Donn6  has  shown  that  under  some  circum- 
stances— as  from  congestion,  irritation,  or  inflammation — this  mucus 
becomes  so  strongly  acid  as  to  destroy  in  a  few  seconds  the  vitality 
of  the  spermatozoa. 

Again,  the  mucus  of  the  uterus  in  its  healthy  state  is  slightly  alka- 
line, but  not  so  much  so  as  to  exert  any  injurious  effects  upon  the 
spermatozoa;  in  conditions  of  derangement  and  disease,  however,  it 
becomes  so  alkaline,  as  Donne"  has  shown,J  that  in  like  manner  with 
the  acid  mucus  of  the  vagina,  it  kills  the  seminal  animalcules  in  a 
very  short  space  of  time. 

Now,  after  what  has  been  said  and  detailed  in  reference  to  the 
essentiality  of  the  spermatozoa,  it  can  scarcely  be  doubted  that 
women  whose  vaginal  and  uterine  secretions  are  so  disordered,  are 
inapt  to  conceive,  and  this  from  the  effect  of  their  vitiated  secretions 
upon  the  spermatozoa. 

It  would  be  interesting  to  determine  whether  the  spermatozoa  are 
ever  entirely  absent  from  the  semen  of  man:  it  is  very  probable  that 
in  certain  rare  cases  they  are  so,  and  from  the  facts  already  ascer- 
tained there  can  be  no  doubt  that  those  individuals  whose  spermatic 
fluid  is  devoid  of  its  characteristic  living  element,  would  be  wholly 
incapable  of  having  offspring. 

It  is  probable  that  in  the  impotent  the  spermatozoa  are  almost,  if 
not  entirely,  extinct. 

*  Edin.  Med.  Surg.  Jour.  vol.  ii.  p.  50.  t  Loc.  cit.  p.  21. 

t  Cours  de  Microscopie,  p.  292. 


THE     SEMEN.  237 

APPLICATIONS    OF    A    MICROSCOPIC    EXAMINATION    OF    THE    SEMEN    TO    LEGAL    MEDICINE. 

The  detection  of  the  spermatic  animalcules  is  frequently  a  matter 
of  high  interest  and  importance  in  a  medico-legal  point  of  view. 

There  are  three  classes  of  cases  in  which  the  microscope,  by 
revealing  the  presence  of  spermatozoa,  is  capable  of  forwarding  the 
ends  of  justice,  and  of  bringing  conviction  home  to  the  guilty. 

1st.  In  cases  of  suspected  violation. 

2d.  In  determining  the  nature  of  doubtful  stains  observed  on  the 
bed-clothes,  &c. 

3d.  In  unnatural  offences. 

With  respect  to  those  cases  which  come  under  the  first  division,  it 
may  be  observed  that  the  medical  testimony  on  which  these  are 
usually  decided  is  too  often  of  such  a  nature  as  to  lead  to  the  acquittal 
of  a  really  guilty  individual ;  the  medical  man,  judging  merely  from 
external  appearances,  being  compelled  to  give  evidence  either  directly 
favourable  to  the  prisoner,  or  which  is  at  best  but  of  a  doubtful 
character. 

In  suspected  violation,  then,  when  the  evidence  to  be  deduced  from 
an  outward  examination  is  insufficient  for  the  formation  of  a  satis- 
factory and  decided  opinion,  the  microscope  may  frequently  be 
employed  with  the  greatest  advantage. 

If  the  offence  imputed  has  been  committed,  and  if  connexion  has 
really  occurred,  then  by  means  of  this  instrument,  provided  too  long 
a  time  has  not  elapsed  from  the  period  of  the  occurrence,  that  is  to 
say,  a  period  not  exceeding  from  twenty-four  to  forty-eight  hours,  the 
spermatozoa  will  be  detected  in  the  mucus,  properly  examined,  and 
obtained  from  the  upper  part  of  the  vagina:  now,  the  detection  of  these 
in  such  a  situation  is  a  demonstration  that  intercourse  has  taken  place.* 

The  examination  of  the  urine  of  women  whose  persons  are  sus- 
pected to  have  been  violated  would  also  frequently  furnish  evidence 
of  the  fact  by  manifesting  the  presence  in  it  of  the  spermatozoa,  which 
in  its  passage  through  the  vagina  it  had  washed  away  from  its  walls. 

With  reference  to  the  second  class  of  cases  mentioned,  those 
requiring  for  their  satisfactory  elucidation  the  determination  of  the 
nature  of  suspicious  stains,  here  again,  by  means  of  the  microscope, 
evidence  the  most  conclusive  may  frequently  be  obtained. 

*  Donne,  in  the  Cours  de  Microscopie,  states  that  he  has  detected  the  spermato- 
zoa in  the  vaginal  mucus  of  women  admitted  into  the  hospital,  in  which  instances  it  is 
most  prohable  that  connexion  had  occurred  at  least  some  hours  previous  to  admission. 


238  ORGANIZED     FLUIDS. 

Now,  if  the  stains  in  question  be  formed  by  the  seminal  fluid,  and 
if  they  be  not  too  old,  the  microscope  applied  to  them  will  detect  in 
them  the  spermatozoa. 

With  regard  to  the  length  of  time  at  which  the  spermatozoa  may 
be  detected  in  the  matter  of  a  stain,  I  have  reason  to  think  that  this 
has  scarcely  a  limit:  I  have  myself  noticed  them  in  the  semen  several 
weeks  old,  and  they  then  appeared  to  have  undergone  scarcely  a 
single  appreciable  change,  the  spermatophori  contained  in  the  seminal 
fluid  being  equally  well  seen. 

In  examining  stains  occasioned  by  the  seminal  fluid,  it  is  advisable 
to  use  the  same  precautions  as  those  which  were  pointed  out  in 
reference  to  blood  stains,  and  to  moisten  them  with  either  serum  or 
albumen. 

The  reader's  imagination  will  suggest  to  him  numberless  cases  in 
which  the  determination  of  the  nature  of  suspected  stains  would  be 
a  matter  of  the  utmost  importance,  and  would  lead  to  the  production 
of  evidence  of  the  greatest  consequence,  and  in  no  other  way 
obtainable. 

Lastly,  with  reference  to  the  third  class  of  cases,  those  of  unnatural 
offences:  here  also  the  microscope,  by  revealing  the  presence  of  the 
spermatozoa  in  the  rectum,  or  on  some  other  part  of  the  body,  may 
throw  great  light  on  occurrences  which  otherwise  would  in  all  proba- 
bility be  buried  in  complete  oblivion  and  mystery. 

An  examination  of  this  kind  was  assigned  by  the  magistrates  in 
France  some  years  ago  to  two  physicians,  on  the  occasion  of  an 
assassination  in  a  hotel.  A  traveller  having  been  killed  by  a  young 
man  whom  he  had  received  into  his  chamber  during  the  night,  justice 
was  interested  to  know  whether  semen  would  be  found  in  the  rectum 
or  not.* 

It  is  known  that  in  death  by  hanging,  an  emission  of  the  semen 
usually  occurs,  and  this,  in  the  absence  of  other  proofs,  has  been 
adduced  as  a  sign  of  death  by  suspension.  It  would  appear,  however 
that  such  an  indication  is  not  without  its  sources  of  fallacy. 

It  is  thus  apparent  that  in  the  cases  here  referred  to,  the  microscope 
is  capable  of  affording  positive  evidence  of  a  most  important  and 
conclusive  kind;  on  the  other  hand,  the  negative  testimony  deduci- 
ble  from  its  application  in  these  cases  is  not  without  its  value. 

*  See  Annates  d'Hygiene  Publique  el  de  Medecine  Legale,  Paris,  1839,  t.  xxi.  pp. 
168  and  466. 


THE     SEMEN.  239 


SEMEN. 

[In  making  examinations  of  the  seminal  fluid,  the  purest  and  most  con- 
centrated  will  be  found  in  the  vas  deferens  or  epididymis  The  sooner  this 
is  examined  after  the  death  of  an  animal,  the  less  change  will  be  detected, 
and  the  motions  of  the  spermatozoa  will  be  most  active.  If  a  small  drop  of 
the  fluid  is  placed  on  a  plain  glass  slide,  covered  with  thin  glass,  and  placed 
in  the  field  of  the  microscope,  many  of  the  spermatozoa  will  be  seen  in  active 
motion,  with  a  ith-inch  object-glass.  It  will  be  found  better  to  dilute  the 
fluid  before  covering  it  with  the  thin  glass.  For  this  purpose,  albumen,  or 
a  little  water  which  has  -^\th  part  of  salt  or  sugar  dissolved  in  it,  will  answer, 
or,  still  better,  a  little  serum  of  the  blood.  When  properly  diluted,  the 
thin  glass  is  applied,  as  before,  and  the  seminal  animalcules  will  be  much 
better  defined  than  without  this  dilution.  The  reagents  most  striking  in  their 
effects  have  already  been  pointed  out. 

PRESERVATION. 

The  seminal  animalcules  may  be  preserved,  either  in  their  own  fluid,  or 
in  a  weak  solution  of  salt  and  water,  or  of  chromic  acid.  In  either  case, 
the  flat  cell,  or  the  thin  glass  cell,  is  to  be  employed,  and  the  cover  cemented 
with  gold-size.     In  this  condition,  they  will  keep  for  many  years.] 


UNORGANIZED     FLUIDS. 


ART.    VII.  — SALIVA,    BILE,    SWEAT,   URINE. 

The  fluids  comprised  under  the  heading  of  Unorganized  Fluids 
differ  from  those  of  the  first  division,  viz:  the  Organized,  in  that 
they  do  not  contain,  as  essential  elements,  organized  structures;  solid 
organic  particles  are  indeed  usually  to  be  encountered  in  them,  but 
these  are  to  be  regarded  either  as  accidental,  or  at  all  events  as  non- 
essential adjuncts,  and  which  appertain  usually  to  the  structure  of 
those  organs  from  which  the  fluids  have  themselves  proceeded. 

The  presence  and  nature  of  the  solids  contained  in  the  Unorgan- 
ized Fluids  serve  to  indicate,  to  a  considerable  extent,  the  condition 
of  the  glands  by  which  they  have  been  secreted,  and  thus  frequently 
throw  great  light  upon  their  pathology. 

There  is,  however,  one  kind  of  solid  constituent  which  is  found 
almost  constantly  in  these  fluids,  viz:  the  crystals  of  various  salts: 
these  being,  however,  unorganized,  their  consideration  does  not  prop- 
erly belong  to  a  work  devoted  to  descriptions  and  delineations  of 
organized  tissues. 

It  is  proposed,  therefore,  in  order  to  render  the  application  of  the 
microscope  to  human  physiology  and  pathology  as  complete  as  possi- 
ble, to  prepare  a  separate  treatise  on  the  subject  of  the  crystallizations 
formed  in  the  various  fluids,  &c,  of  the  body,  under  the  title  of 
Human  Crystallography. 

We  will  now  pass  in  review  the  fluids  comprehended  in  the  division 
of  Unorganized  Fluids.  In  reference  to  some  of  them,  but  little 
remains  to  be  said,  as  will  have  been  inferred  from  a  knowledge  of 
their  structureless  character.  In  the  treatise  on  Crystallography, 
however,  many  interesting  and  important  details  will  be  given. 

The  Unorganized  Fluids  comprise  the  saliva,  the  bile,  the  sweat, 
the  urine,  and  the  gastric,  pancreatic,  and  lachrymal  fluids;  these 


THE      SALIVA, 


211 


several  fluids  especially  deserve  the  name  of  secretions,  since  they 
are  elaborated  by  large  and  complexly  organized  glands. 


THE    SALIVA. 


The  saliva  is  a  peculiar  fluid  secreted  by  the  parotid,  sub-maxillary 
and  sub-lingual  glands,  from  which  it  is  conveyed  by  certain  ducts 
into  the  mouth,  where  it  becomes  mingled  with  the  buccal  mucus. 
The  amount  of  saliva  secreted  during  the  day  is  estimated  at  from  ten 
to  twelve  ounces;  during  salivation,  either  spontaneous  or  induced 
by  mercury,  the  quantity  may  exceed  two  or  three  quarts.  It  is 
worthy  of  remark,  however,  that  in  these  latter  cases  the  mercury  has 
never  been  detected  in  the  saliva. 

Mitscherlich*  made  the  following  observations  on  a  person  having 
a  salivary  fistula,  and  in  whom  the  saliva  could  be  collected  directly 
as  it  flowed  from  Steno's  duct.  He  found  that  there  was  no  flow  of 
saliva  while  the  muscles  of  mastication  and  of  the  tongue  were  in 
complete  repose,  and  all  nervous  excitement  avoided.  He  observed, 
also,  that  during  the  acts  of  eating  and  drinking,  especially  at  the 
commencement,  the  secretion  was  most  abundant,  and  in  proportion 
to  the  stimulating  nature  of  the  food  and  the  degree  to  which  it  was 
masticated.  From  two  to  three  ounces  of  saliva  flowed  from  the 
duct  in  the  course  of  twenty- four  hours. 

The  solid  constituents  of  the  saliva  are  composed  of  fat,  ptyalin, 
watery  and  spirituous  extractive  matters,  a  little  albumen,  certain 
salts,  a  trace  of  sulphocyanogen,  mucous  corpuscles,  epithelial  scales, 
and,  lastly,  corpuscles  resembling  mucous  globules,  which  have  been 
termed  salivary  corpuscles,  and  which  are  probably  nothing  more 
than  epithelial  cells  in  progress  of  development. 

The  salts  of  human  saliva  are,  according  to  Mitscherlich,  chloride 
of  calcium,  lactates  of  soda  and  potash,  soda,  either  free  or  combined 
with  mucus,  phosphate  of  lime,  and  silica. 

In  certain  pathological  states  Simon  detected  in  the  saliva  acetic 
acid,  and  a  considerable  quantity  of  a  substance  resembling  caseine. 

The  saliva  is  with  difficulty  to  be  obtained  in  a  pure  state,  it  being 
generally  intermixed  with  a  greater  or  less  quantity  of  buccal  mucus ; 
now  the  normal  reaction  of  the  saliva  is  alkaline,  that  of  mucus  acid; 
it  therefore  follows,  the  fluids  in  question  being  thus  intermingled  in 
variable  proportions,  that  the  reaction  presented  by  the  fluid  obtained 
varies  according  to  the  relative  quantity  of  each  ingredient;  thus. 

*  Rust's  Magaz.  vol.  xl. 
16 


242  UNORGANIZED     FLUIDS. 

sometimes  the  saliva,  when  tested,  will  appear  to  be  acid,  alkaline,  or 
neuter,  and  the  same  will  be  the  case  with  the  buccal  mucus. 

The  true  reaction  of  the  saliva,  then,  can  be  ascertained  only  by 
obtaining  it  unmixed  with  the  mucus  of  the  mouth,  and  then  testing 
it;  this  may  be  effected  by  first  washing  the  mouth  with  water,  and 
then  applying  the  test-paper  to  the  saliva  as  it  flows  from  the  orifice 
of  its  ducts. 

The  fact  referred  to  of  the  admixture  of  the  two  fluids,  saliva  and 
mucus,  will  serve  to  explain  why  test-paper,  applied  to  the  upper 
surface  of  the  tongue,  exhibits  frequently  an  acid  reaction,  while  that 
placed  beneath  it  manifests  the  presence  of  an  alkaline  fluid. 

In  morbid  states  the  normal  reaction  of  the  saliva  may  undergo  a 
complete  change,  and  it  may  become  either  neuter  or  acid :  this 
alteration  has  been  especially  observed  to  occur  in  deranged  condi- 
tions of  the  stomach,  in  acute  rheumatism,  in  cases  of  salivation,  and, 
according  to  Donne\  in  pleuritis,  encephalitis,  intermittent  fevers, 
uterine  affections,  and  amenorrhea. 

Acid  saliva  doubtless  exerts  a  very  injurious  effect  upon  the  teeth. 

The  admixture  of  the  saliva  with  mucus  is  readily  shown  by  means 
of  the  microscope,  which  reveals  the  presence  of  mucous  epithelial 
scales  in  all  stages  of  their  development;  as  the  scales  found  in  the 
sweat  are  derived  from  the  desquamation  of  the  epidermis,  so  are 
those  of  the  saliva  and  mucus  from  that  of  the  epithelium. 

The  saliva,  as  well  as  the  sweat,  yields  on  evaporation  crystals  of 
the  various  salts  referred  to  in  the  analysis. 

Blood  corpuscles  are  sometimes  present  in  the  saliva  and  mucus; 
these  proceed  usually  from  the  gums. 

The  uses  of  the  saliva  in  the  animal  economy  are  classified  by  Dr. 
Wright  as  follow: 

Active. — 1.  To  stimulate  the  stomach  and  excite  it  to  activity  by 
contact.  2.  To  aid  the  digestion  of  food  by  a  specific  action  upon 
the  food  itself.  3.  To  neutralize  any  undue  acidity  of  the  stomach 
by  supplying  a  proportionate  alkali. 

Passive. — 1.  To  assist  the  sense  of  taste.  2.  To  favour  the 
expression  of  the  voice.  3.  To  clear  the  mucous  membrane  of  the 
mouth,  and  to  moderate  thirst. 


The  bile,  like  the  unorganized  fluid  already  described,  presents  but 
little  of  interest  to  the  microscopist  in  its  normal  state. 


THE     SWEAT.  243 

It  happens,  however,  occasionally,  when  it  has  been  retained  in  the 
gall-bladder  for  a  long  time,  in  consequence  of  which  it  has  become 
inspissated,  that  it  does  contain  solid  and  coloured  particles. 

These  particles  have  been  noticed  by  Scherer*  and  also  by  Dr.  H. 
Letheby  of  the  London  Hospital,  who  was  so  considerate  as  to  trans- 
mit, for  my  examination,  a  portion  of  inspissated  bile,  containing 
them,  as  also  plates  of  cholesterine,  in  great  numbers. 

The  bodies  in  question  consist  of  two  parts,  an  external  colourless 
investing  portion,  and  an  internal  coloured  and  granular  matter;  this 
disposition  of  the  colouring  matter  imparts  to  them  the  aspect  of 
"  pigment  cells,"  which,  in  fact,  Scherer  considers  them  to  be. 

There  are  but  three  kinds  of  cells,  which,  if  cells  at  all,  they  could 
be  by  any  possibility,  viz:  liver,  epithelial,  or  pigment  cells.  Now, 
they  are  certainly  neither  of  the  first  two  mentioned,  as  may  be 
inferred  from  the  dissimilarity  of  size,  appearance,  and  structure  with 
these;  and  they  are  as  surely  not  "pigment  cells,"  because  such 
structures  do  not  enter  into  the  organization  of  the  liver. 

It  is,  then,  conceived  that  these  cell-like  bodies  are  not  true  cells, 
but  are  to  be  regarded  as  masses  of  concrete  mucus,  enclosing  more 
or  less  biliary  colouring  matter;  the  great  differences  observed  in 
their  form,  size,  and  general  appearance,  are  all  opposed  to  the  notion 
of  their  being  definitely  organized  cells. 

The  meconium  of  infants  very  generally  contains  the  cell-like 
bodies  described,  together  with  intestinal  mucus,  cuneiform  epithelium, 
and  occasionlly  cholesterine  in  a  crystalline  form. 

THE    SWEAT. 

The  sudoriparous  glands,  distributed  over  the  whole  surface  of  the 
body,  constantly  secrete  a  very  considerable  quantity  of  watery 
fluid:  this  fluid  passes  off  usually  in  the  form  of  an  insensible  vapour; 
in  some  cases,  however,  as  under  high  external  temperature,  active 
exercise,  and  in  certain  stages  and  forms  of  disease,  it  collects  on  the 
skin  in  the  form  of  drops,  which,  in  drying  up,  deposit  their  solid 
constituents  over  the  whole  extent  of  the  cutaneous  surface :  it  is 
then  more  particularly  termed  sweat. 

Many  attempts  have  been  made  to  determine  the  amount  of  fluid 
passing  off  by  the  skin;  the  average  quantity,  according  to  Seguin 
amounts  to  about  twenty-nine  ounces  of  fluid,  the  maximum  to  five 

*  Unlersuchungen,  &c,  p.  103. 


244  UNORGANIZED     FLUIDS. 

pounds,  and  the  minimum  to  one  pound,  eleven  ounces,  and  four 
drachms. 

The  amount  of  solid  constituents  carried  off  with  the  fluid  is, 
comparatively,  very  small,  not  exceeding  in  the  twenty-four  hours 
seven  or  eight  scruples ;  the  remainder  being  merely  water,  retaining 
in  it  -carbonic  acid  and  nitrogen,  the  quantity  of  the  former  gas  being 
increased  by  vegetable  diet,  and  the  amount  of  the  latter  by  an 
animal  regimen. 

Simon  has  established  the  existence,  in  normal  sweat,  of — 

1.  Substances  soluble  in  ether:  traces  of  fat,  sometimes  including 
butyric  acid. 

2.  Substances  soluble  in  alcohol:  alcohol  extract,  free  lactic  or 
acetic  acid,  chloride  of  sodium,  lactates,  and  acetates  of  potash  and 
soda,  lactate  or  hydrochlorate  of  ammonia. 

3.  Substances  soluble  in  water :  water  extract,  phosphate  of  lime, 
and  occasionally  an  alkaline  sulphate. 

4.  Substances  insoluble  in  water:  desquamated  epithelium,  and, 
after  the  removal  of  the  free  lactic  acid  by  alcohol,  phosphate  of  lime 
with  a  little  peroxide  of  iron. 

The  quantity  of  fluid  exhaled  is  subject  to  very  great  variations; 
thus,  it  is  increased  by  a  dry  and  light  atmosphere,  while  it  is  dimin- 
ished by  a  damp  and  dense  condition  of  the  air.  It  is  at  its  minimum 
at  and  immediately  after  meals,  while  it  is  at  its  maximum  during  the 
actual  period  of  digestion.  The  cutaneous  perspiration  is  in  antago- 
nism with  the  urinary  secretion;  thus,  an  excessive  secretion  of 
urine  diminishes  that  of  the  skin,  and  a  diminution  of  the  activity  of 
the  kidneys  is  usually  followed  by  an  augmentation  of  that  of  the 
sudoriparous  glands. 

But  little  of  interest,  in  a  microscopic  point  of  view,  attaches  to 
this  fluid;  the  only  solid  organic  constituent  contained  in  it  being 
detached  scales  of  epidermis,  which  is  ever  undergoing  a  process  of 
destruction  and  renewal;  these  scales,  therefore,  do  not  form  part  of 
the  sweat,  but  become  mixed  up  with  it  in  a  secondary  manner. 

The  copious  formation  and  discharge  of  the  cutaneous  fluid  which 
occur  under  certain  circumstances,  thus  do  not  merely  afford  a  relief 
to  internal  organs,  but  serve,  also,  by  detaching  and  washing  away 
the  older  and  useless  cells,  to  cleanse  the  epidermis,  and  to  render  this 
more  efficient  as  an  evaporating  surface. 

The  crystals  formed  on  the  evaporation  of  the  sweat,  in  states  of 


THE     URINE.  215 

health  and  disease,  have  been  but  little  studied;  it  is  probable  that  a 
knowledge  of  them  would  lead  to  the  discovery  of  some  facts  of  interest. 

The  cutaneous  fluid,  it  is  known,  is  in  health  acid ;  there  are  some 
situations,  however,  in  which  it  is  constantly  alkaline,  as  in  the  axilke, 
about  the  genital  organs,  and  between  the  toes ;  this,  probably,  arises 
from  its  admixture  with  the  secretions  of  the  small  follicles  which 
are  situated  in  those  parts. 

The  sweat,  like  the  urine,  is  to  be  regarded  as  a  cleansing  fluid, 
the  system  being  through  it  relieved  of  certain  surplus  and  effete 
matters. 

The  pathology  of  the  sweat  is  but  little  known ;  albumen  has  been 
observed  in  it  by  Anselmino,  in  a  case  of  febris  rheumatica,  and 
Stark  states,  that  it  may  be  met  with  in  the  sweat  in  gastric,  putrid, 
and  hectic  diseases,  and  also  on  the  approach  of  death.  The  amount 
of  acetic  acid,  ammonia,  and  the  salts,  may  all  be  increased.  Uric 
acid  and  quinine  have  been  found  in  the  sweat,  the  latter  preparation 
being  of  course  at  the  time  administered  medicinally. 

THE    URINE. 

Few  fluids  have  been  more  studied  of  late  years  by  the  micro- 
scopist  than  the  urine;  this  has  arisen  from  the  elegance  of  form, 
variety  of  composition,  and  important  character  of  the  numerous 
crystalline  deposits  which  are  formed  in  it  in  states  of  health  and 
disease,  and  which  can  be  satisfactorily  determined  only  by  the  aid 
of  the  microscope. 

The  great  advantage  of  the  application  of  the  microscope  over 
that  of  chemical  tests  to  the  study  of  the  urine  is,  that  the  indications 
which  it  affords  are  not  merely  certain,  but  also  prompt  and  facile, 
while  the  results  obtained  through  the  agency  of  chemistry,  although 
not  less  certain,  are  often  tedious  and  difficult. 

The  description  of  the  various  crystals  formed  in  the  urine  is 
reserved  for  another  occasion ;  in  this  place  will  be  noticed  only  the 
organic  constituents  which  occur  in  normal  and  abnormal  urine. 

In  order  that  the  pathological  alterations  to  which  the  urine  is 
liable  may  be  more  clearly  understood,  it  will  be  advisable,  first,  to 
describe  the  appearance  and  the  constitution  of  healthy  urine. 

Healthy  urine,  when  first  passed,  is  a  limpid  fluid  of  an  amber 
colour,  emitting  a  peculiar  odour,  exhibiting  an  acid  reaction,  and 
having  a  specific  gravity  of  about  1011. 

Abandoned  to  itself,  it  soon  loses  its  limpidity,  becomes  troubled, 


246 


UNORGANIZED      FLUIDS 


and  putrefies  more  or  less  quickly,  according  to  its  chemical  consti- 
tution and  the  state  of  the  temperature. 

The  following  is  Berzelius'  analysis  of  healthy  urine,  and  with 
which  all  other  subsequent  analyses  have  been  found  to  agree  to  a 
very  considerable  extent:   1000  parts  contained — 


Water, 

- 

933  00 

Solid  residue, 

- 

67  00 

Urea, 

- 

30-10 

Uric  acid, 

- 

100 

Free  lactic  acid,  lactate  of 

ammonia 

alcohol 

and  water  extract, 

- 

1714 

Mucus, 

- 

0  32 

Sulphate  of  potash, 

- 

371^ 

Sulphate  of  soda, 

- 

316 

Phosphate  of  soda, 

- 

2  94 

Biphosphate  of  ammonia, 

- 

165 

Chloride  of  sodium, 

- 

4-45' 

Chloride  of  ammonium, 

- 

150 

Phosphate  of  lime  and  mag] 

lesia, 

100 

Silicic  acid, 

- 

0  03> 

Fixed 
L  salts, 
15  29. 


It  will  be  seen  from  the  above  analysis  that  healthy  urine  does  not 
contain  the  nitrogenized  principles  albumen,  fibrin,  or  caseine,  which 
are  encountered  so  frequently  in  urine  voided  in  disease. 

The  only  solid  organized  constituents  which  are  constantly  encoun- 
tered in  healthy  urine,  are  mucous  corpuscles  and  epithelial  scales; 
these  do  not  form  part  of  the  urine,  but  belong  to  the  structure  of 
the  mucous  membrane  of  the  bladder  and  urethra,  and  both  of  them 
may  be  detected  with  the  greatest  facility  by  the  microscope.  On 
account  of  their  greater  specific  gravity,  they  subside  at  the  bottom 
of  the  vessel  containing  the  urine,  where  they  may,  at  most  times,  be 
procured  for  examination. 

Occasionally,  however,  in  the  urine  of  man,  under  the  circum- 
stance already  referred  to  in  the  article  on  the  semen,  the  sperma- 
tozoa are  present  in  the  urine  also. 


PATHOLOGY    OF    THE    URINE. 


The  organic  principles  contained  in  diseased  urine  may  be  divided, 
firstly,  into  those  which  are  usually  encountered  in  that  fluid  in  a 


THE      URINE.  247 

state  of  solution,  but  which  do  yet,  under  certain  circumstances, 
assume  the  solid  form ;  and,  secondly,  into  those  which,  being  definite 
organisms,  occur  only  in  a  solid  condition.  Albumen,  fibrin,  caseine, 
and  fat,  belong  to  the  first,  and  the  blood  and  pus  corpuscles  to  the 
second  division. 

Albuminous  Urine. 

Albumen  is  frequently  present  in  the  urine  in  disease;  it  has  been 
noticed  to  occur  especially  in  Bright's  disease  of  the  kidney,  and  in 
the  urine  passed  after  scarlatina. 

If  the  albumen  be  present  in  any  considerable  quantity,  nitric  acid 
or  bichloride  of  mercury  will  cause  a  precipitate,  and  the  urine  will 
become  turbid  on  the  application  of  heat,  and  deposit  flocculi  of 
coagulated  albumen. 

The  colour,  specific  gravity,  and  reaction  of  albuminous  urine  are 
various ;  thus,  it  may  be  either  light  or  dark  coloured,  it  may  be  of 
high  or  low  specific  gravity,  it  may  exhibit  either  an  acid  or  an 
alkaline  reaction,  or  it  may  be  neutral. 

When  the  albumen  is  small  in  quantity,  heat  is  the  most  efficient 
test  for  its  detection;  it  is  only  when  the  urine  manifests  a  decided 
alkaline  reaction,  that  nitric  acid  is  preferable,  the  albumen  being 
held  in  solution  by  the  free  alkalies. 

Urine  may,  however,  become  turbid  from  the  application  of  heat, 
even  when  no  albumen  is  present ;  this  arises  from  precipitation  of 
the  earthy  carbonates;  in  these  instances,  the  addition  of  nitric  acid 
will  immediately  disperse  the  cloudiness,  and  the  reapplication  of  heat 
will  not  occasion  any  further  precipitation. 

Dr.  G.  O.  Rees  has  observed  that  the  urine  of  persons  who  have 
been  taking  cubebs  or  balsam  of  copaiba  is  rendered  turbid  by  nitric 
acid,  although  it  contains  no  albumen;  this  urine,  however,  is  not 
affected  by  heat. 

From  the  facts  contained  in  the  two  preceding  paragraphs,  it 
follows  that  a  precipitate  might  possibly  ensue  on  the  application 
of  heat,  and  by  the  addition  of  nitric  acid,  and  yet  no  albumen  be 
present  in  the  urine. 

If  the  precipitate  yielded  by  nitric  acid,  added  to  urine  impregnated 
with  the  active  principles  of  cubebs  or  copaiba,  be  examined  with  the 
microscope,  it  will  be  found  to  consist  of  minute  oil  bubbles,  which 
are  of  course  readily  soluble  in  ether. 


248  UNORGANIZED      FLUIDS, 


Fibrinous  Urine. 

Fibrin  has  been  encountered  in  the  urine  independently  of  the 
other  constituents  of  the  blood :  Zimmerman*  has  described  seven 
cases  of  fibrinous  urine. 

Such  urine,  if  the  fibrin  existed  in  it  in  any  quantity,  would 
coagulate  or  form  a  clot. 

It  is  necessary  in  these  cases  not  to  confound  mucus  with  fibrin ; 
the  former,  under  the  microscope,  exhibits  the  well-known  mucous 
corpuscles,  while  the  latter  appears  either  filamentous  or  simply 
granular. 

Fatty  Urine. 

The  urine  may  contain  fat,  either  separately  or  conjointly  with 
albumen,  or  with  caseine,  and  probably  also  sugar:  the  urine  holding 
fat  in  a  free  state  may  be  called  fatty ;  that  in  combination  with 
albumen,  chylous ;  and  lastly,  the  urine  in  which  fat  occurs  in  con- 
nexion with  caseine  and  sugar  may  be  denominated  milky  urine. 

Fatty  urine  has  been  observed  to  occur  frequently  in  persons  labour- 
ing under  phthisis;  the  fat,  as  the  liquid  cools,  forming  a  thin  pellicle 
on  its  surface,  the  nature  of  which  may  be  at  once  ascertained  by  the 
microscope,  which,  if  it  be  really  fatty,  will  reveal  the  presence  of 
innumerable  fat  globules. 

Cases  have  been  recorded  in  which  the  quantity  of  fat  has  been  so 
considerable  that  it  could  be  detected  with  the  naked  eye. 

Chylous   Urine. 

Chylous  urine  is  a  white  semi-opaque  fluid,  and  contains  both  fat 
and  albumen;  the  former  may  be  detected  by  means  of  the  micro- 
scope, and  the  latter  will  be  coagulated  by  heat,  by  nitric  acid,  and 
the  bichloride  of  mercury.  Examined  microscopically,  the  coagu- 
lated albumen  exhibits  a  granular  texture. 

This  form  of  urine  has  been  observed  principally  in  cases  of  gout. 

Milky  Urine. 
True  milky  urine  is  of  very  rare  occurrence,  there  being  but  two 
or  three  well-authenticated  cases  of  it  recorded;  urine  containing  the 
constituents   of  chyle   having   doubtless   been   described,  in   many 
instances  as  milky  urine. 

*  Zur  Analysis  und  Sunthesis  der  pseudoplastischen  Prozesse,  Berlin,  1844,  p.  129. 


THE     URINE.  249 

The  fat  in  milky  urine  occurs  in  combination  with  caseine,  and 
probably  with  sugar  also. 

The  fatty  constituent  may  be  detected  as  in  the  previously-decribed 
urines,  the  fatty  and  the  chylous,  by  means  of  the  microscope,  and  the 
caserne  will  be  precipitated  by  the  addition  of  a  little  acetic,  dilute 
sulphuric,  or  hydrochloric  acid,  the  flocculi  of  which,  examined  micro- 
scopically, will  exhibit  a  granular,  and  even  in  many  cases  a  globular  con- 
stitution ;  they  will  contain  also  a  greater  or  less  number  of  fat  globules. 

Urine  containing  caseine  in  solution  may  be  distinguished  from 
albuminous  urine  by  the  application  of  heat,  which  in  the  latter  will 
occasion  a  precipitate,  none  being  formed  in  the  former,  unless,  indeed, 
a  considerable  quantity  of  nitric  acid  be  also  present  in  the  urine, 
when  a  temperature  of  104°  Fah.  will  be  sufficient  to  occasion  the 
precipitation  of  the  caseine. 

It  is  not  to  be  supposed,  by  the  use  of  the  term  milky  urine,  that 
the  milk,  as  such,  ever  exists  in  the  urine,  and  that  it  finds  its  way 
there  from  the  mammary  gland  by  metastasis;  the  utmost  that  is  to 
be  inferred,  from  the  existence  of  the  principal  elements  of  milk  in  the 
urine,  is,  that  the  kidney,  in  place  of  the  mammary  gland,  has  sepa- 
rated those  elements  from  the  blood. 

Excess  of  Mucus  in  the  Urine. 

In  catarrhus  vesica,  an  affection  to  which  old  persons  are  particu- 
larly liable,  mucus  is  secreted  in  considerable  quantities,  and  is  voided 
with  the  urine. 

This  mucus  subsides  to  the  bottom  of  the  vessel,  is  semi-opaque, 
thick,  and  ropy;  examined  with  the  microscope,  mucous  corpuscles 
and  epithelial  scales  are  encountered  in  it. 

In  those  cases  in  which  the  urine  is  very  alkaline,  the  mucus  is 
observed  to  be  particularly  tenacious  and  thready;  this  condition 
results  from  the  action  of  the  free  alkalies  contained  in  the  urine  upon 
the  constitution  of  the  mucus. 

Blood  in  the  Urine. 
Blood  is  frequently  contained  in  the  urine,  and  voided  with  it;  thus, 
it  is  frequently  encountered,  in  greater  or  less  quantity,  in  the  follow- 
ing cases :  in  inflammation  of  the  kidneys,  in  injui'ies  of  those  organs, 
or  of  the  bladder  itself,  in  cases  of  stricture  from  the  introduction  of  a 
catheter,  from  the  passage  of  renal  or  urinary  calculi,  and,  lastly,  from 
chronic  disease  of  the  kidneys  and  bladder. 


250  UNORGANIZED      FLUIDS. 

The  best  test  of  the  existence  of  the  blood  in  the  urine  is  the 
detection  of  the  blood  corpuscles  by  the  microscope ;  blood,  however, 
may  exist  in  the  urine,  and  yet  no  corpuscles  be  detected,  these  having 
been  dissolved  by  the  acids  of  the  urine.  Failing,  however,  to  detect 
the  blood  discs,  if  blood  really  be  present,  then  the  albumen,  fibrin, 
and  hematin  will  still  remain,  and  may  be  distinguished  by  suitable 
reagents. 

From  the  colour  of  urine,  no  conclusion  can  be  formed  as  to  the 
existence  of  blood  in  it,  as  urine  of  a  deep  blood-colour  is  some- 
times met  with,  which  on  examination  is  found  not4o  contain  any 
trace  of  blood. 

Pus  in  the  Urine. 

It  has  already  been  stated  in  these  pages  that  no  absolute  distinction 
exists  between  mucus  and  pus;  and,  therefore,  it  follows  that  it  is  in 
most  cases  impossible  to  determine,  with  any  degree  of  certainty, 
whether  pus  exists  in  the  urine  or  not. 

If,  however,  the  sediment  rendered  with  the  urine  want  the  tenacity 
of  vesical  mucus,  and  contain  the  granular  corpuscles  common  to 
mucus  and  pus,  there  is  reason  to  suspect  that  the  fluid  in  question  is 
really  purulent. 

The  diagnosis  will,  however,  be  greatly  assisted  by  reference  to  the 
history  and  symptoms  of  the  case ;  thus,  if  there  be  rigors  and  hectic 
fever,  the  probability  of  the  existence  of  pus  will  be  much  strengthened. 

There  is  one  circumstance  which  requires  to  be  mentioned,  and 
which  greatly  increases  the  difficulty  of  discrimination  between  mucus 
and  pus.  In  some  cases  of  purulent  urinary  deposits,  the  urine  is 
alkaline;  now,  the  effect  of  the  action  of  alkalies  on  pus  is  to  convert 
it  into  a  transparent  and  tenacious  substance  in  every  respect  resem- 
bling mucus,  and  which,  therefore,  cannot  be  distinguished  from  it. 

There  are  but  few  details  interesting  to  the  microscopist  connected 
with  the  Gastric,  the  Pancreatic,  and  the  Lachrymal  fluids;  it  will, 
therefore,  be  unnecessary  to  treat  of  them  at  any  length.  It  is  to  the 
chemist  and  physiologist  chiefly  that  the  gastric  fluid  is  interesting. 
They  all,  however,  but  especially  the  gastric  and  the  lachrymal  secre- 
tions, contain  mucous  corpuscles  and  epithelial  scales,  derived  from 
the  desquamation  of  the  epithelium  of  the  surfaces  by  which  they  are 
secreted,  and  over  which  they  pass. 


THE     URINE.  251 

Obs. — At  page  135,  the  opinion  is  attributed  to  Mr.  Addison,  that 
the  white  corpuscles  of  blood,  mucus,  and  pus  contain  filaments; 
whereas  it  would  appear,  from  a  closer  examination  of  the  text,  that 
the  statement  of  that  gentleman  only  goes  to  the  extent  of  asserting, 
that'  the  fluid  enclosed  in  those  corpuscles  resolves  itself  in  its  escape 
into  the  filaments,  of  which  the  fibrinous  portions  of  blood,  mucus,  and 
pus  are  under  certain  circumstances  observed  to  be  constituted. 


252  UNORGANIZED     FLUIDS. 

URINE. 

[In  the  pathology  of  the  urine,  the  microscope  has  now  become  of  equal 
value  with  chemistry ;  a  proper  consideration  of  this  whole  subject  would 
require  a  volume  of  the  size  of  the  present  one,  and  therefore  it  is  not  here 
attempted.  For  reference  on  this  subject,  especially  on  the  microscopical 
characters  of  urine,  the  student  may  consult  "Simon's  Chemistry  of  Man," 
"  Bird  on  Urinary  Deposits ;"  "  Practical  Manual  on  the  Blood,"  by  John  Wm. 
Griffith;  "On  the  Analysis  of  the  Blood  and  Urine,"  by  G.  Owen  Rees; 
"A  Guide  to  the  Examination  of  Urine,"  by  Alfred  Markwick;  "Frick  on 
Renal  Diseases;"  "Prout  on  do." 

Those  who  wish  to  study  the  pathology  of  the  urine,  with  the  microscope, 
will  find  the  following  hints  useful.  After  allowing  the  urine  to  stand  for  a 
little  time,  more  or  less  sediment  will  take  place.  This  is  to  be  drawn  up 
by  means  of  a  pipette,  and  a  drop  placed  on  a  plain  glass  slide,  and  covered 
with  thin  glass.  It  is  then  ready  for  examination,  first  with  a  one-fourth 
inch  object-glass,  and  afterward  with  a  one-eighth.  This  high  power  is 
necessary  to  recognise  the  presence  of  blood,  mucus,  or  pus  corpuscles,  or 
the  minute  crystals  of  oxalate  of  lime. 

When  the  presence  of  an  undue  quantity  of  lithate  of  ammonia  is  sus- 
pected, the  test-tube  or  other  glass  vessel  containing  the  urine  must  be 
heated  gently,  when  the  supernatant  fluid,  with  the  lithate,  may  be  poured 
off",  or  removed  with  a  pipette.  Most  of  the  urinary  sediments  can  be  well 
preserved ;  the  most  transparent,  such  as  oxalate  of  lime,  &c,  are  best 
mounted  in  fluid.  For  this  they  are  prepared  by  being  repeatedly  washed 
in  distilled  water,  until  all  trace  of  gummy  matter,  so  often  combined  with 
urinary  deposits,  is  removed.  They  are  then  placed  on  a  plain  glass  slide, 
or  in  a  thin  glass  cell,  mixed  with  a  little  water  by  means  of  a  pipette,  and 
the  water  allowed  to  evaporate.  A  drop  or  two  of  alcohol  and  water,  of 
Goadby's  solution,  or  of  the  creosote-water,  is  to  be  added,  and  the  thin  glass 
cover  applied  and  cemented  with  gold  size,  care  being  taken  that  no  air- 
bubbles  are  present. 

Other  urinary  deposits,  requiring  to  be  rendered  more  transparent,  are 
best  preserved  in  Canada  balsam.  The  deposit  must  be  well  washed  as 
before,  and  after  being  placed  on  the  glass  slide,  and  the  water  allowed  to 
evaporate,  must  be  mounted  in  balsam  with  heat,  as  directed  in  the  chapter 
on  the  Preservation  of  Objects.  Certain  deposits  are  best  preserved  in  the 
dry  way,  such  as  uric  acid,  &c. 

Other  sediments,  and  these  are  chiefly  salts,  are  best  mounted  in  syrup, 
made  thick,  and  mixed  with  a  little  gum.  This  is  to  be  used  in  the  same 
way  as  the  balsam  without  heat,  and  the  sediment  deposited  in  the  thin 
glass  cell,  or  that  made  with  asphaltum  or  other  cement.  Castor  oil  has 
been  successfully  used  as  a  medium  for  mounting  urinary  deposits.  In  this 
method,  no  heat  is  necessary.] 


PART    II.  — THE     SOLIDS. 


The  division  of  the  various  constituents  of  the  animal  fabric  into 
the  two  orders  of  Fluids  and  Solids,  although  a  very  ancient  one, 
is  yet,  to  a  certain  extent,  arbitrary  and  artificial.  The  truth  of  this 
observation  is  rendered  apparent  on  reference  to  the  several  fluids, 
the  description  of  which  has  just  been  brought  to  a  conclusion,  and 
all  of  which  contain  suspended  in  them,  either  as  essential  or  as 
accessory  elements,  various  solid  and  organized  particles :  the  liquid 
portion  of  some  of  these  compound  fluids  exhibiting  also  a  distinctly 
organized  constitution;  as,  for  example,  the  liquor  sanguinis  and  the 
fluid  parts  of  mucus  and  of  pus. 

The  distinction  referred  to  is  not,  however,  without  its  use,  and  is 
sufficiently  well  founded  to  serve  the  purposes  of  classification. 

Of  the  Solids  themselves  it  is  unnecessary  to  make  any  formal  sub- 
divisions :  they  will  simply  be  treated  of  in  the  order  of  their  natural 
relationship  with  each  other. 

Thus,  the  various  solid  structures  entering  into  the  constitution  of 
the  animal  organism  will  be  described  consecutively  as  follows,  each 
forming  the  subject  of  a  distinct  article :  Fat,  Epithelium,  Epidermis, 
Pigment  Cells,  Nails,  Hair,  Cartilage,  Bone,  and  Teeth;  the  vari- 
ous Tissues,  the  Cellular,  under  which  head  Ligaments  and  Tendons 
will  be  described,  the  Elastic,  the  Muscular,  and  the  Nervous, 
including  the  description  of  the  Brain  and  Nerves ;  the  Glands,  Ves- 
sels, Membranes ;  and,  lastly,  the  Pathology  of  the  Solids,  will  be 
treated  of. 


254  THE     SOLIDS. 


ART.   VIII.  — FAT. 

The  transition  from  the  fluids  to  the  solids  would  appear  to  be  a 
very  easy  and  natural  one  through  the  substance  about  to  be  described : 
thus,  fat  bears  an  evident  relation  to  both  the  former  and  the  latter, 
remaining  during  life  in  a  soft  and  semi-fluid  state,  and  after  death 
becoming  hard  and  solitl;  it  is,  however,  to  the  milk  globules  among 
the  fluids  that  it  manifests  the  closest  affinity,  the  fat  vesicles,  espe- 
cially those  of  early  life,  and  the  milk  globules  resembling  each  other 
in  form,  in  appearance,  and  in  the  manner  in  which  reagents  act 
upon  them. 

Fat  is  made  up  of  the  aggregation  of  a  number  of  globules  or  ves- 
icles, which  some  deem  to  be  true  cells,  and  which  are  held  in  juxta- 
position by  intersecting  bands  of  cellular  tissue;  these  vesicles,  have 
a  smooth  surface,  semi-opaque  texture,  and  they  reflect  the  light  in 
the  strongest  manner. 

Contents. — The  contents  of  fat  vesicles  usually  present  a  homoge- 
neous appearance;  sometimes  nevertheless — as  when  undergoing 
decomposition,  and  when  they  have  been  subjected  to  pressure — they 
exhibit  a  granular  aspect ;  these  contents  are  of  an  oily  nature,  and 
chemists  have  detected  in  the  lard  of  the  pig  the  organic  products, 
oleine,  stearine,  margaric  acid,  a  yellow  colouring  matter  having  the 
odour  and  the  nauseous  taste  of  bile,  and  the  chemical  salts,  chloride 
of  sodium,  acetate  of  soda,  and  traces  of  carbonate  of  lime  and  oxide 
of  iron.  It  is  probable  that  of  these  constituents  the  presence  of  the 
chloride  of  sodium  depended  on  the  mode  of  preparation  of  the  lard. 

Form. — The  form  presented  by  the  fat  vesicles  is  various,  but  is 
usually  either  globular,  oval,  or  polygonal.  The  first  shape  is  encoun- 
tered in  the  fat  of  young  animals  especially  (see  Plate  XVIII.  fig.  1); 
the  second  in  that  of  adults  (see  fig.  2);  and  the  third  in  situations 
where  the  fat  is  subjected  to  considerable  pressure,  and  on  solidifica- 
tion after  death.  The  fat  vesicles  of  the  pig  are  described  as  being 
elongated  and  kidney-shaped.  This  shape,  however,  is  of  rare  occur- 
rence, and  cannot  be  regarded  as  the  ordinary  and  characteristic  form, 
which  is  most  generally  more  or  less  spherical  or  oval.  Raspail, 
observing  this  exceptional  form,  was  led  to  institute  from  it  an  erro- 
neous comparison  between  fat  vesicles  in  general  and  the  starch 
granule. 


FAT.  255 

Size. — The  fat  vesicles  of  the  adult  are  usually  several  times  larger 
than  the  solid  corpuscles  of  any  of  the  fluids  described — the  blood, 
mucus,  and  milk;  the  size  of  the  fat  vesicles  in  any  given  quantity 
of  fat  is  not  uniform ;  but,  like  the  globules  of  milk,  varies  exceedingly, 
the  dimensions  of  the  larger  vesicles  surpassing  several  times  those 
of  the  smaller. 

One  exceedingly  interesting  law  has  been  observed  in  reference  to 
the  size  of  fat  vesicles;  thus,  it  has  been  ascertained  that  their 
average  magnitude  increases  from  infancy  up  to  adult  age :  in  accord- 
ance with  this  law,  the  fat  cells  of  an  infant  will  be  found  to  be 
several  times  smaller  than  those  of  a  full-grown  person,  and  those  of 
a  child  again  of  an  intermediate  size.  This  law  will  be  apparent  from 
an  examination  of  the  figures  given.     (See  Plate  XVIII.) 

Colour. — The  colour  of  fat  is  subject  to  considerable  variations, 
but  it  usually  exhibits  a  tinge,  more  or  less  deep,  of  yellow.  The  fat 
of  young  animals  is  usually  of  a  lighter  colour  than  that  of  the  full- 
grown  and  aged;  this  may  be  seen  by  a  comparison  of  the  fat  of  an 
infant  with  that  of  an  adult,  or  of  the  fat  of  the  calf  with  that  of  the 
ox;  in  the  former  it  is  almost  white,  while  in  the  latter  it  frequently 
exhibits  a  deep  and  golden  hue.  The  differences  of  colour  referred  to 
doubtless  denote  differences  in  the  relative  proportion  of  the  different, 
constituents  of  fat. 

In  some  animals,  also,  fat  of  various  bright  colours  is  encountered, 
especially  in  Birds,  beneath  the  skin  of  the  beak  and  of  the  feet;  in 
the  Crustaceae  and  in  some  of  the  Reptilia.  In  the  Triton,  the  fat  is 
of  a  deep  orange-colour,  approaching  to  red.  The  coloration  of  the 
iris  of  birds  depends,  according  to  Wagner,  upon  a  fat  which  is 
accumulated  in  drops,  and  perhaps  also  in  cells. 

Consistence. — The  consistence  of  fat  is  different  in  different 
animals,  and  also  varies  in  accordance  with  the  temperature;  thus, 
the  fat  of  the  pig  is  softer  than  that  of  the  ox  or  sheep;  that  of  the 
human  subject  is  intermediate  between  both  in  its  consistence,  and 
all  kinds  of  fat  are  harder  in  cold  than  in  warm  weather.  The  varia- 
tion in  the  solidity  of  fats  depends  upon  the  amount  of  stearine  and 
oleine  which  they  contain ;  the  hard  fats  containing  a  greater  quantity 
of  stearine  than  the  soft  fats,  in  which  the  oleine  is  greatest. 

Structure. — Most  observers  agree  in  assigning  to  each  fat  vesicle 
a  distinct  investing  membrane,  notwithstanding  which  fact  the  proofs 
adduced  by  them  of  the  existence  of  such  a  structure  are  by  no 
means  so  decisive  as  to  render  such  a  conclusion  any  thing  more 


256  THE     SOLIDS. 

than  doubtful:  thus,  micrographers,  hitherto,  have  been  unable  to 
demonstrate  the  presence  around  normal  fat  vesicles  of  an  enveloping 
tunic,  but  have  been  contented  to  rest  their  opinion  upon  the  indirect 
and  uncertain  evidence  to  be  derived  from  a  knowledge  of  the  action 
of  reagents ;  upon  testimony,  in  fact,  analogous  to  that  upon  which 
Henle  and  Mandl  decided  in  favour  of  the  existence  of  a  membrane 
surrounding  the  milk  globule. 

Schwann,  indeed,  states  that  he  found  the  membrane  of  the  fat  cell 
to  be  almost  as  thick  as  the  blood  globule  of  man  in  an  infant  affected 
with  mollities  ossium* 

Henle  also  has  observed  around  the  obscure  periphery  of  a  fat  cell 
a  strait  and  clear  band,  but  could  not  assure  himself  that  this  was 
not  the  result  of  an  optical  illusion. f 

The  above  are  the  only  trustworthy  observations  of  a  direct  char- 
acter recorded  in  proof  of  the  existence  of  a  distinct  tunic  to  the  fat 
vesicle,  and  they  are  evidently  not  of  a  satisfactory  or  decisive  nature. 

The  indirect  testimony  procured  from  a  knowledge  of  the  action  of 
reagents  is  as  follows:  Ether  is  stated  to  render  the  contents  of  the 
fat  vesicle  fluid  and  transparent,  without,  at  the  same  time,  diminishing 
its  size,  as  is  proved  by  the  fact  that  on  the  resolidification  of  its 
contents,  the  vesicle  presents  the  same  form  and  dimensions  as  at  first. 

Again,  acetic  acid,  according  to  Henle,  acts  upon  the  fat  vesicle 
as  upon  the  milk  globule,  destroying  the  membrane  in  different  places ; 
it  permits  the  escape  of  a  number  of  globules  of  oil  or  grease,  which, 
like  pearl-drops,  remain  attached  to  the  larger  vesicle. 

Ether,  however,  produces  other  effects  than  those  usually  described, 
and  which  are  mentioned  above;  thus,  when  applied  to  the  fat 
vesicles  of  the  pig,  many  of  them  will  be  seen  to  burst,  and  to  collapse 
frequently  to  less  than  the  fourth  of  their  original  size,  losing,  at  the 
same  time,  all  definite  form ;  and,  in  proportion  as  the  vesicle  collapses, 
one  large  circular  drop,  or  two  or  three  smaller  ones,  will  be  seen 
gradually  to  form  around  and  envelope  the  shrunken  vesicle,  which 
is,  however,  never  entirely  dissolved. 

There  are  other  observers  again,  as  Schwann  and  Henle,  who 
consider  that  fat  vesicles  are  not  merely  provided  with  an  envelope, 
but  that  they  are  true  cells,  possessing  both  cell  wall  and  nucleus. 

Thus,  Schwann  noticed  in  the  wall  of  the  fat  vesicles  of  the  child 
already  referred  to,  a  nucleus  of  round  or  oval  form,  sometimes 
flattened,  and  sometimes  not  so. 

*  Mikroskopische  Untersuchungen,  p.  140,  f  Anal.  Gen.  p.  422. 


FAT.  257 

Furthermore,  Henle  writes,  "very  frequently  the  wall  presents  a 
salient  point  on  some  part  of  its  extent,  and  in  that  position  exists  a 
nucleus,  or  a  trace  of  a  nucleus.  Sometimes  there  are  two  nuclei, 
and  in  very  many  cases  they  cannot  be  observed  at  all."* 

Again,  Mandl  has  made  the  observation  in  examining  the  fat  tissue 
of  young  rabbits,  and  especially  in  taking  the  little  masses  of  fat 
which  lie  along  the  vertebral  column  in  the  interior  of  the  pectoral 
cavity,  that  the  vesicles  appear  but  half  filled,  and  that  they  consist  of 
two  parts,  an  inner  one  conveying  the  aspect  of  a  drop  of  oil,  and  an 
outer  membranous  portion,  f 

Such  are  the  facts  hitherto  recorded  in  favour  of  the  presence  of  a 
nucleus  in  the  fat  vesicle:  it  will  be  seen  that  although  they  are  more 
definite  and  satisfactory  than  those  adduced  in  proof  of  the  existence 
of  an  investing  membrane,  yet  that  they  are  scarcely  in  themselves 
sufficient  to  set  at  rest  the  question  of  its  cellular  nature. 

The  observations,  then,  cited  above,  while  they  fail  to  demonstrate 
sufficiently  the  true  organization  of  the  fat  vesicle,  yet  render  it 
extremely  probable  that  it  is  really  cellular.  In  favour  of  this  view, 
a  few  additional  observations  have  occurred  to  myself,  which  are 
conclusive  on  one  of  the  two  debated  points  of  the  organization  of 
the  fat  vesicle.  The  first  have  reference  to  the  outer  membrane.  If 
a  thin  slice  of  any  of  the  softer  fats  placed  between  two  plates  of 
glass  be  pressed  firmly,  though  not  with  too  great  violence,  and 
subsequently  be  examined  with  the  microscope,  it  will  be  seen  that 
the  vesicles  have  not  run  into  each  other,  but  still  preserve  their 
individuality. 

Again,  ether  applied  to  the  fat  vesicle  does  not  entirely  dissolve  it ; 
even  when  it  causes  it  to  burst  and  collapse,  a  residue  always  remains, 
and  this  probably  is  membranous. 

Furthermore,  if  a  thin  slice  of  fat  be  placed  between  two  plates  of 
glass,  and  having  been  forcibly  compressed,  be  examined  with  the 
microscope,  it  will  be  seen  that  some  of  the  vesicles  have  burst, 
discharging  a  portion  of  their  contents,  the  membrane  of  the  fat 
vesicle  then  becoming  visible,  and  declaring  its  existence  by  certain 
folds  and  markings,  into  which  it  falls  on  the  escape  of  its  contents, 
and  by  the  jagged  outline  of  the  rent  through  which  those  contents 
passed.     (See  Plate  XIX.  jig.  2.) 

Finally,  decomposition  produces  an  effect  somewhat  analogous  to 
that  occasioned  by  pressure;  the  fat  vesicles  burst,  and  their  fluid 

*  Anal.  Gen.  p.  422.  f  Anaiomie  Microscopique,  p.  141. 

17 


258  THE     SOLIDS. 

contents  escape,  leaving  the  membrane  in  most  cases  entirely  empty, 
and  which,  as  well  the  aperture  in  its  parietes,  may  be  easily  detected 
with  the  microscope ;  the  soft  contents  of  the  vesicles  break  up,  and 
resolve  themselves  into  globules  of  an  oil-like  appearance.  (See 
Plate  XIX.  fig.  4.) 

The  second  set  of  observations  relate  to  the  nucleus. 
If  a  thin  slice  of  the  fat  of  the  pig  be  pressed  as  before  between 
two  slips  of  glass  with  a  moderate  degree  of  pressure,  and  then  be 
submitted  to  the  microscope,  in  very  many  of  the  cells  will  be  seen 
a  dark  nucleus-like  body-  This  experiment  will  not,  however,  always 
succeed.     (See  Plate  XIX.  j%.  1.) 

A  body  of  a  similar  description,  but  of  a  more  defined  form,  is  very 
frequently  encountered  in  the  decomposing  cells  of  marrow  fat;  this 
nucleated  condition  of  the  cells  preceding  their  rupture.  (See  Plate 
XIX.  fig.  3.) 

Again,  in  some  fat  cells  contained  in  a  small  encysted  tumour 
removed  from  over  the  nasal  bones,  and  kindly  sent,  to  me  for 
examination  by  W.  H.  Ransom,  Esq.,  of  University  College  Hospital, 
(to  whose  zeal  and  intelligence  I  am  indebted  for  many  interest- 
ing specimens  of  morbid  structure,)  nucleoid  bodies  were  distinctly 
visible  even  without  pressure,  although  they  became  more  apparent 
after  a  gentle  degree  of  compression  had  been  applied.  (See  Plate 
XIX.  fig.  6.)  The  apparent  nuclei  in  the  cases  related  differed  from 
each  other  somewhat,  being  more  defined  and  darker  in  the  two 
latter  than  in  the  former;  the  cells  themselves  too  were  not  identical 
in  appearance ;  thus,  the  margins  of  those  of  the  pig  and  of  the 
human  marrow  fat  were  smooth  and  distinctly  defined,  while  those  from 
the  tumour  were  less  regular  and  distinct.  (See  Plate  XIX.  figs.  1 . 3. 6.) 
Now  these  nucleus-like  bodies  in  the  several  cases  mentioned, 
although  occupying  the  position  of  nuclei  and  presenting  the  appear- 
ance of  such,  it  is  very  possible  were  not  in  reality  true  nuclei;  it 
seems  to  me  that  their  formation  might  be  accounted  for  without  any 
reference  to  a  nucleus.  Thus  with  respect  to  the  nucleod  bodies  in 
the  cells  of  the  pig  produced  by  pressure,  their  formation  might  be 
explained  as  follows :  the  mutual  compression  of  the  fat  vesicles  upon 
each  other  would  tend  to  occasion  a  condensation  of  the  semi-fluid 
contents  in  the  centre  of  each,  and  in  this  way  the  appearance  of 
nuclei  would  be  produced. 

Again,  the  semblance  of  a  nucleus  in  the  decomposing  cells  might 
be  supposed  to  depend  upon  the  partial  escape  by  endosmosis  of  the 


FAT.  259 

contents  of  those  cells,  the  portion  remaining  in  them  representing  a 
nucleus  merely  from  the  position  occupied  by  it  in  the  centre  of  the  cells. 

The  formation  of  the  nucleated  bodies  in  the  third  case  would  seem 
to  point  to  and  to  require  a  different  explanation.  Decomposing  fat 
frequently  exhibits  a  crystalline  arrangement;  now,  it  is  conceived 
that  the  outer  part  of  each  vesicle  had  become  softened  and  broken 
down,  in  consequence  of  commencing  decomposition  or  of  disease, 
preparatory  to  its  assuming  the  crystalline  form,  the  central  part  at 
the  same  time  remaining  unaffected. 

It  will  be  seen  that  the  preceding  observations,  in  relation  to  the 
presence  of  a  nucleus  in  fat  vesicles,  are  not  decisive,  although  they 
add  weight  to  those  of  anterior  observers,  and  render  it  still  more 
probable  that  they  are  really  nucleated  cells. 

The  facts  adduced,  however,  in  reference  to  the  existence  of  an 
investing  membrane  are  quite  conclusive. 

On  the  vesicles  of  decomposing  human  fat,  it  is  a  common  occur- 
rence to  meet  with  stelliform  figures,  each  being  composed  of  a 
number  of  delicate  striae  radiating  from  a  central  point.  On  the 
smaller  vesicles  but  a  single  figure  of  this  description  will  usually  be 
met  with,  but  on  the  larger  there  may  be  three  or  four.  When  but 
one  is  present,  it  usually  covers  about  a  third  of  the  surface  of  each 
vesicle.     (See  Plate  XIX.  fig.  5.) 

Henle*  observes  of  these  that  they  might  be  metamorphoses  of  the 
nuclei  of  the  cells;  "nevertheless,"  he  says,  "they  have  more  analogy 
with  crystalline  deposits." 

The  occurrence  of  two,  three,  or  four  of  these  on  the  same  cell  is 
opposed  to  the  idea  of  their  connexion  with  the  nuclei;  and  the 
observation  of  Mandl,  who  noticed  their  formation  on  butter,  is  con- 
clusive on  this  point.f 

Vogel,J  as  also  Gerber,§  regard  the  figures  in  question  as  groups 
of  crystals  of  margaric  acid. 

Distribution. — The  fat  vesicles  are  distributed  in  groups,  which  lie 
near  to  and  follow  the  course  of  the  blood-vessels.  (See  Plate  XVIII. 
fig.  1.)  This  arrangement  is  particularly  evident  in  the  mesentery 
and  omentum,  and  may  be  compared  to  that  of  a  bunch  of  grapes,  the 
fat  vesicles  representing  the  grapes,  and  the  vessels  the  stalks  of  the 
bunch:  in  one  particular  only  does  the  comparison  fail;  thus,  each 

*  Loc.  cit.  p.  423.  f  Anat.  Mia,  f.  143. 

%  Arileilung  zum  Gebrauche  des  Mickroskops,  p.  289.  tab.  111.  fig.  2. 

§  Gerber's  General  Anatomy,  translated  by  Gulliver. 


280  THE     SOLIDS. 

grape  of  the  bunch  receives  and  is  attached  to  a  separate  pedicle, 
which  is  not  the  case  with  the  fat  vesicles,  although  one  observer  has 
asserted  that  a  separate  vessel  is  distributed  to  each  vesicle.  The  groups 
of  fat  vesicles  occurring  in  young  animals,  in  which  each  globule  is 
circular,  may  be  compared  to  heaps  of  shot  piled  up  upon  each  other. 

In  those  situations  in  which  the  fat  occurs  in  thick  and  dense  masses, 
the  arrangement  referred  to  is-  somewhat  different.  The  fat  vesicles 
are  still  parcelled  out  into  groups  by  means  of  intersecting  cellular 
bands ;  but  the  several  groups  lie  in  close  contiguity,  instead  of  being, 
as  in  the  former  case,  separated  from  each  other  by  distinct  intervals. 
Thi'oughout  these  masses,  too,  but  few  blood-vessels  are  distributed. 

The  intimate  arrangement  of  the  fat  vesicles  having  been  thus 
briefly  sketched,  it  remains  to  describe  the  general  distribution  of  fat 
throughout  the  body. 

In  man,  fat  is  developed  principally  in  the  loose  cellular  tissue ;  it 
is  encountered  forming  a  layer  of  variable  thickness  in  that  which  is 
situated  immediately  beneath  the  skin;  in  the  serous  membranes,  as 
in  the  omenta,  the  mesenteries,  and  the  epiploa;  on  the  surface  of 
the  heart,  and  around  the  kidney. 

In  certain  situations  the  sub-cutaneous  fatty  layer  experiences  an 
increased  development  designed  to  fulfil  certain  peculiar  intentions; 
thus,  in  the  soles  of  the  feet,  the  palms  of  the  hands,  in  the  female 
breast,  in  the  region  of  the  pubis,  and  over  the  glutei  muscles,  espe- 
cially over  those  of  the  Hottentot  women,  fat  is  developed  usually  in 
considerable  quantities. 

This  superficial  layer  of  fat  is  also  generally  thicker  in  children 
and  in  women  than  in  men. 

Again,  there  are  other  peculiar  situations  in  which  fat  is  almost 
invariably  encountered,  as  in  the  orbit,  in  the  articulations,  where  it 
constitutes  the  glands  of  Havers,  in  the  shafts  of  the  long  bones 
forming  the  marrow,  in  the  vertebral  canal,  and  in  many  other 
localities  where  vacancies  occur  which  require  to  be  filled  up.  The 
marrow  differs  only  from  ordinary  fat  in  that  the  cells  composing  it 
are  more  circular,  with  but  little  admixture  of  cellular  tissue. 

On  the  other  hand,  there  are  situations  in  which,  under  no  circum- 
stances, is  fat  developed,  as  in  the  eyelids,  in  the  axillae,  between 
overlapping  muscles,  and  in  the  genital    organs. 

Quantity. — The  amount  of  fat  varies  greatly  in  different  species  of 
mammalia,  in  different  individuals  of  the  same  species,  and  in  the 
same  animal  at  different  times. 


PAT.  261 

Thus,  certain  animals  seem  to  have  a  peculiar  aptitude  for  the 
formation  of  fat,  as  the  pig. 

Again,  the  various  members  of  one  family  are  sometimes  observed 
to  be  remarkable  for  the  constitutional  predisposition  exhibited  to  the 
formation  of  fat.  Again,  other  families  are  met  with  equally  remark- 
able for  their  indisposition  to  fatten. 

Lastly,  in  some  animals  the  fat  accumulates  at  particular  periods 
in  greatly  increased  quantities,  as  in  the  hibernating  mammalia,  and 
in  the.  larvae  of  insects.  In  man  the  fat  usually  undergoes  an  aug- 
mentation after  the  meridian  of  life  has  been  passed. 

Castration  peculiarly  predisposes  the  system  to  the  formation  of  fat. 

Occasionally,  also,  fat  is  secreted  in  vast  and  abnormal  quantities : 
where  this  augmentation  is  general,  it  constitutes  the  diseased  condi- 
tion of  obesity;  and  where  it  is  only  partial,  it  gives  rise  to  tumours, 
often  of  great  magnitude. 

In  general,  a  certain  degree  of  fatness  argues  a  healthy  and  vigorous 
condition  of  the  system,  while  its  excess  or  inordinate  accumulation 
denotes  either  a  degree  of  weakness  of  constitution  or  a  peculiar  and 
unexplained  state  of  the  system. 

Disappearance. — Of  all  the  solids  in  the  body,  fat  is  developed  and 
destroyed  with  the  greatest  rapidity:  in  illness,  it  disappears  with  sur- 
prising quickness,  and  is  formed  again,  under  the  influence  of  recovery, 
with  almost  equal  celerity. 

The  exact  changes  which  occur  during  the  disappearance  of  fat 
are  unknown;  whatever  they  may  be,  they  doubtless  affect  each 
individual  fat  vesicle  throughout  the  body,  and  their  nature  being 
ascertained  in  a  single  cell  would  serve  to  explain  the  disappearance 
of  fat  over  the  entire  body.  It  is  uncertain  whether  the  contents  of 
the  vesicle  disappear,  the  membrane  remaining,  or  whether  both  are 
effaced  together.  Beclard  says  that  the  fat  vesicles  themselves  disap- 
pear.* Hunter,  on  the  contrary,  assures  us  that  they  may  be  distin- 
guished even  when  they  are  empty. f  Gurlt  states  that  they  contain 
serosity  in  place  of  grease  in  lean  animals.  J 

The  immediate  cause  of  the  disappearance  of  fat  most  probably 
depends  upon  interrupted  nutrition  ;  the  contents  of  the  cells  escaping 
through  their  walls  become  absorbed  by  the  lymphatics,  and  thus 
removed  into  the  circulation.     This  view  is  supported  by  the  observa- 

*  Analomie  Generate,  p.  163. 

f  "Remarks  on  the  Cellular  Membrane,"  in  Med.  Obs.  and  Inq.,  vol.  ii.,  Lon.,  1757. 

I  Physiologie,  p.  20. 


262  THE     SOLIDS. 

tion  of  Henle,  who  states  that,  after  repeated  losses  of  blood,  the  quan- 
tity of  grease  in  the  blood  augments  considerably,  on  the  surface  of 
which  it  is  often  seen  swimming  as  a  cream  or  pellicle. 

Uses. — The  uses  of  fat  are  manifold  and  important. 

1st.  It  serves  to  impart  softness  to  the  texture  of  the  skin. 

2d.  It  adds  grace  and  symmetry  to  the  outlines  of  the  body. 

3d.  In  certain  situations,  as  in  the  soles  of  the  feet,  in  the  palms  of 
the  hands,  and  over  the  glutei  muscles,  it  serves  as  a  protection  against 
the  effects  of  pressure. 

4th.  Being  a  bad  conductor  of  caloric,  it  prevents  the  too  rapid 
dissipation  of  the  heat  generated  in  the  system. 

5th.  It  is  to  be  regarded  as  a  reserve  store  of  nourishment  set  apart 
by  the  system  during  the  period  of  its  health  and  strength,  and 
designed  to  meet  certain  exigencies,  when  the  inhei'ent  powers  of  the 
constitution  are  called  into  requisition,  as  in  times  of  hunger  and 
sickness. 

Distinctive  Characters  of  Oil  Globules. — The  contents  of  fat  ves- 
icles are,  as  already  stated,  of  an  oleaginous  nature,  which,  when  they 
escape  from  the  vesicles,  assume  the  form  of  oil  drops;  these  are  often 
met  with  in  the  various  fluids  and  solids  of  the  system  apart  from  the 
fat  vesicles,  from  which  it  is  necessary  that  they  should  be  discrimi- 
nated. There  are  several  characters  by  which  oil  globules  may  be 
distinguished  from  true  fat  vesicles;  thus,  they  are  of  a  fluid  nature, 
are  usually  perfectly  spherical,  and,  on  account  of  their  fluidity,  in 
place  of  being  globular,  are  generally  flat;  they  are  seen  sometimes 
to  alter  their  shape,  as  when  they  roll  over  on  the  surface  of  the 
object-glass,  or  come  in  contact  with  obstacles;  they  reflect  the  light 
less  powerfully,  and,  lastly,  the  slightest  degree  of  pressure  causes 
them  to  coalesce. 

There  is  but  little  probability  of  confounding  oil  globules  with  air 
bubbles ;  these  have  a  different  colour,  reflect  the  light  differently,  and 
are  perfectly  globular. 

See  Appendix,  page  538. 


FAT.  263 


PAT. 


[No  farther  hints  are  necessary  on  the  preparation  of  fat  for  examination, 
or  the  use  of  reagents  while  under  examination,  than  those  given  in  the  text. 
In  order  to  display  the  blood-vessels  of  the  fat  vesicles,  their  injection  is 
necessary.  These  vessels  are  represented  in  Plate  LXX.,  fig.  3,  and  their 
existence  is  referred  to  in  the  Appendix,  page  538. 

These  vesicles  can  only  be  injected  when  the  injecting  material  is  very 
fine,  and  the  operation  is  perfectly  successful.  In  those  instances  in  which 
the  papillae  of  the  skin  are  well  injected,  the  fat  vesicles  will  also  be  found 
more  or  less  completely  injected ;  the  injection  must  be  made  from  the 
main  vessel,  usually  the  vein,  that  supplies  the  part.] 


264  THE     SOLIDS. 


ART.    IX.  — EPITHELIUM, 

As  the  external  surface  of  the  body  is  invested  with  a  cuticle  which 
has  received  the  name  of  Epidermis,  so  are  its  internal  free  surfaces 
in  like  manner  clothed  with  a  delicate  pellicle  which  has  been  denom- 
inated Epithelium. 

Both  the  epidermis  and  epithelium  are  constituted  of  cells :  there  is 
this  difference,  however,  between  them,  that  while  the  former,  by  the 
intimate  union  and  super-imposition  of  its  cells,  exists  as  a  distinct  and 
continuous  membrane,  the  latter,  owing  to  the  feeble  cohesion  of  its 
constituent  cells,  can  scarcely,  except  in  certain  situations,  be  shown 
to  exist  as  a  united  and  extended  structure.* 

The  epidermis  and  epithelium  are,  therefore,  hardly  to  be  regarded 
as  distinct  structures,  but  rather  as  the  same,  the  differences  observed 
between  them  being  merely  modifications,  the  result  of  the  different 
circumstances  to  which  they  are  each  subject. 

The  essential  identity  of  the  two  may  be  shown  by  an  examination 
of  the  epidermis  at  the  outlets  and  inlets  of  the  body,  where,  by  gradual 
transition,  it  may  be  traced  inwards  into  the  condition  of  epithelium; 
and  this,  also,  traced  from  within  outwards,  will  be  observed  gradually 
to  acquire  the  characters  of  epidermis;  so  that,  within  a  certain  dis- 
tance of  the  termination  of  the  cavities  of  the  body,  which  open 
externally,  the  epithelium  may  also  be  demonstrated  as  a  distinct 
membrane;  this  membrane  may  be  followed  in  man  from  the  lips  as 
far  backwards  as  the  posterior  part  of  the  mouth,  also  passing  over 
the  tongue;  and  in  the  horse  and  in  birds  it  may  be  shown  to  exist  in 
the  stomach  and  gizzard. 

The  epithelium  will  be  first  described,  inasmuch  as  its  organization 
would  appear  to  be  more  simple  than  that  of  the  epidermis,  which,  by 
modifications  of  its  cells,  is  converted  into  so  many  apparently  distinct 
structures. 

It  has  been  remarked  that  the  internal  free  surfaces  of  the  body  are 
covered  by  epithelium:  these  surfaces  comprise  those  of  both  the 

*  Leeuwenhoek  first  discovered  in  the  mucus  of  the  vagina  little  scales,  which  he 
presumed  formed  the  internal  membrane  of  that  canal,  and  from  which  he  conceived 
they  become  detached  by  coitus.  (Opera,t.  i.  p.  153. 155.)  He  likewise  noticed  that 
the  mucus  of  the  mouth  contained  scales,  (Ibid.  t.  hi.  p.  51,)  and  he  saw  also  the 
cylindrical  epithelial  cells  of  the  intestinal  cavity.     (Ibid.  p.  54.  61.) 


EPITHELIUM.  2G5 

open  and  the  closed  cavities,  the  former  of  which  include  the  aliment- 
ary canal  from  mouth  to  anus,  the  genito-urinary  organs  and  passages 
of  both  the  male  and  female,  and  the  respiratory  track,  consisting  of 
the  trachea,  bronchi,  cells  of  the  lungs,  and  nares;  the  latter  consist 
of  the  great  serous  sacs  of  the  head,  chest,  and  abdomen,  and  the  lesser 
ones  of  the  pericardium,  tunica  vaginalis,  the  cavities  of  the  joints, 
and  of  the  lymphatic  and  blood  vessels,  including  the  heart. 

The  bursas  are  said  by  Henle*  not  to  be  furnished  with  an  investing 
epithelium — a  statement  to  be  received  with  some  degree  of  hesitation. 

It  would  appear,  therefore,  that,  with  the  single  doubtful  exception 
alluded  to,  every  free  surface  of  the  body  is  invested  with  its  own 
appropriate  epithelium,  the  ventricles  of  the  brain  even  being  lined 
with  an  epithelium  proper  to  them,  and  the  surface  of  the  cornea  being 
covered  with  one  also.  The  existence  of  an  epithelium  in  this  latter 
situation  may  be  directly  proved  by  means  of  the  microscope  :  and  it 
may  be  inferred  from  the  observation  of  the  fact,  that  in  the  general 
casting  of  the  epiderm  of  snakes  and  other  reptiles,  a  delicate  film  is 
likewise  thrown  off  from  the  surface  of  the  cornea. 

The  epithelium  has  not  the  same  character  in  the  different  situ- 
ations in  which  it  is  encountered,  but  the  cells  of  which  it  is  composed 
differ  in  form  and  size,  according  to  age  and  the  locality  occupied  by  it. 

The  several  varieties  of  epithelium  may  be  reduced  into  two  prin- 
cipal types,  in  the  first  of  which  the  cells  are  more  or  less  circular  or 
polygonal,  and  in  the.  second  are  elongated  and  conoid.  These  two 
forms  may  be  distinguished  by  the  appellations  of  Tessellated  or  Pave- 
ment Epithelium,  and  Cylindrical  or  Conoidal  Epithelium.  (See 
Plate  XX.  figs.  1  and  2.) 

The  Conoidal  Epithelium  admits  of  sub-division  into  Naked 
Conoidal  Epithelium  and  Ciliated  Conoidal  Epithelium. 

TESSELATED    EPITHELIUM. 

Form. — The  cells  of  this  description  of  epithelium  form  many 
layers,  are  flattened,  and  either  circular,  polygonal,  or  irregular  in 
outline:  the  younger  cells  are  mostly  of  the  first  shape,  and  are 
thicker  than  the  older  ones,  which  are  irregular  in  form,  thin  and 
membranaceous,  while  the  polygonal  cells  are  encountered  more 
particularly  in  certain  situations,  as  on  the  choroid  plexus,  pericar- 
dium, and  serous  membranes  in  general.     The  polygonal  shape  is 

*  Anal.  Gen.  vol.  vi.  p.  225. 


266  THE     SOLIDS. 

produced  by  the  mutual  compression  exerted  by  the  cells  upon  each 
other,  and  consequent  adaptation. 

Size. — The  size  of  the  cells  of  pavement  epithelium  varies  both 
according  to  age  and  locality;  the  younger  and  deeper  seated  cells 
are  of  course  smaller  than  the  older  and  more  superficial  ones;  the 
larger  cells  are  met  with  in  those  situations  where  the  epithelium  is 
continuous  with  the  epidermis,  as  in  the  mouth  and  oesophagus,  the 
vagina,  urethra,  and  bladder,  the  commencement  of  the  rectum,  the 
inferior  division  of  the  nares,  lining  the  eyelids,  and  covering  the 
cornea.  (See  Plate  XX.  Jig.  1.)  On  the  contrary,  the  epithelium 
of  the  pericardium,  ventricles,  aorta,  and  of  most  of  the  closed  cavi- 
ties, is  composed  of  cells  which  are  very  much  smaller  in  size  than 
those  of  the  localities  previously  enumerated.     (See  Plate  XXII.) 

Structure. — Epithelial  cells  illustrate  faithfully  the  doctrine  of  cell 
development,  each  consisting  of  a  nucleus,  cell  wall,  and  intervening 
space  enclosing  fluid,  both  the  nucleus  and  the  cell  wall  exhibiting  a 
granular  composition. 

It  has  been  observed,  that  the  younger  cells  are  thicker  than  the 
older  and  fully  developed  ones,  which  become  reduced  to  mere  mem- 
branous expansions,  from  which  it  follows  that  the  space  intervening 
between  the  nucleus  and  cell  wall  is  greatest  in  the  younger  cells, 
while  it  is  almost  obliterated  in  the  older.  The  smaller  cells  are  also 
more  granular  than  the  larger :  now,  these  two  facts  stand  in  close  rela- 
tionship with  the  function  discharged  by  these  cells,  and  which  is  so 
much  the  more  active  as  the  cavity  is  large  and  the  granules  numerous. 

The  nucleus  is  likewise  best  seen  in  the  younger  cells:  in  the  older 
ones  it  becomes  either  entirely  obliterated,  or  it  escapes  from  the 
cavity  of  the  cell,  the  position  which  it  previously  occupied  in  it 
being  indicated  by  a  depression;  it  is  for  the  most  part  circular;  but 
occasionally,  and  particularly  in  certain  localities,  it  is  found  to  be 
oval,  as  in  the  epithelium  of  the  lower  two-thirds  of  the  uterus,  in 
that  of  the  pericardium,  and  also  in  that  of  the  blood-vessels,  the 
aorta  excepted ;  it  sometimes  occupies  a  central  position  in  each  cell ; 
at  others  it  is  eccentric. 

The  properties  of  pavement  epithelial  cells,  as  well  as  their  form, 
size  and  granular  texture,  alter  also  with  age :  thus  the  younger  cells 
are  dissolved,  with  the  exception  of  the  nucleus,  by  acetic  acid,  while 
the  same  reagent  applied  to  the  older  ones  produces  scarcely  any 
appreciable  effect. 

Epithelial  cells,  on  the  addition  of  water,  or  after  death,  become 


EPITHELIUM.  267 

white  and  opaque — a  common  effect  of  water  on  all  animal  struct- 
ures. The  change  in  the  case  of  the  epithelial  cells  probably  depends 
upon  the  coagulation  of  their  fluid  contents;  and  to  it  the  character- 
istic dulness  of  the  eye  after  death  is  due. 

Distribution. — This  form  of  epithelium  is  more  extensively  dis- 
tributed than  the  conoidal  variety:  it  is  encountered  on  the  free  and 
serous  surfaces  of  all  the  closed  cavities,  as  of  the  cranium,  thorax 
and  pericardium,  abdomen  and  tunica  vaginalis,  lining  the  lymphatic 
and  blood  vessels;  even  the  ventricles  of  the  brain  itself,  in  which  it 
rests  immediately  upon  the  cerebral  substance,  are  not  free  from  it: 
it  is  met  with  likewise  near  the  terminations  of  those  cavities  which 
open  externally,  as  in  the  mouth,  where  it  extends  as  far  backwards 
as  the  cardiac  extremity  of  the  stomach,  in  the  lower  portions  of  the 
nares,  whence  it  passes  into  the  frontal  sinuses,  in  the  vagina  and  uterus, 
the  lower  two-thirds  of  which  it  lines,  as  also  the  urethra.  In  the  male 
subject  it  passes  over  the  glans  penis,  and  then  enters  the  urethra. 

The  epithelium  of  the  urinary  apparatus  should  perhaps  be  referred 
to  the  pavement  epithelium :  its  cells,  however,  vary  very  consider- 
ably in  form:  thus,  many  of  them  decidedly  resemble  the  variety  of 
epithelium  under  discussion  ;  others,  however,  are  clavate,  the  narrow 
or  fixed  extremity  being  often  produced  into  a  long  thread  or  filament; 
and  again,  others  imperfectly  represent  the  conoidal  variety  of  epithe- 
lium; these  last,  as  well  as  the  clavate  cells,  are  met  with  in  the 
greatest  quantity  in  the  upper  part  of  the  bladder,  and  in  the  ureters. 

CONOIDAL    EPITHELIUM. 

Form  and  Size. — The  cells  of  this  form  of  epithelium  are  much 
more  regular  in  size  and  shape  than  those  of  the  tesselated  or  pave- 
ment kind :  the  term  cylindrical  usually  applied  to  them  is,  however, 
far  from  accurate,  since  they  do  not  possess,  even  in  a  slight  degree, 
the  outward  form  of  a  cylinder :  the  word  conoidal,  here  used,  serves 
to  express  much  more  closely  the  real  form  of  the  cells  of  this  variety 
of  epithelium,  although  it  fails  to  give  an  exact  idea  of  their  shape: 
thus,  the  cells  in  question  are  not  merely  conical  with  flat  summits, 
but  each  cone  is  flattened  at  the  sides,  so  that  when  the  bases  of  the 
cones  are  seen  directly,  they  exhibit  the  appearances  of  ordinary 
polygonal  tesselated  epithelium;  the  side  view  of  the  cells  will  at 
once  make  manifest  their  distinctness.     (See  Plate  XX.  Jig.  2.) 

Conoidal  epithelial  cells  are  usually  disposed  more  or  less  vertically 
to  the  surface  upon  which  they  rest,  their  narrow  extremities  being 


268  THE     SOLIDS. 

turned  downwards,  and  attached  to  that  surface,  and  the  broader  and 
free  ends  being  directed  upwards. 

Structure. — The  cells  of  conoidal  epithelium  have  precisely  the 
same  structure  as  those  of  the  previously  described  kind;  that  is, 
they  consist  of  nucleus,  cell  wall,  granules,  and  fluid  contents:  the 
chief  difference  is  one  of  form  and  not  of  structure. 

The  nucleus  is  almost  invariably  oval,  the  long  axis  corresponding 
with  that  of  the  cell  itself:  it  is  often  so  large  as  to  occasion  the  cell 
to  assume  a  ventricose  form,  it  being  contracted  immediately  above 
and  below  the  part  in  which  the  nucleus  is  situated.  Some  observers 
speak  of  two  nuclei  in  a  single  cell:  this,  however,  must  be  an 
exceedingly  rare  occurrence,  as  I  have  never  yet  met  with  a  single 
example  of  the  kind. 

The  conoidal  epithelium  is,  as  already  remarked,  divisible  into 
two  kinds. 

Naked  Conoidal  Epithelium. 

Distribution. — This  sub-division  of  epithelium,  to  which  the  des- 
cription just  given  more  immediately  applies,  is  met  with  investing 
the  mucous  membrane  of  the  alimentary  canal,  extending  from  the 
cardiac  extremity  of  the  stomach  to  within  two  or  three  inches  of  the 
rectum;  it  is  encountered  likewise  lining  the  several  ducts  and  prolon- 
gations which  communicate  with  this:  thus,  this  form  of  epithelium 
exists  in  the  gall-bladder,  where  it  is  of  a  deep  yellow  colour,  in  the 
ductus  communis  choledocus,  in  the  pancreatic  duct,  and  in  the 
mucous  crypts  or  follicles  imbedded  in  the  mucous  membrane;  It  is 
found  also  in  the  upper  portion  of  the  nares,  in  the  salivary  ducts,  in 
the  appendix  vermiformis,  and  in  modified  form  in  the  vas  deferens. 

In  the  stomach,  the  naked  conoidal  epithelium  does  not  exist  in  an 
unmixed  form ;  it  occurs  intermixed  with  pavement  epithelial  cells, 
probably  derived  from  the  oesophagus,  and  carried  down  during 
deglutition. 

It  is  in  the  gall-bladder,  the  small  intestines  and  the  appendix 
vermiformis,  that  the  naked  conoidal  epithelium  exists  in  the  greatest 
perfection, 

Ciliated  Conoidal  Epithelium. 

The  cells  of  this  variety  of  conoidal  epithelium  agree  precisely  in 
form,  size,  and  arrangement  with  those  of  the  first  described  sub- 


EPITHELIUM.  209 

division,  the  only  difference  being,  that  they  are  possessed  of  the 
singular  addition  of  vibratile  cilia.*     (See  Plate  XXI.  jig.  3.) 

The  cilia  taper  from  base  to  apex,  and  are  attached  to  the  thick- 
ened margins  of  the  summits  of  the  cells,  ten  or  twelve  of  them 
belonging  to  each.  In  the  frog  they  would  appear  to  be  not  merely 
attached  to  a  circular  line,  but  also  to  the  segment  of  the  cell 
described  within  this.     (See  Plate  XXI.  jig.  1.) 

During  life,  the  cilia  are  in  a  constant  state  of  activity:  the  power 
by  which  their  motions  are  effected  is,  however,  involved  in  the 
greatest  obscurity:  it  can  scarcely  be  the  result  of  muscular  structure, 
as  some  have  supposed,  since  the  entire  cilium  is  many  times  smaller 
than  the  smallest  muscular  fibre.  The  idea  has  been  put  forth  that 
the  cilia  are  hollow;  that  they  communicate  with  a  vessel  which 
runs  along  their  bases,  containing  fluid ;  and  that  they  are  moved  by 
the  successive  injection  and  expulsion  of  this  fluid. 

One  fact  has  been  observed,  which  affords  countenance  to  the 
above  explanation  of  the  motion  of  the  cilia,  viz :  that  this  takes 
place  in  a  determined  direction :  commencing  in  the  cilia  on  one 
side,  it  runs  along  them  to  the  opposite,  the  several  cilia  being  thus 
successively  called  into  action.  It  is  this  peculiar  character  of  the 
motion  of  the  cilia  which  has  led  to  its  comparison  with  the  waving 
of  a  corn-field  over  which  the  wind  passes  in  successive  gusts.  The 
motion,  in  whatever  way  effected,  is  singularly  beautiful,  and,  strange 
to  say,  exhibits  many  of  the  characters  of  volition :  thus,  it  will  some- 
times cease  altogether  for  a  time,  and  then  suddenly  commence  again. 
It  is  also  sufficiently  powerful  to  effect  the  entire  displacement  of  the 
cell  or  corpuscle  to  which  the  cilia  are  attached,  and  many  of  which 
may  frequently  be  seen  moving  freely  and  quickly  about,  usually  in 
circles,  in  the  field  of  the  microscope.  This  curious  spectacle  is 
most  readily  witnessed  in  the  ciliary  cells  of  the  trachea  of  the  frog, 
which  are  of  a  different  form  from  those  of  the  mammalia,  being 
rounded  in  place  of  elongated  and  conoidal.     (See  Plate  XXI.  jig.  1.) 

The  combined  motion  of  the  cilia  is  also  capable  of  putting  in 
movement  either  fluids  or  solid  particles  which  may  come  into  contact 
with  them.     This  fact  those  who  are  given  to  microscopic  investi- 

*  To  Purkinje  and  Valentin  especially  belong  the  honour  of  making  known  in  all 
its  extent  the  phenomenon  of  ciliary  motion,  and  which  before  that  time  had  been 
observed  only  in  some  few  of  the  lower  animals,  and  concerning  the  nature  of  which 
many  errors  prevailed.  They  discovered  it  in  the  respiratory  and  female  genital 
organs  in  1834.     (Mailer,  Archiv.  1834,  p.  391.) 


270  THE     SOLIDS. 

gation  will  have  had  many  opportunities  of  verifying,  and  one  may 
easily  at  any  time  acquire  the  proof  of  it  by  mixing  with  the  fluid  in 
which  the  cilia  are  acting  some  fine  powder,  as,  for  example,  of  carbon. 

The  motion  of  the  cilia,  when  acting  in  combination,  is  stated  to 
take  place  always  in  a  determined  direction  from  within  outwards. 
It  would  appear,  however,  from  the  observations  of  Purkinje  and 
Valentin*  that  the  direction  is  capable  of  reversion :  thus,  these 
observers  saw  the  accessory  branchiae  of  the  anodon  vibrate  during 
from  six  to  seven  minutes  in  one  direction,  and  afterwards,  during 
the  same  lapse  of  time,  in  an  opposite. 

The  influence  of  physical  and  chemical  reagents  upon  the  vibratile 
movement  has  been  carefully  examined.  Thus,  if  a  portion  of 
vibratile  epithelium  be  touched  or  scraped,  the  motions  of  the  cilia  will 
become  more  active,  and  sometimes  commence  again  even  after  they 
had  become  extinct.  They  cease  at  a  temperature  below  the  freezing 
point,  and  at  a  degree  of  heat  sufficient  to  occasion  the  coagulation 
of  the  animal  fluids.  Galvanism  destroys  their  action,  but  in  a  local 
manner — a  fact  which  a  reference  to  the  constitution  of  epithelium 
by  the  union  of  separate  cells  may  serve  to  explain.  Among  chemical 
reagents,  narcotics  are  without  influence;  acetic  and  the  mineral 
acids  destroy  the  motion,  as  also  caustic  ammonia,  nitrates  of  potash 
and  of  silver.  The  serum  of  the  blood  prolongs  its  duration.  Urine 
and  white  of  egg  are  without  effect  upon  it.  Bile  instantly  destroys 
the  activity  of  the  cilia. 

The  ciliary  motion  soon  ceases  after  death  in  the  mammalia,  but 
continues  in  many  of  the  invertebrata,  and  especially  in  several  of 
the  mollusca,  as,  for  example,  in  the  river  muscle  and  the  oyster,  for 
days  after  the  death  of  the  animal. 

It  would  appear,  therefore,  that  each  ciliated  corpuscle  bears  the 
closest  possible  resemblance  to  many  of  the  infusory  animalcules, 
and  it  is  questionable  whether  its  claim  to  be  regarded  as  a  distinct 
entity  be  not  equally  strong. 

Distribution. — Ciliated  epithelium  has  not  been  as  yet  discovered 
among  the  mammalia  in  any  closed  cavity,  but  always  in  situations 
which  communicate  with  the  air;  thus,  it  is  met  with,  as  is  generally 
known,  lining  the  trachea  and  bronchi,  extending  even  to  their 
minutest  ramifications ;  again,  it  is  encountered  in  the  Fallopian 
tubes,  and  lining  the  upper  third  of  the  cavity  of  the  uterus  of  adult 
animals,  but  not  that  of  young  mammalia.     There  is  yet  another 

*  Motus  Vibrat.,  p.  67. 


EPITHELIUM.  271 

locality  in  which  I  believe  it  also  to  exist,  viz:  in  the  convolutions  of 
the  tubuli  serniniferi  of  the  epididymis. 

On  the  other  hand,  there  are  many  situations  in  which  it  has  been 
repeatedly  asserted  to  exist,  but  in  which  patient  and  repeated  inves- 
tigation has  failed  to  reveal  its  presence;  as,  for  example,  in  the 
ventricles  of  the  brain,*  covering  the  pia  mater,  and  lining  the  eyelids 
and  frontal  sinuses.f 

The  epithelium  of  these  several  parts,  on  the  contrary,  is  pavement 
and  not  ciliated  epithelium.     (See  Plate  XXIV.) 

Purkinje,J  in  describing  the  epithelium  of  the  ventricles,  does  so 
most  circumstantially,  and  states  that  he  followed  the  vibratile  move- 
ment in  the  sheep  from  the  lateral  ventricles  through  the  third 
ventricle,  and  by  the  aqueduct  of  Sylvius  into  the  fourth. 

Valentin  §  confirms  the  accuracy  of  this  description  as  regards  man. 

We  find  Henle||  describing  the  epithelium  of  the  ventricles  as  a 
cuneiform  ciliated  epithelium;  and  in  Gerber's  General  Anatomy, 
we  remark  that  it  is  stated  to  be  a  tesselated  ciliated  epithelium.  It  is 
singular  how  so  great  an  error  could  have  originated,  and  still  more 
so  how  it  could  have  been  so  long  perpetuated. 

DEVELOPMENT    AND    MULTIPLICATION    OF    EPITHELIUM. 

I 

Each  epithelial  cell  is  first  detected  as  a  nucleus  without  any 
appearance  of  cell  wall  around  it:  this,  however,  may  exist,  closely 
embracing  the  nucleus,  even  from  the  earliest  period  at  which  this 
can  be  observed.  After  a  time,  however,  a  transparent  border 
becomes  visible,  surrounding  the  nucleus:  the  width  of  this  goes  on 
gradually  increasing,  until  at  length  the  full  dimensions  of  the  cell 
have  been  attained:  now,  the  outer  limit  of  this  border  doubtless 
indicates  the  cell  wall,  the  clear  space  between  it  and  the  nucleus 
being  in  the  younger  epithelial  cells  filled  with  fluid.  In  the  conical 
epithelium  the  cell  wall  is  not  developed  equally  around  the  nucleus 
as  in  the  pavement  epithelium,  but  chiefly  in  two  opposite  directions. 

It  has  been  observed,  that  young  epithelial  cells  are  thicker  and 
rounder  than  the  older  ones ;  it  has  also  been  remarked,  that  they  are 
more  granular;  facts  which  stand  in  close  relation  with  their  func- 
tional activity. 

It  has  been  noticed  likewise,  that  the  nucleus  in  the  progress  of 

*  Purkinje  in  Miiller,  Archiv.  1836,  p.  289. 

f  Henle,  Anat.  Gen.  t.  vi.  p.  252.  \  Miiller,  Archiv.  1836. 

\  Repertorium,  1831,  p.  158.  278.  ||  Anat.  Gen.  tvi.  p.  253. 


272  THE     S  O  L  I  D  3  . 

development  becomes  either  obliterated,  or  that  it  escapes  from  the 
cell.  Now,  it  has  struck  me  that  this  disappearance  of  the  granular 
nucleus  and  granules  of  the  cell  wall  might  possibly  be  connected 
with  the  reproduction  or  multiplication  of  epithelial  cells,  as  well  as 
of  cells  occurring  elsewhere  than  in  the  epithelium,  and  that  each 
granule  might  in  reality  be  an  epithelial  cell  in  embryo.  This  is  of 
course  but  a  conjecture:  it  is  one,  however,  which  would  appear  not 
to  be  contradicted  by  any  other  known  fact,  and  to  have  analogy  in 
its  favour;  the  mode  of  reproduction  among  the  lower  algee  being 
precisely  similar. 

The  occurrence  of  two  nuclei  in  the  same  cell  has  been  recorded 
by  some  observers,  and  who  have  from  this  fact  drawn  the  inference, 
that  epithelial  cells  are  multiplied  by  division.  This  method  of 
increase  cannot,  however,  be  presumed  to  prevail  to  any  extent,  since 
it  is  a  circumstance  of  extreme  rarity  to  meet  with  two  nuclei  in  the 
same  cell. 

NUTRITION    OF    EPITHELIUM. 

The  epithelium  has  no  immediate  or  structural  connexion  with  the 
parts  which  lie  immediately  beneath  it,  neither  does  it  receive  blood- 
vessels and  nerves  from  those  parts ;  it  is  simply  dependent  upon  them 
for  the  supply  of  nourishment,  of  which  it  is  the  recipient,  and  which 
is  derived  from  the  blood-vessels  distributed  throughout  the  tissue  of 
the  true  skin  lying  beneath  it,  and  from  which  vessels  the  plasma  is 
continually  escaping  by  transudation  or  exosmosis. 

DESTRUCTION    AND    RENEWAL    OF    EPITHELIUM. 

The  epithelium  in  every  part  of  the  body  is  continually  undergoing 
a  process  of  destruction,  and  consequent  renewal. 

It  is  less  easy  to  establish  the  fact  of  the  destruction  of  the  epi- 
thelium in  the  closed  cavities  than  in  the  open;  nevertheless,  that  it 
really  does  take  place  even  in  these,  may  be  inferred  from  the  observa- 
tion of  the  fact  that  the  cells  of  epithelium  encountered  in  such  local- 
ities represent  every  degree  of  development,  many  of  the  older  ones 
also  being  destitute  of  nuclei,  and  more  or  less  broken  into  fragments. 
It  is  probable,  however,  that  the  process  of  destruction  is  slower  in 
the  closed  than  in  the  open  cavities. 

In  the  open  cavities,  the  destruction  of  epithelium  is  doubtless  more 
considerable  and  more  rapid;  it  is  also  more  easy  to  determine  in 
these;  thus,  during  mastication,  deglutition,  and  digestion,  a  consider- 


EPITHELIUM.  273 

able  amount  of  epithelium  becomes  disturbed,  removed  from  the  sur- 
face to  which  it  was  attached,  and  mixed  up  with  the  saliva,  mucus, 
gastric  fluid,  food,  &c,  and  finally  is  discharged  from  the  system  with 
the  faeces,  in  which,  by  microscopic  examination,  it  may  readily  be 
detected. 

The  fact  of  the  gradual  and  continual  destruction  of  epithelium 
may  likewise  be  ascertained  by  an  examination  of  the  several  fluids 
discharged  from  the  system,  as  the  saliva,  the  mucus,  from  either 
mouth,  nose,  lungs,  urine,  seminal  or  menstrual  fluids,  in  all  of  which 
the  microscope  will  reveal  an  abundance  of  epithelial  cells. 

The  same  fact  may  also  be  determined  by  a  microscopic  examina- 
tion of  the  scum  which  collects  during  the  night  on  the  lips  and 
around  the  base  of  the  teeth  of  many  persons. 

In  certain  situations  the  epithelium  undergoes  not  merely  a  gradual, 
but  also  a  periodical  destruction,  as  in  the  uterus  at  the  monthly 
periods  and  after  parturition. 

The  continual  destruction  of  epithelium  having  been  thus  rendered 
manifest,  its  renewal  follows  as  a  matter  of  necessity. 

In  irritation  of  the  mucous  membrane  of  the  bronchi,  nose,  and 
alimentary  canal,  it  is  possible  that  the  epithelium,  during  the  period 
of  the  continuance  of  the  irritation,  is  entirely  destroyed. 

.  USES    OF    EPITHELIUM. 

*  The  first  use  of  the  epithelium  is  a  passive  one,  it  serving  like  the 
epidermis  as  a  protection  to  the  more  delicate  parts  which  lie  imme- 
diately beneath  it. 

The  second  use  is  active,  the  epithelium  doubtless  being  an  import- 
ant agent  in  secretion. 

Each  epithelial  cell  may  be  regarded  as  a  gland  reduced  to  its  most 
simple  type  or  condition,  it  embodying  all  that  is  essential  in  the 
largest  and  most  complex  secreting  organ,  viz:  the  true  secreting 
structure. 

The  nature  of  the  fluid  secreted  by  epithelial  cells  is  not  every 
where  identical,  but  varies  according  to  their  exact  structure  and  the 
locality  in  which  they  are  found :  thus,  in  some  situations,  they  secrete 
serum,  as  in  the  serous  sacs :  in  others  mucus,  as  in  the  mouth,  nose, 
alimentary  canal,  &c;  in  others  synovia,  as  in  the  joints;  in  the 
stomach  and  in  the  duodenum,  they  assist  in  the  elaboration  of  the 
fluids  which  are  there  found. 

That  the  epithelial  cells  are  the  real  agents  engaged  in  the  pro- 

18 


274  THE     SOLIDS. 

duction  of  the  several  fluids  named,  is  rendered  certain  by  the  facts 
that  they  correspond  precisely  with  the  undoubted  secreting  structure 
of  true  glands;  and  further,  that  in  the  situations  where  they  are 
found,  no  other  organization  exists  to  which  the  function  of  secretion 
could  with  any  degree  of  probability  be  assigned. 
•  The  importance  of  the  office  discharged  by  the  epithelium  explains, 
then,  the  universality  of  its  distribution. 

The  diffusion  of  epithelial  or  secreting  cells  over  the  surface  of 
membranes  which  require  to  be  kept  continually  moistened  by  a  suit- 
able fluid,  affords  a  beautiful  example  of  the  wise  adaptation  of  means 
to  an  end:  by  no  other  means  than  that  employed  could  the  end  in 
view  be  so  surely  accomplished,  or  with  so  great  an  economy  of  space. 

The  above-described  uses  of  epithelium  are  common  to  it  wherever 
encountered:  the  third  use  is  mechanical,  and  accomplished  only  by 
the  ciliated  form  of  epithelium. 

It  has  already  been  observed  that  the  force  of  the  combined  action 
of  the  cilia  is  so  great  as  to  enable  them  to  carry  along  with  or  drive 
before  them  fluids,  and  even  solid  particles  which  may  happen  to  come 
in  contact  with  them :  it  has  likewise  been  remarked  that  the  direction 
of  their  united  action  is  invariably  from  within,  outwards  or  towards 
the  outlets  of  the  body;  at  least  it  is  so  among  the  mammalia.  From 
a  knowledge  of  these  facts  it  is  not  difficult  to  suggest  the  probable 
use  of  vibratile  epithelium  in  the  localities  in  which  it  has  hitherto 
been  discovered  in  man  and  the  mammalia. 

Thus  in  the  bronchi  and  trachea,  it  may  be  presumed  to  be 
designed  to  facilitate  the  escape  from  those  passages  of  any  foreign 
particles  which  may  have  found  entrance  to  them. 

Again,  in  the  Fallopian  tubes  and  upper  portion  of  the  uterus,  it  can 
scarcely  be  questioned,  but  that  its  use  is  to  hasten  the  progress  of 
the  ovum  from  the  ovary  to  the  uterus;  and,  presuming  that  the 
direction  of  the  action  of  the  cilia  may  be,  and  is  sometimes  reversed, 
the  vibratile  epithelium  of  these  parts  may  be  further  intended  to 
ensure  the  more  speedy  transmission  of  the  seminal  fluid  along  the 
Fallopian  tubes  to  the  ovary,  upon  which  it  has  been  detected  by  more 
than  one  observer. 


EPITHELIUM.  275 


EPITHELIUM. 


[Microscopic  examination  has  revealed .  the  fact  that  many  tumours 
supposed  to  be  cancerous,  especially  certain  tumours  about  the  lips,  were 
composed  of  degenerated  epithelium.  Ecker*  has  described  these  tumours 
of  the  lip,  and  denominated  them  bastard  cancer  of  the  lip.  It  is  now 
ascertained  that  these  tumours  are  not  confined  to  the  skin,  but  occur  in  the 
mucous  membranes.  Rokitansky  has  found  them  on  the  lining  membrane 
of  the  larynx,  trachea,  stomach,  intestines,  and  bladder.  They  may  be  also 
met  with  on  the  dorsal  aspect  of  the  hand,  on  the  cheeks,  scrotum,  prepuce, 
and  it  may  be  the  chimney-sweep's  cancer  is  but  an  epithelial  tumour. 
Lebert  regards  them  as  benign,  since  they  contain  no  cancer-cell.  Roki- 
tansky and  Bruck  consider  them  malignant.  Dr.  Gorup  Bezanes  regards 
the  important  question  to  be,  not  whether  these  tumours  may  be  benign,  but 
whether  they  are  altogether  exempt  from  malignity:  his  observations  con- 
firm the  opinion  of  their  malignity. 

See  Archiv.  Gen.  de  Med.  torn  xxm.  p.  76,  Mai,  1850. 

See  also  Dublin  Quart.  Jour.  August,  1850,  p.  255. 

PREPARATION. 

The  text  has  already  indicated  the  different  localities  from  which  the 
various  forms  of  epithelium  may  be  obtained. 

The  pavement  or  scaly  epithelium  may  be  best  studied  by  scraping  any 
of  the  serous  membranes  gently  with  a  knife,  and  examining  the  particles 
removed.  Many  of  the  cells  after  removal  will  be  found  to  adhere  together. 
The  addition  of  a  little  weak  ascetic  acid  will  render  the  angles  of  the 
scales  more  apparent. 

The  conoldal  variety  of  epithelium  is  easily  obtained  by  macerating  any 
of  the  mucous  membranes,  as,  for  instance,  a  portion  of  the  alimentary  canal. 
By  this  process,  the  epithelium  becomes  detached,  and  may  be  collected  and 
viewed  with  the  microscope.  The  ciliated  variety  possesses  most  interest. 
The  cilia  may  be  seen  in  motion  by  taking  a  small  piece  of  the  mantle  of 
an  oyster  or  mussel,  folding  it  upon  itself,  and  placing  it  under  the  micro- 
scope so  as  to  allow  the  cilia  to  project.  The  edge  of  the  beard  will  also 
show  the  cilia  in  motion.  The  fragment  should  be  moistened  with  water, 
and  covered  with  thin  glass;  a  power  of  about  250  diameters  is  necessary 
for  good  observation.  The  currents  caused  in  the  water  by  the  cilia  in 
motion  may  be  readily  detected  by  the  suspension  of  fine  particles  of  car- 
mine or  charcoal  in  the  water.  These  particles  are  first  seen  attracted  by 
the  ciliary  motion,  and  then  repelled. 

*  Archiv.  fur  Physiol  Heilkunde,  1849. 


276  THE     SOLIDS. 

In  quadrupeds  the  ciliary  motion  may  be  observed  by  taking  a  small 
portion  of  ciliated  mucous  membrane  from  an  animal  recently  killed,  and 
folding  it  in  the  manner  already  indicated^ 

In  man  the  cilia  may  be  seen  in  motion  in  recently  detached  nasal  polypi. 
They  may  also  sometimes  be  discovered  in  mucous  discharges. 

The  ciliary  motion  may  be  studied  on  a  larger  scale  in  many  of  the  fresh- 
water infusoria,  so  abundant  during  the  summer  and  fall  months  in  small 
ponds  and  stagnant  pools. 

Epithelial  cells  may  be  preserved  in  the  flat  or  thin  glass  cell,  suspended 
in  a  weak  solution  of  chromic  acid,  or  Goadby's  B-solution.] 


EPIDERMIS.  277 


ART.   X.  — EPIDERMIS. 

The  entire  of  the  external  surface  of  the  body  is  invested  with  a 
membrane  which  has  been  denominated  epidermis,  formed  of  super- 
imposed layers  of  nucleated  cells  (see  Plate  XXIV.  fig.  3),  and  the 
number  of  which  layers  is  greatest  in  those  situations  in  which  the 
membrane  is  subject  to  the  most  pressure,  as  in  the  palms  of  the 
hands  and  soles  of  the  feet,  in  which  the  epidermis  sometimes  attains 
the  thickness  of  the  TV,  or  even  the  \  of  an  inch.* 

The  form,  structure,  and  development  of  the  cells  composing  the 
epidermis  are  in  every  respect  identical  with  those  of  the  tesselated 
variety  of  epithelium  already  described;  thus,  first,  the  younger  and 
deeper-seated  cells  are  spherical  in  outline,  and  almost  globular,  while 
the  older  and  more  superficial  cells  become  irregular  in  form,  expanded, 
thin,  and  membranaceous ;  secondly,  like  those  of  the  tesselated  epi- 
thelium, the  cells  consist  of  a  nucleus,  cell-wall,  cavity,  and  granules; 
it  is,  however,  worthy  of  remark,  that  the  nucleus,  as  well  as  the 
majority  of  the  granules  contained  in  the  epidermic  cells,  disappear 
at  an  earlier  period  of  development  than  do  those  of  the  epithelium — 
facts  which  will  be  explained  when  the  uses  of  the  epidermis  come  to 
be  treated  of;  thirdly,  the  plan  of  development  is  the  same  in  the  two 
cases,  the  cell-wall  being  developed  around  the  nucleus,  which  is  the 
part  first  formed. 

Thus  far,  then,  there  is  a  close  correspondence  between  the  epider- 
mis and  epithelium ;  so  close,  indeed,  as  to  make  it  apparent  that  the 
two  are  but  modifications  of  one  and  the  same  structure.  The  chief 
respects  in  which  it  diners  from  the  epithelium  are  in  the  compact 
and  firm  union  of  the  cells  with  each  other,  whereby  it  forms  a  distinct 
and  continuous  membrane,  and  in  the  paucity  of  granules  dispersed 
throughout  the  cells. 

The  epidermis  also  stands  in  precisely  the  same  relation  with  the 
parts  beneath  it  as  the  epithelium;  thus,  it  has  no  structural  con- 
nexion with  those  parts,  and  receives  neither  blood-vessels  nor  nerves 
from  them,  but  is  simply  dependent  upon  them  for  the  plasma  which 
is  continually  escaping  from  the  blood-vessels  of  the  true  skin.     This 

*  Leeuwenhoek  first  observed  that  the  epidermis  was  composed  of  scales  placed 
one  against  the  other,  and  also  that,  after  a  certain  lapse  of  time,  they  were  cast  off, 
and  their  place  supplied  by  others. 


278  THE     SOLIDS. 

want  of  structural  connexion  is  shown  by  the  fact  that  a  portion  of 
the  cuticle  may  be  detached  without  its  removal  occasioning  either 
pain  or  hsemorrhage. 

This  separation  of  the  epidermis  from  the  dermis  frequently  takes 
place  during  life,  as  from  a  burn,  scald,  or  blister,  or  from  the  effusion 
of  serum,  the  result,  not  of  injury,  but  of  disease.  After  death,  and 
on  the  commencement  of  decomposition,  the  epidermis  may  be 
detached  in  large  masses,  the  prolongations  sent  down  to  the  sebace- 
ous and  sudoriferous  glands  also  coming  away  with  it. 

The  epidermis  does  not  merely  cover  the  whole  external  surface 
of  the  body,  but  sends  processes  into  its  various  outlets,  as  the  mouth, 
nose,  rectum,  vagina,  and  male  urethra  ;  these  prolongations  soon  lose, 
however,  the  characters  of  epidermis,  and  acquire  those  of  epithelium. 

The  epidermis  likewise  sends  down  processes  into  the  sebaceous 
and  sweat  glands,  and  which,  forming  a  perfect  tube,  serve  to  convey 
the  secretions  of  those  glands  to  the  surface,  on  which  they  open  as 
raised  and  rounded  papillae,  with  central  depressions  and  apertures. 
(See  Plate  XXIII.  figs.  1  and  2.) 

A  sheath  of  epidermis  likewise  encircles  the  base  of  each  hair. 

The  number  of  these  infundibuliform  processes  and  salient  papillae 
which  open  on  the  surface  is  immense,  and  may  be  stated  at  about 
3,000  to  the  square  inch,  which,  computing  the  number  of  square 
inches  of  surface  in  a  man  of  average  size  at  2,500,  would  give 
7,500,000  for  the  entire  surface  of  the  body. 

In  addition  to  the  papillae,  we  observe  on  the  surface  of  the  epider- 
mis a  great  number  of  lines  or  furrows  which  map  it  out  into  a  net- 
work of  small  polygonal  and  lozenge-shaped  spaces ;  these  are  of  two 
kinds,  the  one  large  and  coarse,  and  corresponding  with  the  flexures 
of  the  joints;  the  others  smaller,  occupying  the  interspaces  between 
the  larger,  and  also  being  generally  distributed  over  the  surface  of  the 
epidermis,  where  the  articular  furrows  have  no  existence.  The  plan 
of  arrangement  of  the  smaller  lines  is  as  follows:  A  number  of  straight 
lines,  usually  from  six  to  ten,  radiate,  like  the  rays  of  a  wheel  from  its 
centre,  from  each  hair-pore;  these  usually  come  in  contact  with  the 
lines  proceeding  from  other  hairs.  These  radiating  lines  thus  mark 
out  the  surface  into  triangular  spaces,  between  which  are  usually 
situated  two  or  three  other  pores,  those  of  the  sebaceous  and  sweat 
glands;  from  each  of  these  also  similar  radiating  lines  proceed;  these 
unite  with  the  coarser  lines  given  off  from  the  hair  follicle,  and  occa- 
sion a  still  further  sub-division  of  the  surface  of  the  epidermis  into 
triangular  spaces.    The  result  of  this  minute  sub-division  is  to  occasion 


EPIDERMIS.  279 

the  whole  surface  of  the  epidermis  to  assume  a  minutely  and  beauti- 
fully reticular  appearance.  The  coarser  lines  are  best  seen  in  the 
palms  of  the  hands  and  soles  of  the  feet,  while  the  smaller  and  finer 
lines  may  be  readily  traced,  following  the  disposition  just  described  on 
the  back  of  the  hand. 

The  effect  of  water  in  rendering  the  cells  of  tesselated  epithelium 
white  and  opaque  has  been  referred  to:  its  long-continued  application 
to  even  the  living  epidermis  produces  a  similar  result,  which  most 
persons  must  have  observed,  although  some  would  be  at  a  loss  to 
account  for  it;  thus,  the  skin  of  the  fingers  of  those  who  have  been 
engaged  in  washing  for  some  hours  becomes  of  a  pearly  whiteness. 

It  sometimes  happens  that  epidermic  cells  are  developed  in  increased 
and  abnormal  quantities,  giving  rise  to  tumours,  and  which  are  by  no 
means  of  uncommon  occurrence. 

EPIDERMIS    OF    THE  WHITE    AND    COLOURED    RACES. 

Between  the  epidermis  of  the  white  and  the  coloured  races  there  is 
a  perfect  identity  of  structure ;  the  only  difference  is,  that  the  young 
epidermic  cells  of  whites  contain  little  or  no  colouring  matter,  or 
pigment  granules,  except  in  certain  situations,  while  those  of  blacks 
are  filled  with  them;  this  difference  can  scarcely  be  regarded  as  per- 
manent or  structural ;  it  is  one  rather  of  degree  than  kind,  and  over 
which,  moreover,  climate  exerts  an  all-powerful  influence. 

We  have  continual  opportunities  of  witnessing  the  effect  of  climate 
in  increasing  .the  amount  of  pigmentary  matter  in  the  skin.  All  have 
noticed  that  after  a  few  years'  residence  in  a  hot  country,  the  skin  of 
many  individuals  becomes  several  shades  darker  than  it  was  pre- 
viously, and  that  even  the  inhabitants  of  the  same  country  are  darker 
during  the  summer  than  in  winter. 

It  would  appear,  therefore,  to  be  very  possible  that  climate  alone, 
operating  through  many  ages,  would  be  sufficient  to  change  the  colour 
of  the  skin  from  white  to  all  the  varying  shades  of  red,  olive,  and  black, 
met  with  among  the  different  families  of  the  human  race. 

DESTRUCTION    AND    RENEWAL    OF    EPIDERMIS. 

The  epidermis,  like  the  epithelium,  is  constantly  undergoing 
destruction  and  renewal;  the  evidences  of  this  are,  however,  more 
obvious  and  striking  in  the  case  of  the  epidermis,  than  were  those 
adduced  in  proof  of  the  destruction  of  the  epithelium. 

Thus  the  destruction  of  the  epidermis  is  proved  by  a  variety  of  facts: 
By  the  gradual  disappearance  from  the  skin  of  indelible  stains,  such 
as  those  produced  by  nitrate  of  silver  or  nitric  acid. 


280  THE     SOLIDS. 

By  scraping  the  soles  of  the  feet  after  immersion  in  warm  water; 
the  white  and  powdery  material  which  is  obtained,  often  in  large 
quantities,  examined  with  the  microscope,  will  be  found  to  consist  of 
epidermic  scales. 

By  the  use  of  the  warm  bath;  floating  on  the  surface  of  the  water 
will  be  observed  more  or .  less  of  a  thin  and  whitish  scum ;  this 
consists  of  desquamated  epidermis. 

By  rubbing  the  moist  skin  with  a  rough  towel;  a  considerable 
amount  of  epidermis,  visible  to  the  naked  eye,  will  be  removed. 

The  skin  of  new-born  children  is  frequently  observed  to  be 
covered  with  a  white  and  soap-like  crust;  this,  examined  with  the 
microscope,  will  be  found  to  consist  of  epidermic  scales  mixed  up 
with  sebaceous  matter. 

The  last  proof  to  be  adduced  of  the  desquamation  of  the  epidermis 
is  one  derived  from  disease;  after  inflammation  of  the  skin,  whether 
that  of  erysipelas,  scarlatina  or  measles,  the  epidermis  peels  off,  a 
new  one  being  previously  formed  beneath  the  old. 

Among  many  of  the  amphibia  and  reptiles,  the  casting  of  the 
epidermis  is  a  periodical  occurrence;  in  man,  on  the  contrary,  it  is 
a  constant  and  gradual  process  normally,  although  it  is  also  occasion- 
ally periodic  from  disease. 

USES    OF    THE    EPIDERMIS. 

The  principal  uses  of  the  epidermis  are  threefold. 

The  first  and  chief  use  is  to  serve  as  a  protection  to  the  more 
delicate  parts  which  lie  immediately  beneath  it. 

The  second  is  to  prevent  the  too  rapid  dissipation  of  the  caloric  of 
the  system. 

The  third  use  has  reference  to  secretion.  It  is  evident,  however, 
that  the  importance  of  the  epidermis  as  a  secreting  organ  is  not  con- 
siderable, seeing  that  the  external  surfaces  of  the  body  do  not  require 
to  be  kept  moist,  to  the  same  extent  as  the  internal."  That  the  epider- 
mis does  not  very  actively  administer  to  secretion  might  be  inferred 
from  the*  transparency  of  the  fully-developed  cells,  the  faintness  of 
the  nuclei,  and  the  paucity  of  the  granules  contained  within  them. 

Epidermic  cells  are  also  capable  of  absorption,  a  fact  which  their 
change  of  colour  after  long  immersion  in  water  testifies. 

By  far  the  best  description  of  the  anatomy  of  the  epidermis  which 
has  fallen  under  my  notice  is  that  contained  in  the  admirable  chapter 
on  the  Anatomy  and  Physiology  of  the  Skin  attached  to  the  second 
edition  of  Mr.  Wilson's  work  on  the  Diseases  of  the  Skin. 


EPIDERMIS.  281 

EPIDERMIS. 

[In  the  paper  by  Mr.  Rainey,  referred  to  in  the  Appendix,  he  divides  the 
epidermis  into  two  layers,  the  superficial  layer  or  cuticle,  and  the  deep  layer 
or  rete-mucosum  of  other  authors.  The  deep  layer  rests  on  the  basement 
membrane  covering  the  papillae,  and  fills  up  the  grooves  between  them:  this 
layer  is  composed  of  nucleated  cells,  in  different  stages  of  development: 
those  below  being  very  small,  probably  only  cell  nuclei,  those  in  the  centre 
are  most  perfect,  and  those  above  approaching  the  condition  of  epidermic 
scales. 

The  superficial  layer,  or  cuticle,  extends  from  a  little  beyond  the  apices 
of  the  papillae  to  the  surface,  and  consists  of  flattened  cells,  which  have 
become  converted  into  scales.  These  scales  are  not  affected  by  action  of 
acetic  acid,  or  strong  solution  of  potassa,  while  by  these  reagents,  the 
nucleated  cells  are  entirely  destroyed. 

In  the  Appendix,  already  alluded  to,  the  author  has  referred  to  the  state- 
ment made  by  Mr.  Rainey,  that  no  true  duct  from  the  sudoriparous  glands 
exists  in  either  layer  of  the  epidermis,  the  passage  being  a  spiral  one 
through  the  epidermic  cells  and  scales.  ( Vide  Plate  LXXV1IL,  figs.  1,  2.) 
The  lining  of  the  sudoriparous  duct,  separated  with  the  epidermis  after 
maceration,  is  the  epithelial  lining  of  the  duct,  and  not  the  entire  duct,  as 
stated  by  some  writers. 

The  epidermis  may  be  readily  examined  in  thin  vertical  sections  made 
with  the  Valentin's  knife,  or  sharp  scalpel.  The  fresh  skin  will  be  found 
best  for  this  purpose,  and  those  portions  from  the  heel  or  palm  of  the  hand 
show  the  structure  best:  these  maybe  farther  dissected  with  the  needles 
under  the  microscope  and  in  water,  and  other  sections  may  be  treated  with 
acids  and  alkalies.  In  some  instances,  thin  sections  can  be  better  made 
when  the  skin  has  been  hardened,  and  rendered  more  firm  than  in  its 
natural  state. 

For  this  purpose,  a  strong  solution  of  carbonate  of  potassa,  diluted  nitric 
acid,  or  sulphuric  ether,  may  be  used.  When  sufficiently  thin  sections  can 
be  obtained  without  this  process,  the  structure  is  more  readily  made  out, 
and  with  a  good  Valentin's  knife,  this  is  not  usually  difficult  to  do.  By 
continued  maceration,  the  epidermis  may  be  separated  in  layers ;  this  pro- 
cess is  necessary  to  exhibit  well  the  deep  layer  or  rete-mucosum. 

When  desired,  sections  of  epidermis  may  be  mounted  in  fluid  for  preser- 
vation:  but  in  this  condition  they  will  be  of  little  service,  unless  to  show  the 
spiral  passages  and  external  orifices  of  the  sudoriparous  ducts.  The  rete- 
mucosum  is  also  best  preserved  in  fluid.] 


282  THE     SOLIDS. 


ART.   XI.   THE   NAILS. 


The  horny  appendages  of  the  feet  and  hands,  the  nails,  do  not 
constitute  a  distinct  structure  or  type  of  organization  in  themselves, 
but  are  merely  modifications  of  one  which  has  already  been  described, 
viz :  the  epidermis. 

Nails,  therefore,  consist  of  cells  similar  to  those  of  which  the 
epidermis  is  itself  constituted,  with  the  difference  that  they  are  harder, 
drier,  more  firmly  adherent  to  each  other,  and  that  in  the  majority 
the  nucleus  is  obliterated.     (See  Plate  XXV.) 

To  display  the  cellular  constitution  of  nails,  some  little  nicety  is 
required;  it  may  be  shown,  however,  in  the  thin  scrapings  of  any 
fragment  of  nail  submitted  to  the  microscope,  as  also  by  soaking  the 
nail  in  a  weak  alkaline  solution,  and  which,  acting  upon  and  dissolv- 
ing the  inter-cellular  and  uniting  substance,  sets  free  the  cells. 

The  cellular  structure  of  nails  may  also  be  shown,  even  without 
previous  preparation,  by  a  careful  examination  of  the  root  and  under 
surface  of  the  nail,  in  which  situations  young  and  nucleated  cells  may 
usually  be  detected. 

The  younger  nail  cells,  like  those  of  the  epidermis  in  the  coloured 
races,  contain  pigmentary  matter. 

Nails,  however,  are  not  simply  constituted  of  super-imposed  and 
adherent  cells,  but  these  are  regularly  disposed  in  layers  or  strata, 
each  of  which  probably  indicates  a  period  of  growth. 

These  layers,  marked  by  striae,  may  be  clearly  seen  on  any  thin 
section  of  nail,  whether  longitudinal  or  transverse;  they  do  not  appear 
to  follow  any  very  definite  course;  usually  in  a  longitudinal  slice, 
they  run  from  above,  downwards  and  forwards;  sometimes  they  are 
horizontal,  but  I  have  seen  instances  in  which  the  striae  were  directed 
obliquely  backwards,  in  place  of  forwards.  In  the  transverse  section, 
the  striae  are  less  strongly  marked,  and  run  usually  moi'e  horizontally. 
(See  Plate  XXV.)  Occasionally  they  are  seen  to  pass  in  opposite 
directions,  and  to  decussate.  I  am  disposed  to  think  that  the  one  set 
of  striae  visible  are  rather  apparent  than  real,  and  are  produced  by  the 
knife  employed  in  making  the  section. 

It  is  usually  easy  to  distinguish  the  superior  from  the  inferior  edge 
of  a  slice  of  nail;  the  former  will  generally  appear  quite  smooth, 
while  the  latter  will  be  rough  and  uneven.     (See  Plate  XXV.) 


THE      NAILS.  283 

Such  is  a  brief  sketch  of  the  structure  of  nails:*  their  form,  posi- 
tion, and  mode  of  connexion,  may  next  be  considered. 

Each  nail  may  be  said  to  be  quadrilateral  and  convex  from  side  to 
side,  as  it  is  also  very  generally  from  before  backwards ;  the  three 
posterior  margins  are  received  into  a  groove  formed  by  a  duplicature 
of  the  dermis  and  epidermis,  the  anterior  margin  alone  being  free. 
The  root  and  sides  of  the  nail,  the  former  consisting  of  about  one- 
fifth  of  its  extent,  are  intimately  attached  to  both  surfaces  of  the 
groove;  the  inferior  aspect  of  the  body  of  the  nail  is  likewise  firmly 
adherent  to  the  derm  beneath  it,  except  for  a  small  distance  at  its 
anterior  part. 

The  nail,  then,  is  attached  to  the  dermis  by  its  root,  and  by  a 
portion  of  its  inferior  surface;  this  attachment,  however,  is  scarcely 
to  be  considered  as  structural,  since  it  consists  of  a  mere  adaptation 
of  the  opposing  surfaces  of  the  dermis  and  nail.  The  surface  of  the 
dermis  upon  which  the  nail  rests,  it  is  known,  is  not  smooth,  but  is 
raised  into  papillae ;  to  these  the  nail  adapts  itself,  and  in  this  way  the 
two  become  intimately  united. 

It  is  in  this  manner,  also,  that  the  longitudinal  lines  observed  on 
most  nails  are  produced,  and  the  appearance  of  which  has  induced 
some  observers  to  entertain  the  idea  that  they  are  of  a  fibrous,  and 
not  a  cellular  constitution. 

Nails  are,  to  a  considerable  extent,  hygroscopic,  becoming  by  the 
imbibition  of  fluid  soft  and  yielding. 

DEVELOPMENT    OF    NAILS. 

Nails  are  developed  somewhat  differently  from  the  epidermis,  of 
which  we  have  stated  that  they  are  a  modification;  thus,  they  do  not 
increase  by  the  equal  development  of  new  cells  on  the  entire  of  their 
under  surfaces,  but  they  grow  from  a  point,  from  the  base  or  root  of 
the  nail. 

The  reality  of  this  mode  of  development  becomes  evident  from  the 
following  considerations: 

1st.  That  the  younger  nail  cells  are  found  principally  at  the  root 
of  the  nail. 

2d.  That   if  the   relative   situations   of   two   spots    or   stains   be 

*The  first  exact  description  of  the  nail  and  of  the  disposition  of  the  derm  which 
supports  it  was  given  by  Albinus  (Adnotal.  Acad.  lib.  ii.  1755,  p.  56),  but  Schwann 
showed  that  the  nail  had  a  lamellated  structure,  and  that  the  lamellaj  are  composed 
of  epidermic  scales.     (Mikroskopische  Unlersuchungen,  1839,  p.  90.) 


284 


THE     SOLIDS. 


observed,  it  will  be  seen  that  during  the  growth  of  the  nail,  they 
preserve  precisely  the  same  relation  with  each  other,  only  that  they 
gradually  approach  the  end  or  free  margin  of  the  nail,  which  at 
length  they  reach,  and  from  which  finally  they  are  worn  away.  This 
observation  proves  the  absence  of  interstitial  growth,  and  shows  that 
the  nail  increases  in  length  by  additions  made  to  the  root. 

Although  it  is  certain  that  the  longitudinal  growth  of  nail  occurs 
by  the  development  of  cells  at  the  root,  yet  it  is  also  evident  that  its 
thickness  is  increased  by  the  formation  of  new  cells  on  its  under 
surface,  where  they  may  usually  be  detected  with  the  microscope  in 
a  partially  developed  state.  This  double  development  explains  why 
the  nail  is  thinnest  at  the  root,  where  only  a  single  method  of  growth 
prevails. 

The  junction  of  the  root  with  the  body  of  the  nail  is  indicated  by 
a  semi-circular  line,  and  the  former  is  not  merely  thinner  than  the 
latter,  but  it  is  also  softer  and  whiter;  whiter  in  consequence  of  the 
subjacent  dermis  containing  in  that  situation  fewer  blood-vessels,  and 
its  papillae  being  smaller. 

From  the  pi-eceding  account  of  the  development  of  nails,  it  follows 
that  when  these  sustain  any  loss  of  substance  on  their  upper  surfaces, 
this  loss  is  never  repaired,  but  remains  without  alteration  until  it 
reaches  the  free  margin  of  the  nail. 

Epithelium,  epidermis,  nails,  and  some  other  structures  of  the  body, 
never  seem  to  attain  to  a  stationary  state;  they  are  throughout  the 
wThole  of  life  undergoing  a  process  of  development;  this,  in  the  case 
of  the  nails  of  man,  renders  the  interference  of  art  necessary  to 
remove  from  time  to  time  the  redundant  growth. 

It  is  probable,  however,  that  if  the  nails  were  not  cut,  but  allowed 
to  grow  at  will,  they  would  not  exceed  a  certain  length;  among  the 
Chinese,  who  do  not  pare  their  nails,  they  are  usually  about  two 
inches  long. 

Nails  doubtless  sustain  a  loss  of  substance  beyond  that  which  they 
experience  from  occasional  cutting,  as  from  friction  and  the  des- 
quamation of  the  cells  from  the  inferior  and  anterior  portion  of  each 
nail,  and  which  may  be  inferred  to  take  place  from  the  fact  that  the 
matter  which  accumulates  beneath  the  extremities  of  the  nails  is  to  a 
great  extent  made  up  of  epidermic  or  nail  cells. 

It  has  been  estimated  that  the  entire  body  of  a  nail,  from  the  root 
to  its  free  margin,  is  developed  in  from  two  to  three  months. 

The  third  month  of  intra-uterine  life  is  the  earliest  period  at  which 


THE     NAILS.  285 

the  nails  can  be  detected ;  they  then  consist  of  nucleated  cells,  and 
rather  resemble  soft  epidermis  than  the  hard  and  horny  texture  of 
fully-developed  nails. 

A  nail  which  has  been  once  entirely  destroyed  is  always  regen- 
erated in  a  very  imperfect  manner,  it  being  usually  seamy  and 
irregular  in  consequence  of  the  disturbance  and  injury  sustained  by 
the  adjacent  dermis,  and  the  markings  of  which  are  impressed  upon 
the  nail. 

Nails  are  subject  to  deformity  in  certain  chronic  maladies  of  the 
heart  and  lungs,  especially  in  cyanosis  and  phthisis.  It  has  been 
suggested  that  this  may  depend  upon  the  state  of  the  circulation  in 
the  vessels  of  the  dermis. 

The  various  modifications  of  nail  met  with  throughout  the  animal 
kingdom,  the  claws  of  birds  and  carnivora,  the  hoofs  and  horns  of 
ruminants,  have  essentially  a  similar  structure  to  the  nails  of  man. 
The  hoof  of  the  horse  and  of  some  other  animals  is  traversed  from 
above  downwards  by  the  spiral  ducts  of  the  sebaceous  glands. 


NAILS. 

[The  structure  of  nails  is  examined  in  thin  sections  and  scrapings,  placed 
in  the  field  of  the  microscope,  and  covered  with  a  drop  of  water,  or  oil  of 
turpentine. 

The  secreting  vessels  of  the  nail,  so  well  described  by  Mr-  Rainey  in  his 
paper  quoted  in  the  Appendix,  can  only  be  seen  after  injection,  and  the 
removal  of  the  nail.  A  foetal  subject  is  well  adapted  for  this  injection.  A 
hand  or  foot  of  an  adult  may  sometimes  be  so  well  filled  as  to  exhibit  these 
vessels. 

The  sections  or  scrapings  of  the  nail,  may  be  preserved  dry,  in  fluid,  or 
in  balsam,  the  choice  depending  on  the  thickness  of  the  specimen.  The 
injected  matrix,  &c,  is  best  preserved  in  fluid;  for  this  purpose,  alcohol 
and  water,  or  Goadby's  B-solution,  may  be  employed, 

See  Appendix,  page  541. 

Plate  LXXI.  represents  the  different  vessels  as  described  by  Mr.  Rainey.] 


THE     SOLIDS 


ART.   XII.  — PIGMENT    CELLS. 

Colouring  matter  is  found  in  the  animal  organization  in  two 
states,  either  diffused  throughout  the  fluid  contents  of  colourless  cells, 
as  in  fat  cells  generally,  but  especially  in  those  of  the  iris  of  birds, 
and  as  in  the  liver  cells,  and  red  blood  discs,  or  it  is  limited  to  the 
granules  contained  in  certain  peculiar  cells,  the  parietes  of  which  are 
also  colourless,  which  have  received  the  name  of  pigment  cells,  and 
which  we  are  now  about  to  describe. 

Pigment  cells  have  precisely  the  same  structure  as  those  of 
epithelium  and  epidermis,  the  description  of  which  has  just  been 
brought  to  a  conclusion;  that  is,  they  consist  of  cell  wall,  nucleus, 
cavity,  and  granules;  the  only  difference  between  the  two  is,  that  the 
granules  in  the  one  case  are  coloured,  and  in  the  other  colourless: 
as  may  be  inferred  from  their  similarity  of  organization,  a  similar 
mode  of  development  prevails  in  both.* 

All  the  varieties  of  colour  of  the  eye  and  of  the  skin,  observed 
among  the  different  members  and  families  of  the  human  race,  depend 
upon  the  number  of  pigment  cells  and  the  shade  and  intensity  of  the 
colouring  matter  enclosed  within  the  pigmentary  granules;  the  deeper 
the  colour,  the  more  abundant  the  pigment  cells,  and  the  greater  the 
depth  of  colouring  contained  in  the  granules;  thus,  of  course,  the 
pigment  cells  scattered  beneath  the  epidermis  of  the  Ethiopian  are 
far  more  numerous  than  those  found  beneath  that  of  the  white  race, 
and  the  colouring;  matter  of  the  granules  is  doubtless  also  darker. 

In  the  white,  however,  a  greater  or  less  number  of  pigment  cells  is. 
almost  invariably  found  in  certain  situations,  as  in  the  eye,  on  the 
internal  surface  of  the  choroid,  and  the  posterior  aspect  of  the  iris 
and  ciliary  processes,  also  between  the  sclerotic  and  choroid;  in  the 
skin  at  certain  localities  where  it  is  placed  beneath  the  dermis  and 
epidermis,  as  in  the  areola  round  the  nipples,  especially  of  women, 
and  about  the  perinaeum  and  genital  organs. 

In  the  black  races,  pigment  cells  follow  a  similar  distribution  in 

*  Mondini  (Comment.  Bonon,  t.  vii.  1791,  p.  29,)  was  the  first  observer  who  made 
accurate  microscopic  observations  on  the  pigment  of  the  eye.  He  stated  that  the 
pigment  is  not  simply  mucus,  but  a  true  membrane  formed  of  globules  disposed  in 
quincunx.  The  son  all  but  completed  the  work  which  the  parent  began :  he  found 
that  each  globule  is  made  up  of  little  black  points.  Finally,  Kieser  (Be  Anamorphosi 
Oculi,  1804,  p.  34,)  described  the  pigmentary  membrane  as  a  cellular  tissue  containing 
corpuscles. 


PIGMENT     CELLS.  2S7 

the  eye;  but  beneath  the  epidermis,  as  also  under  the  nails,  they 
form  a  continuous  stratum  composed  of  super-imposed  layers  of  cells. 

There  are  yet  other  situations  in  which  pigment  cells  have  been 
encountered :  thus,  Valentin*  has  signalized  the  occurrence  of  pig- 
mentary ramifications  in  the  cervical  portion  of  the  pia  mater,  to 
which  they  impart  a  blackness  perceptible  to  the  unaided  sight. 

Again,  Wharton  Jonesf  has  described  a  thin  but  evident  layer  of 
brown  pigment  in  the  membranous  labyrinth  of  the  ear  of  man.  It 
has  been  observed  in  other  mammalia,  in  which  it  is  still  more 
marked,  in  the  same  situation,  by  Scarpa,  Comparetti,  and  Breschet.  J 

The  brown  spots,  known  by  the  name'  of  freckles,  with  which  the 
faces  of  most  persons  are  more  or  less  covered  in  summer,  are  due  to 
a  development  of  pigment  cells. 

A  development  of  pigmentary  matter  frequently  takes  place  as  the 
consequence  of  disease;  thus,  it  is  of  common  occurrence  to  meet 
with  growths  either  entirely  or  in  part  composed  of  pigment  cells,  the 
tumours,  with  the  proper  structure  of  which  it  usually  thus  inter- 
mingled, being  those  of  cancer  or  medullary  fungus. 

The  nature  of  the  pigment-like  matter  found  in  the  lungs  and 
bronchial  glands  of  aged  persons  and  animals  has  been  the  subject  of 
much  discussion ;  nor  has  it  been  as  yet  decided  whether  it  be  true 
pigment,  or  merely  a  deposition  of  carbon.  Pearson§  maintained 
the  opinion  that  the  colouring  matter  is  the  powder  of  carbon,  since 
neither  chlorine  nor  the  mineral  acids  act  upon  it. 

In  those  remarkable  lusus  natures,  Albinoes,  there  would  appear  to 
be  an  absence  of  pigmentary  granules  in  all  parts  of  the  body,  even 
in  the  eye:  the  pigment  cells  themselves  are  stated  to  exist,  but  to  be 
wanting  in  their  characteristic  coloured  contents. 

Pigment  cells  do  not  present  the  same  size,  form,  and  character 
wherever  they  are  encountered. 

Thus,  those  of  the  choroid  are  adherent,  large,  flattened,  polygonal, 
mostly  hexagonal,  with  clear  nuclei  and  margins;  occasionally,  how- 
ever, it  happens  that  both  nuclei  and  cell  wall  are  obscured  by  the 
number  and  disposition  of  the  contained  granules :  the  cells  are  mostly 
of  uniform  size  as  well  as  shape,  in  consequence  of  which  regularity 
they  form  a  very  beautiful  microscopic  object;  sometimes,  however, 

*  Verlaufund  Enden  der  Nerven,  p.  43. 

f  Article  Hearing  in  the  Cyclopaedia  of  Anatomy  and  Physiology,  t.  ii.  p.  529. 

I  Rtcherches  sur  VOrgane  de  VOiiie  de  V Homme,  Paris,  1836,  in  4to. 

\  Philosophical  Transactions,  1813,  pi.  ii.  p.  159 


^Sy  THE     SOLIDS. 

one  cell  is  observed  to  be  larger  than  the  rest,  octagonal,  and  sur- 
rounded  by  a  number  of  cells  of  smaller  size  than  ordinary,  and 
mostly  pentagonal. 

According  to  Henle,*  the  contained  granules  are  situated  in  the 
posterior  part  of  each  cell,  while  the  nucleus  is  placed  in  its  anterior 
division ;  it  is  this  arrangement  which  allows  of  the  nucleus  being  so 
clearly  seen ;  in  those  cases,  however,  in  which  the  nucleus  is 
obscured,  acetic  acid  will  frequently  bring  it  into  view;  this,  if  con- 
centrated, will  dissolve  the  cell  wall,  set  free  the  granules,  and  leave 
the  nucleus. 

Schwann  states  that  he  has  seen  the  pigmentary  granules  in  the 
cells  of  the  choroid  in  active  motion. 

The  cells  of  the  choroid  form  by  their  adherence  a  membrane  resem- 
bling the  most  regular  and  beautiful  mosaic  pavement  in  miniature. 

The  pigment  cells  of  the  posterior  face  of  the  iris  and  ciliary 
processes  are  smaller  than  those  of  the  choroid,  are  for  the  most  part 
round,  or  approach  that  form,  and  so  filled  with  the  corpuscles  that 
the  nucles  and  margin  of  the  cell  is  not  usually  visible. 

In  the  skin,  the  pigment  cells  are  placed  between  the  dermis  and 
epidermis ;  they  do  not  there  form  a  layer  of  equal  thickness,  but 
accumulate  in  the  depressions  left  between  the  papilla?,  forming  many 
super-imposed  layers,  while  on  these  they  are  spread  out  in  a  single 
thin  layer,  and  are  often  much  scattered.  It  is  to  this  circumstance, 
as  well  as  the  thickness  of  the  epidermis,  and  the  state  of  repletion  of 
the  cells,  that  the  varying  shades  of  the  colour  of  the  skin  of  the 
same  individual  depend.  In  the  negro,  the  cells  resemble  much  in 
form  those  of  the  choroid,  being  either  perfectly  hexagonal,  polygonal, 
or  irregularly  rounded ;  the  nucleus  can  be  well  seen  in  those  cells 
which  are  less  filled. 

Among  the  white  race,  the  pigment  cells  in  those  situations  in 
which  they  occur  beneath  the  skin  are  fewer  in  number,  smaller, 
more  rounded,  and  frequently  resemble  little  masses  of  corpuscles 
rather  than  distinct  cells;  nevertheless  it  is  even  here  sometimes 
possible  to  distinguish  the  nucleus  and  cell  wall. 

There  exists  between  the  internal  face  of  the  sclerotic  and  the 
external  of  the  choroid  a  fibrous  tissue  of  a  brown  colour;  this,  when 
these  two  coats  of  the  eye  are  separated,  remains  attached  in  part  to 
the  one,  and  in  part  to  the  other;  that,  however,  which  adheres  to 
the  sclerotic  has  received  a  distinct  name,  and  is  called  lamina  fusca. 

*  Anat.  Gen.  vol.  vi.  p.  295. 


PIGMENT     CELLS.  289 

Now,  the  colour  of  this  layer  is  due  to  the  presence,  scattered  among 
the  fihres,  of  pigment  cells  of  a  very  peculiar  form  and  construction ; 
they  are  mostly  very  irregular  in  size  and  shape,  are  marked  with  a 
clear  central  spot,  which  indicates  the  locality  of  the  nucleus,  and 
from  the  margin  of  many  of  them  proceed  filamentous  processes  of 
variable  number  and  size,  and  the  extreme  points  of  which  are  mostly 
colourless,  and  are  not  dissolved  by  acetic  acid. 

Pigment  cells  of  analogous  construction  exist  on  the  external  surface 
of  the  choroid,  and  also  on  the  cervical  portion  of  the  pia  mater. 

Mixed  up  with  perfect  pigment  cells  a  greater  or  less  number  of 
pigment  granules  are  always  observed ;  these  are  among  the  smallest 
objects  in  nature,  and,  on  account  of  their  minuteness,  it  is  in  them 
that  molecular  action  in  all  its  activity  is  best  seen:  they  are  not 
spherical  in  form,  but  are  flattened,  so  that  they  appear  as  discs,  lines, 
or  points,  according  as  the  surface,  side,  or  end  presents  itself  to  the 
eye  of  the  observer. 

It  is  probable  that  it  is  by  means  of  these  granules  that  pigment 
cells  are  multiplied. 

Climate,  and  particular  states  of  the  system,  as  pregnancy,  have 
much  effect  in  increasing  the  amount  of  pigmentary  matter  beneath 
the  skin;  from  the  latter  cause,  the  areolae  around  the  nipples 
frequently  become  of  a  deep  chocolate  colour.  Of  the  influence  of 
the  former,  it  is  scarcely  necessary  to  cite  examples :  it  may  be 
remarked,  however,  that  freckles  are  due  to  the  development  of  pig- 
ment cells,  brought  about  by  the  action  of  the  summer's  sun. 

This  augmented  development  of  pigment  cells  may  be  rationally 
explained  by  the  increased  determination  of  blood  to  the  dermis  of 
the  breast  from  increased  activity  of  function  in  that  organ  during 
pregnancy,  and  to  the  general  surface  from  the  effect  of  the  sun's  heat. 

It  is  questionable  whether  all  the  varieties  of  colour  of  the  human 
species  have  not  originated  in  climateric  causes,  operating  through 
many  ages. 

It  may  also  be  questioned  whether  pigment  cells  are  not  susceptible 
of  being  developed  into  those  of  the  epidermis.  If  the  epidermis  of 
a  negro,  raised  from  the  surface  by  means  of  a  vesicatory,  be  exam- 
ined with  the  microscope,  it  will  be  noticed  that  the  most  external  cells 
contain  a  considerable  amount  of  colouring  matter,  which,  as  this 
resides  in  solid  granules  and  not  in  a  fluid,  it  is  difficult  to  suppose 
had  entered  the  cells  by  endosmosis. 

Pigment  cells  are  capable  of  regeneration,  in  a  part  in  which  they 

19 


290  THE     SOLIDS. 

have  been  destroyed:  it  is  necessary,  however,  that  the  subjacent 
dermis  be  not  too  deeply  injured ;  the  cicatrices  remain  for  a  consid- 
erable time  nevertheless  without  colour. 

The  skin  of  the  children  of  negro  women  does  not  acquire  its  full 
depth  of  colouring  for  some  days  after  birth. 

Pigment  cells  are  developed  at  a  very  early  period  of  intra-uterine 
life.  The  uses  of  pigment  in  the  skin  are  not  well  understood;  that 
in  the  eye  is  doubtless  of  importance  in  the  discharge  of  the  functions 
of  that  organ:  it  is  known  that  the  Albinoes,  in  whom  it  is  either 
absent  or  exists  but  in  small  quantities,  are  incapable  of  supporting  a 
strong  light. 

Pigment  cells  of  particular  forms  occur  among  some  of  the  lower 
animals.  Those  of  the  internal  surface  of  the  choroid  of  fishes  and 
birds,  situated  in  front  of  the  ordinary  coloured  cells,  have  the  form 
either  of  short  sticks  or  clubs.  The  argentine  pigment  of  the  iris 
and  peritoneum  of  fishes  is  composed  of  elongated  corpuscles.  The 
pigment  cells  placed  beneath  the  epidermis  of  the  frog  are  for  the 
most  part  stellate. 


PIGMENT   CELLS. 

[Pigment  cells  are  most  readily  studied  on  being  detached  from  the 
choroid  coat  of  the  eye,  by  means  of  a  fine  needle.  On  rupturing  the  cells, 
the  pigmentary  matter  escapes ;  and  with  a  high  power  of  the  microscope, 
numerous  black  or  brown  molecules  will  be  observed.  These  molecules 
measure  from  TTin  to  g  jio  o  of  an  incn  in  diameter. 

These  cells  may  also  be  studied  with  advantage  in  the  cuticle  of  the 
negro,  which  may  be  detached  after  slight  maceration,  and  also  in  the  skin 
of  the  frog. 

The  pigment  cells  in  the  frog,  will  be  found  to  consist  of  long,  irregular, 
jagged  processes. 

Cells  containing  pigmentary  matter  are  well  preserved  in  the  flat  cell 
with  fluid.] 


HAIR.  291 


ART.    XIII.  — HAIR. 

We  now  come  to  the  description  of  another  epidermic  modifica- 
tion, viz:  hairs;  these,  however,  are  much  more  complex  in  their 
structure  than  any  which  have  been  hitherto  described,  and  are  less 
obviously  derived  from  the  epidermis. 

As  in  the  case  of  most  of  the  solids  described  in  this  work,  we  shall 
first  discuss  the  different  particulars  relating  to  form  and  size,  and  next 
proceed  to  the  description  of  structure. 

FORM    OF    HAIRS. 

Hairs  consist  of  two  parts,  a  root  and  a  stem :  in  speaking  of  the 
form  of  hairs,  reference  is  made  to  the  latter.  Hairs,  then,  are  elon- 
gated, and  more  or  less  cylindrical  developments  of  the  epidermis. 
They  depart,  however,  in  most  cases,  from  the  character  of  a  true 
cylinder  in  two  respects;  first,  they  are  not  perfectly  spherical,  but 
are  seen  to  be,  when  viewed  transversely,  either  oval,  flattened,  or 
reniform  (see  Plate  XXIX.) ;  and  secondly,  they  are  not  of  equal 
diameter  throughout,  being  thickest  at  about  the  junction  of  the  lower 
and  middle  thirds  of  the  stem,  of  smaller  diameter  from  this  part  down- 
wards towards  the  root,  and  still  more  reduced  in  size  as  the  free 
extremity  is  approached,  and  which,  in  a  hair  which  has  not  been 
recently  cut,  terminates  in  a  point,  the  diameter  of  which  is  frequently 
several  times  less  than  that  of  the  more  central  parts  of  the  shaft. 
(See  Plate  XXIX.) 

This  form  is  best  seen  in  hairs  of  medium  length,  as  those  of  the 
whiskers,  eyebrows,  axillae,  and  pubis,  in  which  also  the  flattened  and 
oval  shapes  are  principally  detected. 

The  hairs  which  approach  most  closely  the  cylindrical,  are  those  of 
the  scalp. 

Henle*  makes  the  interesting  statement,  that  the  curling  of  hair 
depends  upon  its  form,  and  that  the  flatter  the  hair,  the  more  it  curls, 
the  flat  sides  being  directed  exactly  towards  the  curve  described. 
From  this  it  follows,  that  the  hair  of  negroes  would  exhibit  in  a  very 
marked  manner  this  flattened  form. 

*  Anat.  Gen.,  vol.  vi.  p.  314. 


292  THE     SOLIDS. 


SIZE    OF    HAIRS. 


Hairs  differ  remarkably  in  size,  both  as  regards  length  and  breadth: 
they  differ  not  merely  in  different  individuals,  in  different  localities 
'in  the  same  person,  but  also  in  any  one  given  situation,  as  the  scalp 
or  pubis. 

The  hairs  of  the  scalp  are  the  longest;  those  of  the  scalp  of  women 
are  many  times  longer  than  those  of  the  same  part  in  man,  and  accord- 
ing to  the  measurements  of  Mr.  Wilson,  they  are  also  thicker.  Next  in 
length  come  the  hairs  of  the  chin  of  man.  Among  women,  instances 
have  been  known  of  the  hair  extending  from  the  scalp  to  below  the 
feet,  and  the  beard  of  man  not  unfrequently  reaches  to  the  waist. 

The  shortest  and  smallest  hairs  are  those  covering  the  general  sur- 
face of  the  body,  and  which  are  reduced  to  mere  down  (lanugo). 

The  thickest  hairs  of  the  body  are  those  of  the  whiskers,  chin,  pubis, 
and  axilla?;  the  finest,  those  distributed  over  the  general  surface;  the 
hairs  of  the  scalp  are  of  intermediate  diameter. 

The  hairs  of  children  are  finer  than  those  of  adults,  and  those  of 
the  head  of  men  than  those  of  women. 

It  cannot  be  doubted  but  that  frequent  cutting  and  shaving  of  the 
hair  tends  to  increase  its  thickness. 


STRUCTURE    OF    HAIR. 


Each  hair  admits  of  division  into  two  parts,  the  root  and  stem; 
and  each  of  these,  again,  allows  of  still  further  sub-division  :  thus,  the 
root  consists  of  the  prolongation  of  the  hair  proper,  or  stem,  termi- 
nating in  an  expanded  portion,  which  has  been  termed  the  bulb,  and 
of  a  double  sheath;  the  stem  also  is  divisible  into  cortex,  medulla,  and 
intervening  fibrous  portion,  which  constitutes  the  chief  bulk  of  the 
hair.     (See  Plates  XXVIII.  and  XXIX.) 

These  divisions  of  the  root  and  stem  of  hairs  suggests  its  comparison 
to  a  tree,  the  stem  of  which  also  resolves  itself  into  cortex,  medulla, 
and  intervening  woody  or  fibrous  substance.  The  comparison  is  also 
heightened  by  the  similar  relation  in  which  both  stand  to  the  parts 
around  them,  viz :  the  soil  in  the  case  of  the  tree,  and  the  dermis  in 
that  of  the  hair. 

ROOT    OF    HAIR. 

We  will  first  describe  the  root,  because  it  is  the  source  from  which 
the  hair  is  developed:  this,  as  already  noticed,  consists  of  two  parts, 
the  sheath  and  the  bulb. 


HAIR.  293 

The  Bulb. — The  bulb  is  the  expanded  and  basal  portion  of  the  stem 
of  each  hair :  it  is  usually  two  or  three  times  the  diameter  of  the  hair 
itself,  and  is  sometimes  excavated  below :  it  is  constituted  of  granular 
cells,  which  are  either  circular,  angular,  or  elongated  in  form ;  the 
spherical  cells,  form  the  extremity  of  the  bulb,  the  polygonal  ones  its 
surface,  and  the  elongated  cells  are  placed  above  the  spherical  ones, 
of  which  they  are  modifications,  and  beneath  the  angular  cells  of  the 
surface  of  the  bulb.  Acetic  acid  will  be  found  useful  in  displaying 
the  cellular  structure  of  the  bulb. 

In  healthy  hairs  this  bulbous  portion  of  the  stem  is  always  coloured, 
which  is  not  the  case  with  gray  hairs.     (See  Plate  XXVIII.) 

The  part  of  the  stem  of  the  hair  immediately  above  the  bulb,  and- 
included  within  its  sheath,  exhibits  the  structure  of  the  body  of  the 
stem  itself,  being  divisible  into  scaly  cortex,  fibrous  intervening  sub- 
stance, and  granular  medulla.* 

Sheath. — The  bulb  and  lower  portion  of  the  stem  of  the  hair  is 
included  in  a  sheath  consisting  of  two  distinct  layers,  an  outer  and  an 
inner.     (See  Plate  XXVIII.  fig.  1.) 

The  outer  layer  is  an  inversion  of  the  epidermis :  it  first  merely 
encircles  the  portion  of  the  stem  of  the  hair  beneath  the  level  of  the 
epidermis :  it  next  surrounds  the  inner  layer  of  the  sheath,  to  which  it 
soon  becomes  intimately  adherent;  finally,  it  forms  a  cul-de-sac  around 
the  bulb  of  the  hair. 

The  fact  of  the  inverted  sheath  of  the  epidermis  forming  a  pouch 
around  the  bulb  of  the  hair,  may  be  inferred  from  the  circumstance, 
that  when  the  epidermis  peels  off  as  the  result  of  decomposition,  the 
hairs  usually  come  away  entire  with  it ;  its  continuation,  moreover, 
around  the  bulb  may  be  shown  in  transverse  sections  of  the  skin  of 
the  axillae  and  whiskers,  in  which  the  hairs  penetrate  into  the  sub- 
cutaneous fatty  substance.     (See  Plate  XXVIII.  fig.  1.) 

This  outer  layer  is  colourless,  is  possessed  of  considerable  thickness, 
and  is  evidently  made  up  of  granular  cells  similar  to  young  epider- 
mic cells. 

In  most  hairs,  whether  coloured  or  uncoloured,  which  have  been 
forcibly  removed  from  the  skin,  this  outer  layer  is  usually  torn  across, 
the  rupture  occurring  almost  invariably  at  a  little  distance  from  the 
bulb  of  the  hair:  the  root  of  the  hair,  then,  below  this  breach  of  con- 
tinuity, consists  only  of  the  inner  layer  of  the  sheath  and  of  the  stem 
of  the  hair ;  and  at  this  situation  the  root,  to  the  naked  eye,  appears 

*  See  Appendix,  p.  549. 


294  THE     SOLIDS. 

contracted:  this  is,  however,  but  an  appearance,  the  result  of  the 
absence  of  the  outer  layer,  and  of  the  expansion  of  the  stem  into  the 
bulb.     (See  Plate  XXVIII.  fig.  2.) 

The  inner  layer  of  the  sheath  is  an  eversion  or  revolution  of  the 
epidermis,  and  is  an  offset  or  continuation  of  the  outer  layer,  com- 
mencing at  the  lower  part  of  the  bulb :  it  is  colourless,  possessed  of 
considerable  thickness,  its  diameter  being  about  one-third  of  that  of 
the  stem  of  the  hair  in  its  thickest  part :  it  tears  readily  in  the  longi- 
tudinal direction  with  a  somewhat  uneven  fracture ;  and  hence  may- 
be inferred  to  be  of  a  fibrous  constitution,  as  may  be  shown  to  be  the 
case :  its  inner  surface  is  marked  with  reticulated  lines,  the  impressions 
of  the  cortical  scales  of  the  shaft  of  the  hair. 

This  inner  layer  is  not  of  equal  diameter  throughout,  but  tapers 
gradually  from  below  upwards:  it  is  well  defined  both  internally  and 
externally,  except  where  it  comes  in  contact  with  the  bulb  internally, 
with  which  its  inner  edge  or  surface  becomes  incorporated;  above,  it 
terminates  in  a  thin  border  at  a  little  distance  below  the  level  of  the 
skin.     (See  Plate  XXVIII.  fig.  1.) 

The  outer  layer,  although  adherent  to  the  inner  at  its  lower  part, 
does  not  become  incorporated  with  it :  the  latter,  except  at  the  point 
indicated,  preserves  every  where  its  independence  and  individuality. 
The  two  layers,  it  will  thus  be  seen,  might  with  much  convenience 
have  been  described,  as  two  distinct  sheaths,  an  inner  and  an  outer: 
to  do  so,  would  be,  however,  to  lose  sight  in  some  measure  of  the 
similar  origin  and  nature  of  the  two. 

In  the  fact,  however,  of  the  inner  sheath  exhibiting  a  fibrous  struc- 
ture, and  of  its  incorporation  with  the  bulb,  it  would  appear  to  have 
more  structural  affinity  with  the  fibrous  portion  of  the  stem  of  the 
hair  itself  than  with  the  outer  layer  or  cellular  sheath. 

This  inner  layer  might  be  appropriately  termed  the  "modelling 
sheath,"  since  it  doubtless  regulates  the  form  and  dimensions  of  the 
shaft  of  the  hair,  the  substance  of  which  when  first  developed  is  soft 
and  plastic.  Henle  describes  the  inner  layer  as  fenestrated :  this 
structure  I  have  never  seen  exhibited. 

Shaft  of  the  Hair. 

The  stem  or  shaft  of  the  hair  is  divisible,  as  already  observed,  into 
cortical,  medullary,  and  fibrous  portions. 

Cortex. — The  cortical  part  of  the  hair  consists  of  a  layer  of  scales, 
imbricated  upon  each  other  after  the  manner  of  tiles  upon  the  roof 


HAIR.  295 

of  a  house.  (See  Plate  XXIX.)  These  scales  are  best  seen  in  the 
larger  hairs  of  the  whiskers  and  pubis,  and  in  the  small  downy  hairs; 
they  are  smaller  than  the  ordinary  cells  of  epidermis,  and  are  rarely 
seen  to  be  nucleated.  Maceration  of  the  hair  in  sulphuric  acid 
causes  them  to  fall  off,  and  in  this  way  their  size,  form,  and  structure, 
may  be  satisfactorily  studied. 

The  scales  are  absent  from  the  points  of  the  finer  hairs.  In  con- 
sequence of  their  imbrication  upon  each  other,  their  little  thickness, 
and  of  the  double  contour  presented  by  their  free  edges,  they 
frequently  convey  the  appearance  rather  of  anastomosing  fibres 
running  round  the  hair  than  of  distinct  scales. 

A  hair  rolled  between  the  fingers  always  advances  in  a  given 
direction,  viz:  towards  the  apex:  this  results  in  part  from  the  taper- 
ing form  of  the  hair,  and  partly  from  the  more  or  less  spiral  disposition 
of  the  scales. 

Fibrous  Layer. — The  fibrous  portion  of  the  stem  of  the  hair 
constitutes  its  chief  substance  and  bulk,  forming  two-thirds  of  the 
entire  diameter,  one-third  on  each  side  of  the  medulla.  In  hairs  which 
are  not  too  dark,  the  constituent  fibres  may  be  seen  in  situ:  they  are 
most  palpably  brought  into  view  either  by  scraping  the  hair  with  a 
knife  or  by  crushing  it  after  masceration  in  sulphuric  acid :  they  are 
also  best  seen  in  the  larger  hairs  and  near  the  centre  of  the  shaft. 

Henle  describes  the  fibres  as  flat,  with  uneven  edges,  and  is  in 
doubt  as  to  whether  they  are  branched  or  not.  To  my  observation 
they  appear  much  smaller  than  they  are  stated  to  be  by  Henle,  and 
are  spherical  and  simple.     (See  Plate  XXIX.) 

These  fibres  have  a  cellular  origin,  and  are  formed  by  the  elongation 
of  the  inner  cells  of  the  bulb,  in  which  their  gradual  extension  into 
perfect  fibres  may  be  traced. 

•  They  are  stated  by  most  observers  not  to  extend  to  the  extreme 
point  of  the  hair;  and  the  same  statement  is  likewise  made  in  refer- 
ence to  the  medullary  canal  and  cortical  scales.  Of  what,  then,  it 
may  be  fairly  asked,  is  the  point  of  the  hair  constituted,  since  every 
structure  entering  into  the  formation  of  the  shaft  is  denied  to  it? 
The  assertion  that  the  fibres  do  not  extend  to  and  form  the  apex  of 
the  hair  is  evidently  erroneous.  In  the  examination  of  the  points 
of  a  number  of  hairs  which  have  not  been  recently  cut,  fibres,  often 
separated  from  each  other  and  loose,  will  frequently  be  detected. 
(See  Plate  XXIX.) 

The  whole  of  the  fibres  of  the  stem,  however,  do  not  extend  its 


296  THE     SOLIDS. 

entire  length,  the  majority  terminating  long  before  the  extremity  is 
attained;  and  it  is  to  this  fact  that  the  attenuated  form  of  the  hair 
is  attributable.  In  some  hairs  the  fibres  are  seen  to  terminate  at 
regular  distances,  their  points  describing  transverse  lines  on  the  stem 
of  the  hair. 

The  splitting,  of  such  common  occurrence  in  hairs  which  are 
allowed  to  attain  an  excessive  length,  is  due  to  a  separation  of  the 
fibres  from  each  other. 

The  fibrous  portion  in  young  and  healthy  hairs  is  coloured. 
Medullary  Canal  and  Medulla. — In  most  hairs  which  are  not  of 
too  deep  a  colour  a  medullary  canal  may  be  detected  running  up  the 
centre.  This  commences  in  the  upper  portion  of  the  bulb,  runs 
along  the  shaft,  but  ceases  as  it  approaches  the  apex:  its  diameter 
varies  with  that  of  the  hair  itself,  but  usually  bears  the  proportion  of 
a  third  of  its  thickness.     (See  Plates  XXVIII.  and  XXIX.) 

Henle  is  uncertain  whether  this  canal  is  lined  by  a  distinct  mem- 
brane or  not,  but  inclines  to  the  opinion  that  it  is  so. 

The  medulla  or  contents  of  this  canal  exhibit  a  granular  appear- 
ance, and  are  made  up  of  pigment  granules,  a  few  perfect  pigmentary 
cells,  and  particles  of  coloured  oil ;  it  is  therefore  in  the  medulla  that 
the  greatest  amount  of  colouring  matter  of  the  hair  is  situated.  (See 
Plate  XXVIII.  fig.  1.) 

At  the  very  commencement  in  the  bulb  of  the  hair,  the  medulla 
has  distinctly  a  cellular  origin. 

In  young  and  healthy  hairs  it  is  also  continuous  throughout  the 
entire  extent  of  the  medullary  canal;  in  old  and  discoloured  hairs, 
on  the  contrary,  its  continuity  is  frequently  interrupted  by  distinct 
intervals,  and  it  only  partially  fills  the  cavity  of  the  canal  .even 
where  it  is  present. 

The  medullary  canal  and  medulla  is  best  seen  in  the  larger  hairs, 
which  are  not  of  too  deep  a  colour,  and  in  gray  hairs:  in  the  fine 
and  downy  hairs  of  the  general  surface  of  the  body,  the  canal  and 
its  contents,  as  a  necessary  consequence,  are  almost  entirely  absent. 
In  some  rare  instances,  two  medullary  canals  have  been  observed 
in  the  same  hair.  In  the  sable,  the  medulla  has  a  distinctly  cellular 
structure  throughout.* 

*  The  first  accurate  observations  on  hair  were  made  by  Hook,  Micographia,  1667, 
Obs.  32.  tab.  v.  fig.  2.,  and  Leeuwenhoek,  Opera,  t-  iv.  p.  46. 


HAIR.  297 


FOLLICLE    OF    THE    HAIR. 


Each  hair  is  implanted  in  a  distinct  depression  in  the  dermis,  the 
base  of  which  especially  is  freely  supplied  with  nutrient  vessels:  this 
depression  is  also  lined  by  an  invagination  of  the  epidermis,  and 
which  becomes  ultimately  the  outer  layer  of  the  sheath  of  the  root 
of  the  hair  as  already  described.     (See  Plate  XXVI.  fig.  3.) 

Between  this  layer,  however,  and  the  shaft  of  the  hair  for  a  short 
distance  before  it  rises  above  the  level  of  the  skin,  a  space  or  cavity 
is  left;  into  this  space  the  canals  of  one  or  more  sebacious  ducts 
generally  open,  and  in  it  also  entozoa  frequently  develope  themselves. 

It  sometimes  happens  that  two  or  more  hairs  are  contained  in  the 
same  follicle  (see  Plate  XXVI.  fig.  3) :  in  these  cases,  however,  each 
hair  has  a  distinct  modelling  sheath.  In  some  animals,  the  location 
of  a  number  of  hairs  in  one  sheath  is  the  ordinary  mode  of  arrange- 
ment; in  the  pig,  for  example,  the  hairs  are  usually  thus  associated  in 
three's,  as  also  occasionally  in  man. 

The  hair  follicle  or  crypt  is  best  seen  by  examining  thin  vertical 
slices  of  the  skin. 

The  length  of  the  hair  follicle  and  the  consequent  depth  of  implant- 
ation of  the  hair  varies,  but  is  often  equal  to  the  twelfth  or  sixteenth 
of  an  inch ;  the  hairs  of  the  head,  of  the  whiskers,  of  the  pubis,  and 
of  the  axillae,  penetrate  into  the  sub-cutaneous  cellular  tissue;  those  of 
the  eyelids  and  ears,  to  the  subjacent  cartilages :  the  roots  of  hairs  in 
genera],  however,  do  not  penetrate  beyond  one-half  the  depth  of  the 
corium,  in  the  substance  of  which  they  are  buried. 

It  is  usually  stated  that  the  bottom  of  the  follicle  is  occupied  by  a 
papilla  furnished  with  blood-vessels  and  nerves,  on  which  the  bulb  of 
the  hair  immediately  rests ;  and  that  it  is  owing  to  this  papilla  that 
the  base  of  the  bulb,  when  removed,  exhibits  a  concavity.  This 
description,  in  the  case  of  tactile  hairs,  may  be  correct,  but  is  surely 
not  so  when  applied  to  hairs  in  general.  Each  hair  does  indeed  rest 
upon  a  papilla,  but  it  is  one  which  is  destitute  of  blood-vessels  and 
nerves,  and  which  is  cut  off  from  all  direct  vascular  communication 
by  the  cul-de-sac  formed  by  the  outer  lamina  of  the  sheath.  This 
papilla  may  be  described  as  a  compound  cellular  vesicle,  and  is 
probably  the  true  germ  of  the  hair;  it  is  on  it  that  the  bulb  of  the 
hair  is  situated,  and  which  occasions  the  depression  which  this 
generally  displays  when  it  has  been  forcibly  extracted.  This  germ 
is  best  seen  in  gray  and  light-coloured  hairs. 


298  THE     SOLIDS 


GROWTH    OF   HAIR. 

The  growth  of  hair  takes  place  at  the  root,  and  is  the  effect  of  the 
development  of  new  cells,  which  is  continually  in  progress  in  the  bulb, 
and  which  afterwards  become  modified  into  those  of  the  scaly  cortex 
and  fibrous  stem ;  these  new  cells,  coming  behind  the  older  ones,  contin- 
ually press  them  forwards,  and  thus  occasion  the  elongation  of  the  hair. 

But  the  elongation  of  each  hair  takes  place  in  a  manner  very  differ- 
ent from  that  just  mentioned,  not  from  the  development  of  new  cells, 
but  by  the  gradual  elongation  and  extension  of  the  cells  already 
formed  after  they  have  quitted  the  bulb,  and  when  they  come  to  form 
the  shaft  of  the  hair.  This  mode  of  elongation — it  can  scarcely  be 
called  development — is  proved  by  the  gradual  tapering  of  the  hair 
which  takes  place  after  the  point  has  been  removed:  of  the  truth  of 
this  fact,  not  the  slightest  doubt  can  be  entertained. 

At  the  period  of  puberty,  a  growth  of  hair  takes  place  in  certain 
situations  in  which  previously  it  was  not  apparent,  as  on  the  chin, 
cheeks,  in  the  axillae,  and  on  the  pubis,  abdomen,  and  chest;  this 
development  is  an  effect  of  the  great  functional  activity  which  exists 
at  that  period,  and  which  is  the  occasion  of  the  increased  and  rapid 
growth  of  the  several  constituents  of  the  body  which  then  takes  place. 

The  earliest  periods  at  which  the  rudiments  of  hairs  in  the  human 
fcetus  have  been  observed  is  from  the  third  to  the  fourth  month :  the 
hair  follicle  is  formed  in  the  first  place,  next  the  bulb,  and  then  the 
sheath  and  stem  of  the  hair,  which,  in  the  early  period  of  its  develop- 
ment, is  curved  upon  itself. 

Hairs  are  occasionally  developed  in  certain  peculiar  situations,  as 
on  the  mucous  membrane  of  the  conjunctiva,  the  intestines,  and  gall- 
bladder, in  the  ovaries,  and  in  steatomatous  and  encysted  tumours. 

Hairs  may  be  transplanted,  and,  it  is  said,  will  grow  after  such 
transplantation  in  consequence  of  the  adhesions  and  organic  connex- 
ion established  between  them  and  the  adjacent  tissues — a  fact  of 
which  practical  advantage  might  be  taken  if  correct. 

When  a  hair  has  obtained  the  full  term  of  its  development,  accord- 
ing to  the  researches  of  Eble,  it  becomes  contracted  just  above  the 
bulb :  this  change  probably  announces  its  death  and  approaching  fall. 

REGENERATION    OF    HAIRS. 

Hairs  are  peculiarly  susceptible  of  being  affected  by  the  condition 
of  the  health,  even  more  so  than  the  epidermis.    If  this  be  vigorous, 


HAIR.  299 

as  a  rule  to  which  there  are  many  exceptions,  it  will  be  found  that 
the  hairs  themselves  are  thick,  and  firmly  set  in  the  skin:  if,  on  the 
contrary,  the  powers  of  the  system  be  debilitated  from  any  cause,  the 
hairs  will  either  fall  off  spontaneously,  or  a  very  slight  degree  of  force 
will  serve  to  dislodge  them  from  their  connexions. 

If  the  bases  of  those  hairs  which  fall  out  of  themselves  be  examined, 
or  which  are  removed  by  combing  and  brushing,  it  will  be  seen  that 
the  bulb  alone  has  come  away,  the  entire  sheath  and  germ  remaining 
behind.  In  such  cases,  the  hair  is  doubtless  regenerated,  and  after 
its  regeneration,  is  usually  stronger  than  it  was  previously.  (See  Plate 
XXIX.) 

It  has  not  yet  been  ascertained  by  positive  experiment  whether  the 
hair  is  capable  of  reformation  in  those  instances  in  which  both  bulb 
and  sheath  have  been  removed:  it  is  most  probable,  however,  that 
where  they  have  been  entirely  abstracted,  no  renewal  of  the  hair 
could  ensue. 

It  is  possible  that  in  some  cases  the  apparent  regeneration  of  the 
hair  arises,  not  from  the  development  of  new  hairs  in  the  primitive 
sheaths  and  upon  the  old  germs,  but  from  the  formation  of  new  hair 
follicles  and  germs :  of  this,  however,  no  proof  has  as  yet  been  given. 

That  a  regeneration  of  new  shafts  of  hair  is  continually  in  progress, 
whether  from  new  germs  or  the  older  ones  is  not  known,  is  proved  by 
the  detection  of  small  and  pointed  hairs  just  emerging  from  the  skin 
in  the  scalp  of  even  old  persons. 

NUTRITION     OF    HAIR. 

Hairs  are  nourished  in  the  same  way  as  the  epidermis  itself;  that 
is,  they  do  not  receive  into  their  own  structure  either  blood-vessels  or 
nerves,  but  derive  their  nutriment  from  vessels  which  are  so  distrib- 
uted as  to  come  into  close  contact  with  the  tissues  to  be  nourished. 

This  indirect  reception  of  the  nutrient  plasma  explains  the  very 
great  susceptibility  of  the  epidermis  and  its  several  modifications  to 
be  influenced  by  causes  affecting  the  general  health,  and  in  conse- 
quence the  circulation  and  the  qualities  of  the  circulating  fluid. 

The  epidermic  tissues  being  placed  in  situations  the  most  remote 
from  the  centre  of  the  circulation,  are  endowed  with  but  a  feeble 
degree  of  vitality,  and  which  is  readily  destroyed  by  causes  affecting 
the  amount  and  nature  of  the  circulating  fluid  received  by  them. 

The  nutrient  vessels  and  sentient  nerves  of  each  hair  are  distributed 
around  and  outside  the  sheath,  and  not  in  a  raised  papilla,  as  generally 


300  THE     SOLIDS. 

described,  although  this  may  really  be  the  case  in  the  large  hairs  of 
the  whiskers  of  some  animals,  as,  for  example,  the  tactile  hairs  of  the 
seal,  &c.  The  fact  of  the  hair  usually  penetrating  below  the  level  of 
the  true  skin  and  into  the  sub-cutaneous  fatty  tissue  seems  to  dis- 
prove the  notion  of  a  distinct  and  vascular  papilla. 

DISTRIBUTION    OF    HAIRS. 

Hairs  are  distributed  over  the  entire  surface  of  the  body,  with  the 
exception  of  the  palms  of  the  hands,  soles  of  the  feet,  and  last  phalanx 
of  the  toes  and  fingers :  there  are,  however,  situations  in  which  they 
are  developed  in  increased  quantities,  as  on  the  integument  of  the 
scalp,  on  that  of  the  eyebrows,  on  the  margins  of  the  ciliary  cartil- 
ages, and  after  the  period  of  puberty,  on  the  chin,  cheeks,  axilla,  pubis, 
abdomen,  chest,  and  at  the  entrance  of  the  nares  and  ears. 

The  number  of  hairs  found  in  these  several  situations  differs  very 
considerably  in  different  individuals,  according  to  age  and  condition 
of  health. 

Individuals  of  the  male  sex  also  are  generally  more  hairy  than 
females,  in  whom  also  no  development  of  hairs  takes  place  on  the  chin, 
cheeks,  chest,  and  abdomen. 

Of  the  number  of  hairs  which  exist  on  the  entire  surface  of  the 
body,  some  idea  may  be  formed  from  the  measurements  of  Withof. 
The  quarter  of  a  square  inch  furnished  293  hairs  at  the  synciput,  at 
the  chin  39,  at  the  pubis  34,  on  the  fore-arm  23,  at  the  external  border 
of  the  back  of  the  hand  19,  and  on  the  anterior  surface  of  the  thigh 
13.  Upon  the  same  extent  of  surface,  Withof  counted  147  black 
hairs,  162  brown,  and  182  flaxen. 

Hairs  of  great  length  and  strength  are  often  developed  in  consider- 
able quantities  in  different  parts  of  the  body,  in  moles  and  naevi. 

DffiECTION    OF    HAIR. 

The  hair  follicles  are  not  placed  vertically  in  the  skin,  but  obliquely, 
and  the  hairs  which  issue  from  them  consequently  themselves  run  in 
the  same  oblique  direction.     (See  Plate  XXVI.  jig.  3.) 

The  apertures  of  most  of  the  follicles  look  downwards,  and  hence 
we  find  in  most  cases  that  the  points  of  the  hairs,  when  fully  devel- 
oped, are  similarly  directed. 

In  addition,  however,  to  this  general  arrangement  and  distribution, 
it  will  be  seen  that  in  early  life  the  hair  follicles  are  disposed  in  lines, 
the  apex  of  one  follicle  nearly  touching  the  base  of  the  next:  the  lines 


HAIR.  301 

thus  described  are  not  straight,  but  are  more  or  less  curved,  and 
divergent  or  convergent,  after  the  manner  of  the  lines  upon  the  case 
of  an  engine-turned  watch:  the  hairs  which  issue  from  the  follicles 
thus  take  particular  and  determinate  sweeps,  which  it  is  unnecessary 
to  describe  in  detail. 

It  occasionally  happens,  from  some  cause  or  other,  that  the  hair 
follicles  are  implanted  in  a  manner  the  reverse  of  that  which  should 
obtain:  this  is  especially  seen  in  those  of  the  scalp  of  children,  in 
whom  frequently  certain  tufts  of  hair  grow  up,  and  incline  in  a 
direction  opposed  to  that  of  the  contiguous  hair.  This  mal-disposition 
of  the  hair  is  the  source  of  much  trouble  and  annoyance  to  anxious 
nurses  and  mothers,  who  spend  much  time  in  endeavouring  to  bring 
the  refractory  lock  into  order. 

In  this  endeavour  there  can  be  no  question  but  that  it  is  possible  to 
succeed,  as  is  proved  by  the  very  different  arrangement  which  the 
hair  of  the  head  is  made  to  follow  in  accordance  with  the  manner  in 
which  it  is  dressed. 

ERECTION    OF    HAIR. 

Man,  to  a  certain  extent,  and  many  animals  in  a  considerable  degree, 
possess  the  power  of  erecting  the  hairs.  This  power  in  man  is  limited 
to  the  hairs  of  the  head,  in  many  animals  it  is  much  more  general. 

Most  persons,  on  sudden  exposure  to  cold,  and  on  experiencing  of 
any  emotion  of  fear  or  horror,  feel  a  creeping  sensation  pass  over  the 
head:  this  sensation  is  accompanied  by  a  certain  degree  of  erection 
of  the  hair,  but  not  indeed  to  such  an  extent  as  to  cause  it  "  to  stand 
on  end."  JMow,  this  erection  is  the  result  of  the  distribution  of  fibres 
of  elastic  and  contractile  tissue  throughout  the  substance  of  the 
corium,  and  which,  interlacing  among  the  hair  follicles,  occasion  the 
erection  of  the  hairs  themselves. 

The  distribution  of  these  fibres,  and  their  connexion  with  the  bases 
of  the  hairs,  are  well  seen  in  the  skin  of  the  hog. 

COLOUR    OF    HAIR. 

The  colour  of  the  hair  depends  upon  the  same  cause  as  that  of  the 
skin  and  eye,  and  is  due  to  the  presence  of  pigment  granules  and  cells ; 
these  are  contained  principally  in  the  medullary  canal,  but  are  also 
interspersed  between  the  fibres  of  the  stem ;  they  first  become  manifest 
in  the  upper  portion  of  the  bulb  of  the  hair. 

The  depth  of  the  colour  of  the  hair  very  generally  bears  a  relation 


302  THE     SOLIDS. 

to  the  development  of  pigmentary  matter  in  other  parts  of  the  system, 
as  in  the  eye  and  beneath  the  skin.  To  this  rule,  however,  some 
remarkable  exceptions  are  occasionally  encountered. 

The  colour  of  the  lighter  hairs,  as  the  red  and  flaxen,  would  appear 
to  depend  less  upon  the  number  and  depth  of  colouring  of  the  pigment 
cells  and  granules,  than  upon  the  presence  of  minute  globules  of  a 
coloured  oil. 

In  the  hair  of  Albinoes  but  little  colouring  matter  is  present;  and  in 
gray  hairs,  also,  the  colour  has  deserted  the  pigment  cells  and  granules. 

Hair  is  decolorized  by  long  contact  with  chlorine. 

It  is  generally  stated  as  an  undoubted  fact,  that  the  hair  may  turn 
white,  or  become  colourless,  under  the  influence  of  strong  and  depress- 
ing mental  emotions,  in  the  course  of  a  single  night.  This  singular 
change,  if  it  does  ever  occur  in  the  short  space  of  time  referred  to, 
can  only  be  the  result  of  the  transmission  of  a  fluid  possessing  strong 
bleaching  properties  along  the  entire  length  of  the  hair,  and  which  is 
secreted  in  certain  peculiar  states  of  the  mind. 

GRAY    HAIR. 

If  a  gray  hair  be  contrasted  with  an  unaltered  one  from  the  head 
of  the  same  person,  the  following  differences  will  be  noticed  between 
the  two.  The  gray  or  white  hair  will  be  observed  to  be  almost 
colourless,  the  bulb  and  fibrous  portion  will  be  destitute  of  colour,  the 
medulla  alone  retaining  a  slight  degree  of  coloration:  this,  however, 
is  collapsed,  and  in  place  of  being  continuous  throughout  its  length, 
will  be  seen  to  be  interrupted  at  intervals.    (See  Plate  XXVIII.  fig.  2.) 

The  unaltered  hair,  on  the  contrary,  is  distinguished  by  characters 
the  reverse  of  those  exhibited  by  the  gray  hair;  thus,  the  buib,  stem 
and  medulla  are  all  deeply  coloured,  and  the  latter  fills  the  entire 
cavitv  of  the  medullary  canal,  and  is  continuous  throughout.  (See 
Plate  XXVIII.  ^.1.) 

Gray  hair  retains  a  considerable  degree  of  vitality,  as  is  proved  by 
its  growth  continuing  for  many  years  after  its  loss  of  colour. 

PROPERTIES    OF    HAIR. 

Hairs  are  remarkable  for  their  strength,  their  elasticity,  durability, 
and  for  the  difficulty  with  which  they  undergo  the  process  of  decom- 
position: their  strength  results  probably  from  their  fibrous  constitution; 
in  their  elasticity  and  durability,  they  partake  of  the  character  of  all 
horny  structures. 


HAIR.  303 

The  strength  of  hair  is  proved  by  the  fact  that  a  single  hair  will 
bear  a  weight  of  1150  grains. 

Its  elasticity  is  shown  by  the  readiness  with  which  each  hair,  when 
extended,  returns  to  its  original  size  and  shape,  as  well  as  by  the  fact 
that  the  numerous  hairs  forming  a  curl  or  lock  will  recover  their 
ordinary  form  and  disposition  after  extension. 

Its  durability  is  shown  by  the  persistence  of  hairs  throughout  many 
years  of  life. 

Lastly,  its  indestructibility  is  proved  by  the  occurrence  of  hairs  in 
the  tombs  of  persons  buried  for  ages. 

A  hair,  however,  which  has  been  very  forcibly  extended,  will  not 
return  to  quite  its  original  length,  but  will  remain  a  certain  degree 
longer  than  it  was  previous  to  the  extension.  A  hair  may  be 
extended  a  third  of  its  length  without  breaking;  elongated  a  fifth,  it 
remains  a  seventeenth  longer  than  it  was  before ;  it  continues  a  tenth 
longer  after  having  been  extended  a  fourth,  and  a  sixth  only  after 
having  been  drawn  out  as  much  as  possible. 

Hairs,  when  they  are  dry,  become  electrical  by  rubbing,  and  emit 
sparks:  this  is  well  known  with  respect  to  the  coat  of  the  cat,  and 
Eble  has  observed  the  same  thing  to  occur  in  man. 

Hairs  are  also  eminently  hygroscopic,  and  imbibe  moisture  from 
the  air  and  from  the  skin,  in  consequence  of  which  they  lose  their 
set  or  curl,  and  become  flaccid  and  straight. 

Nitrate  of  silver  blackens  the  hair,  a  sulphuret  of  silver  being 
formed,  and  it  is  of  this  ingredient  that  the  majority  of  hair  dyes  are 
chiefly  constituted.  The  concentrated  mineral  acids,  especially  the 
nitric,  dissolve  the  hair,  as  does  also  caustic  potash. 

When  heated,  hairs  take  fire,  and  burn  with  a  fuliginous  flame, 
emitting  the  odour  of  bone,  and  leaving  a  residue  of  carbon.  To 
dry  distillation,  they  yield  a  quarter  of  their  weight  of  carbon,  which 
is  difficult  to  incinerate,  the  products  being  empyreumatic  oil,  water 
charged  with  ammonia,  and  combustible  gases,  which  comprise  sul- 
phureted  hydrogen.  The  ashes  contain  oxide  of  iron,  traces  of  oxide 
of  manganese  and  silica,  and  of  sulphate,  phosphate,  and  carbonate  of 
lime. 

THE    HAIRS    OF    DIFFERENT    ANIMALS. 

The  precise  structure  of  the  hairs  of  different  animals  varies  con- 
siderably :  those  of  the  mammalia  resemble  the  hairs  of  man,  or  differ 
only  in  the  degree  of  their  development,  as  the  whiskers  of  the 
carnivora  and  rodents,  and  manes  and  tails  of  horses,  the  bristles  of 


304  THE     SOLID. 

pigs,  &c. :  it  is  in  these  largely  developed  hairs  that  the  structure  can 
be  best  determined :  thus,  in  the  majority  of  them  it  is  stated  to  be 
easy  to  detect  the  vessels  and  nerves  of  the  papillae  on  which  the 
bulb  rests,  and  which  penetrate  into  it:  nerves  have  been  detected 
by  Eble  in  the  cat,*  by  Rapp  in  the  seal,  porcupine,  and  many  other 
animals,  f  and  by  Gerber  in  the  pig.  J 

In  the  hairs  of  the  musk-deer,  there  seems  to  be  no  separation 
of  parts  into  scaly  cortex,  fibres  and  medulla,  the  entire  hair  being 
uniformly  cellular. 

In  that  of  the  sable,  the  fibrous  portion  is  absent,  and  there  is  only 
scaly  cortex  and  cellular  medulla. 

In  the  hairs  of  most  rodents,  the  medulla  is  divided  by  dissepiments, 
and  in  other  animals,  as  the  sable,  it  is  composed  of  large  and  dis- 
tinct cells. 

The  hairs  of  the  mouse,  bat,  and  martin,  are  branched  or  knotted. 

In  the  spines  of  the  porcupine  and  hedge-hog,  the  inner  bark  pene- 
trates in  longitudinal  bands  into  the  cavity  of  the  medullary  canal, 
and  thus  divides  the  medulla  itself  into  incomplete  segments  ;  the 
transverse  view  of  such  spines  represent  a  starred  or  rayed  figure. 

In  birds,  hairs  are  replaced  by  feathers,  which  are  to  be  regarded 
as  modified  hairs. 

THE    USES    OF    HAIR. 

The  uses  of  hair  are  manifold. 

In  certain  situations,  as  on  the  head,  it  is  to  be  regarded  as  an 
ornament. 

In  other  localities,  as  on  the  cheeks  and  chin,  it  imparts  character 
and  expression  to  the  face. 

In  others  again,  as  on  the  pubis  and  about  the  genital  organs,  it 
serves  the  purpose  of  concealment. 

The  general  use  of  hair,  wherever  encountered,  it  being  a  non- 
conductor of  caloric,  is  to  preserve  the  warmth  of  the  system. 

Those  situated  at  the  entrance  of  the  nares  and  meatus  auditorius 
externus,  are  placed  there  to  prevent  the  entrance  of  foreign  bodies, 
insects,  &c. 

It  is  difficult  to  assign  any  use  to  the  hairs  of  the  axillae. 

It  is  very  probable  that  hairs  have  other  uses,  and  that  they  exert 
some  influence  in  regulating  the  electric  condition  of  the  body. 

*  Von  den  Haaren,  t.  11.  p.  19.       f  Verrichtangen  desfreuften  Nervenpaares,  p.  13. 
J  Allgemeine  Anatomie,  p.  79. 


HAIK.  305 

HAIR. 
[Plate  LXX.,  fig.  4,  represents  transverse  sections  of  the  human  hair. 

Transverse  sections  of  the  hair,  sufficiently  thin  to  show  the  cellular 
structure,  are  somewhat  difficult  to  make.  When  an  instrument  can  be 
obtained,  such  as  is  used  for  making  thin  sections  of  wood,  they  can  be 
prepared  by  taking  a  number  of  hairs,  and  gluing  them  together  by  means 
of  some  adhesive  material,  so  as  to  form  a  solid  mass.  This  bundle  is  then 
placed  in  the  machine,  properly  wedged,  and  the  transverse  sections  readily 
made. 

Another  method,  is  to  puncture  a  cork  with  a  fine  needle,  and  insert  or 
drive  hairs  in  it ;  when  a  sufficient  number  of  hairs  have  been  thus  intro- 
duced, thin  sections  of  the  cork  may  be  made  with  a  sharp  scalpel  or  razor. 
In  these  sections  will  be  found  some  of  the  hairs  cut  transversely,  and  suffi- 
ciently thin  to  show  their  structure. 

Sections  of  the  beard  may  be  obtained  by  repeating  the  operation  of 
shaving  a  couple  of  hours  after  the  beard  was  first  cut ;  on  the  razor  will  be 
found  minute  points  of  hair.  Some  of  these,  when  separated  and  spread  out 
with  the  needle,  will  exhibit  transverse,  others  longitudinal  sections. 

When  these  are  sufficiently  thin  to  show  their  structure,  they  should  be 
mounted  dry ;  but  if  too  thick  to  show  well  in  this  condition,  they  may  be 
rendered  more  transparent  by  being  mounted  in  balsam. 

The  hairs  of  different  animals  present  great  varieties  of  structure,  and 
their  study  will  be  found  replete  with  interest.] 

20 


306  THE     SOLIDS, 


ART.    XIV.  — CARTILAGES. 

Cartilages  are  among  the  most  solid  structures  entering  into  the 
constitution  of  the  animal  organization;  they  are,  however,  not  less 
remarkable  for  their  elasticity  and  flexibility  than  for  their  solidity. 

The  essential  element  of  the  several  fluids  and  solids  hitherto 
described  in  the  course  of  this  work,  we  have  seen  to  be  cells:  this 
cellular  composition  is  exhibited  in  a  high  degree  by  cartilages. 

The  texture  and  colour  of  the  cartilaginous  tissue  varies  consider- 
ably :  it  presents  either  a  white  or  bluish-white  semi-transparent  and 
homogeneous  appearance,  or  it  is  yellow,  and  exhibits  a  fibrous  texture. 

These  differences  of  texture  and  of  colour  indicate  a  difference  of 
structure,  upon  which  a  division  of  cartilages  into  the  true  and  fibro- 
cartilages  has  been  based. 

TRUE    CARTILAGES. 

True  cartilages  consist  of  cells,  contained  in  cavities,  which  are 
themselves  formed  in  a  solid  and  hyaline  inter-cellular  substance. 

They  comprise  all  those  cartilages  which  cover  the  articular  extre- 
mities of  the  bones  (that  of  the  glenoid  fossa  and  of  the  head  of  the 
inferior  maxilla  alone  excepted),  the  cartilages  of  the  entire  respiratory 
apparatus  (with  the  exception  of  the  epiglottis  and  the  cuneiform  car- 
tilages), those  cartilages  which  are  to  a  considerable  extent  free  and 
independent,  and  which  have  been  denominated  figured  cartilages,  as 
those  of  the  ribs,  the  ensiform  cartilage ;  the  trochlea  of  the  eye,  the 
nasal  cartilages,  and  the  Corpuscula  triticea  in  the  lateral  hyo-thyroid 
ligaments.     (See  Plate  XXX.  figs.  1  and  2.) 

The  true  cartilages  are  distinguished  from  the  fibro-cartilages  by 
their  bluish  and  transparent  aspect. 

Structure  of  True  Cartilages. 

True  cartilages  consist,  as  already  mentioned,  of  hyaline  matrix, 
cavities,  and  cells;  each  of  these  constituents  will  be  described  in 
succession. 

Hyaline  Matrix. — The  inter-cellular  substance,  or  hyaline  matrix, 
although  it  does  not  usually  present  any  distinct  traces  of  organization, 
yet  contains,  scattered  through  it,  numerous  granules  of  different  sizes, 
and  many  of  which  are  to  be  regarded  as  the  cytoblasts  from  which 
new  cells  are  continually  being  developed. 


CARTILAGES.  307 

The  amount  of  this  inter-cellular  substance  varies  in  different  car- 
tilages, and  is  greater  in  fully-developed  than  in  very  young  cartilage. 

Cavities. — The  cavities  of  true  cartilages  vary  both  in  size  and  form; 
in  shape  they  are  irregular,  although  for  the  most  part  elongated. 

They  are,  in  most  cases,  to  be  regarded  as  simple  excavations  or 
fossae  in  the  hyaline  matrix;  in  others,  however,  it  would  appear  from 
the  observations  of  Henle,*  Bruns,f  and  Schwann, J  that  they  are 
lined  by  a  distinct  membrane,  and  which  is  indicated  by  a  double 
contour,  by  the  difficulty  experienced  in  setting  free  the  contained 
cells,  and  by  the  fact  that,  by  boiling,  the  inter-cellular  substance  is 
dissolved,  while  the  cavities  remain  as  distinct  corpuscles. 

Such  cavities  would  stand  in  the  relation  of  parent  cells  to  those 
which  they  include. 

Cells. — The  cells  of  cartilages  are  very  different  from  those  occur- 
ring elsewhere  in  the  animal  organization;  they  are  distinct  in  their 
form  and  in  the  character  of  their  contents. 

Cartilage  cells,  like  the  cavities  in  which  they  are  enclosed,  are 
irregular  in  size  and  shape;  they  are,  however,  generally  elongated, 
sometimes  flattened  and  compressed;  at  others,  they  are  perfectly 
spherical :  these  several  shapes  depend  upon  the  degree  of  pressure  to 
which  the  cells  are  subject,  and  which  is  greatest  at  the  free  margins 
of  the  cartilages  where  the  compressed  form  occurs,  and  least  in  the 
centre  where  the  spherical  cells  are  chiefly  encountered.  Each  cell 
contains  a  nucleus,  which  is  either  smooth  or  granular;  it  includes 
also  very  generally  one  or  more  shining  and  globular  bodies  of  an 
oleaginous  or  fatty  nature,  and  which,  in  many  cases,  are  to  be 
regarded  as  transformed  nuclei. 

The  cells  usually  lie  as  it  were  scattered  irregularly  throughout  the 
inter-cellular  substance ;  in  some  cases,  however,  they  are  arranged  in 
definite  order;  thus,  in  the  condensed  margin  of  all  the  true  cartilages 
the  cells  are  compressed,  and  lie  with  their  long  axes  disposed  parallel 
to  the  surface.  (See  Plate  XXX.  fig.  1.)  Again,  in  the  ribs,  they 
radiate  in  straight  lines  from  the  centre  towards  the  circumference: 
this  disposition  of  them  accounts  for  the  fibrous  fracture  which  they 
exhibit  when  broken  across,  as  also  for  the  fact  of  their  being  divis- 
ible into  thin  transverse  layers.  The  linear  arrangement  of  the  cells 
in  the  fully-developed  cartilages  of  the  ribs  is  very  frequently  not 
perceptible. 

In  very  thin  cartilaginous  laminae,  as  those  forming  the  alae  of  the 
*  Anal.  Gen.,  vol.  vii.  p.  364.  -f  Allg.  Anat.,  p.  215.  \  Mikrosk.  Untersuch 


308  THE     SOLIDS. 

nose,  the  difference  in  the  form  of  the  central  and  peripheral  cells 
does  not  exist,  the  entire  inter-cellular  substance  being  filled  with 
small  and  rounded  cells. 

The  cells  usually  occur  singly  in  the  hyaline  matrix;  they  are, 
however,  frequently  encountered  in  groups  of  two,  three,  or  four  cells, 
each  of  which  is  distinct,  and  describes  a  more  or  less  regular  seg- 
ment of  a  circle:  this  disposition  of  the  cells  is  connected  with  their 
mode  of  multiplication,  as  will  be  seen  hereafter. 

Again,  groups  of  secondary  cells  sometimes  occur,  especially  in  the 
inter-vertebral  fibro-cartilages,  included  in  the  membrane  of  the  pri- 
mary or  parent  cell.     (See  Plate  XXXI.) 

Moreover,  Henle*  has  noticed  a  peculiar  arrangement  of  the  cells 
of  the  cartilages  which  cover  the  articulating  surfaces  of  the  larger 
bones.  On  the  free  surface,  the  cells  are  as  in  most  cartilages  small, 
flattened,  and  disposed  horizontally;  the  deeper  seated  cells  become 
larger  and  longer;  their  axes,  on  the  contrary,  being  directed  either 
vertically  or  obliquely  to  the  surface ;  sometimes  also  the  cells, 
although  separated  by  distinct  intervals,  are  arranged  the  one  above 
the  other  in  such  a  manner  as  that  the  superior  appears  to  be  a  con- 
tinuation of  the  inferior;  at  others,  an  inferior  cell  appears  to  divide 
into  two  others,  placed  above  it,  and  thus  represents  a  bifurcation. 
Henle  also  states,  that  he  has  seen  not  unfrequently  the  outline  of  a 
cavity  prolonged  from  one  longitudinal  series  of  cells  to  a  neighbour- 
ing series.  It  is  very  possible,  Henle  goes  on  to  observe,  that  these 
cavities  form  part  of  a  system  of  elongated  canals,  which,  taking  an 
undulous  course,  and  sometimes  bifurcating,  traverse  the  cartilage 
from  its  inferior  to  its  superior  surface,  and  which,  when  one  makes 
a  section,  are  divided  into  twro  portions,  the  one  remaining  in  one 
segment,  the  other  in  the  other  segment.  This  structure,  he  proceeds 
to  remark,  explains  sufficiently  why  articular  cartilages  exhibit  a 
fibrous  fracture,  and  why  the  earlier  observers  believed  them  to  be 
composed  of  fibres  which  ran  perpendicularly  to  the  thickness. 

This  ingenious  notion  of  Henle,  although  it  serves  to  account  for 
some  hitherto  unexplained  phenomena  connected  with  the  articular 
cartilages,  is  yet  of  very  doubtful  application  even  to  them,  and  cer- 
tainly no  such  arrangement  of  the  cells  and  cavities  as  that  just 
described  belongs  to  the  majority  of  true  cartilages,  or  to  any  of  the 
fibro-cartilages. 

NSar  the  surface,  the  articular  cartilages  are  more  laminated,  and 
may  be  separated  into  thin  lamellae. 

*  Anat.  Gen.,  vol.  vii.  p.  366. 


CARTILAGES.  309 

In  the  smaller  articular  cartilages,  the  number  of  cavities  and  cells 
is  more  considerable,  and  the  superficial  layer  of  cells  is  not  so  well 
marked:  the  peripheral  cells  are  small  indeed,  but  for  the  most  part 
rounded;  a  few  are  found  in  the  neighbourhood  of  the  bone,  of  an 
elliptical  figure,  but  the  middle  layer  presents  circular  cavities,  with 
cells  which  are  either  single  or  multiple. 

Nuclei. — The  nuclei  contained  in  cartilage  cells  are  mostly  granular, 
but  sometimes  present  a  smooth  aspect,  and  then  are  scarcely  to  be 
discriminated  from  particles  of  oil  or  fat:  in  form  they  are  sometimes 
rounded,  but  in  general  they  are  irregular  in  shape,  and  follow  more 
or  less  closely  the  contour  of  the  cells  in  which  they  are  enclosed; 
they  also  frequently  enclose  a  nucleolus. 

Usually  but  a  single  nucleus  is  contained  in  each  cell;  occasionally, 
however,  two,  three,  and  even  several  are  included  within  it;  and 
sometimes  it  happens  that  one  or  more  of  these  is  invested  by  a  dis- 
tinct cell-membrane.     (See  Plate  XXXI.) 

The  cells  also  include,  as  already  remarked,  particles  of  oil  of  a 
globular  form  and  of  a  shining  aspect;  it  has  been  suggested  that 
these  may  probably  in  some  cases  be  transformed  nuclei. 

The  distinction  of  cartilages  into  true  and  fibro-cartilages,  although 
useful  for  the  purposes  of  classification,  is  to  some  extent  artificial; 
since,  on  the  one  hand,  some  of  the  true  cartilages,  as  old  age 
approaches,  become  converted  into  fibro-cartilage,  and  on  the  other, 
the  fibro-cartilages  themselves,  in  the  early  period  of  their  develop- 
ment, do  not  contain  fibres,  the  cellular  substance  being  hyaline,  and 
identical  with  that  of  true  cartilages. 

The  conversion  of  hyaline  cartilage  into  fibro-cartilage  has  been 
observed  to  occur  only  in  those  cartilages  which  are  subject  to 
become  ossified,  as  those  of  the  ribs,  the  thyroid,  &c. 

Where  ligaments  are  inserted*  into  true  cartilaginous  tissue,  this  in 
the  neighbourhood  of  such  insertion  always  exhibits  a  fibrous  struc- 
ture, in  consequence  of  the  fibres  of  the  ligament  penetrating  into 
the  inter-cellular  substance.  These  fibres  are  of  a  nature  totally 
distinct  from  proper  cartilage  fibres,  as  will  be  seen  hereafter. 

FIBRO-CARTILAGES. 

Fibro-cartilages  differ  chiefly  from  true  or  hyaline  cartilages,  in 
that  the  homogeneous  inter-cellular  substance  is  replaced  in  them  by 
fibres  endowed  with  elasticity ;  a  transformation  of  structure  of 
which  we  have  seen  that  certain  of  the  true  cartilages  are  suscep- 
tible.    (See  Plate  XXXI.) 


310  THE     SOLIDS. 

The  fibro-cartilages  include  those  of  the  articulations  which  are 
united  by  synchondrosis,  as  the  intervertebral  cartilages,  and  that  of 
the  symphysis  pubis;  the  epiglottis  and  the  cuneiform  cartilages;  the 
articulating  cartilages  of  the  glenoid  cavity,  and  of  the  head  of  the 
superior  maxillary-bone;  the  inter-articular  cartilage  of  the  sterno- 
clavicular articulation;  the  cartilages  of  the  ear,  of  the  Eustachian 
tube,  of  Santorini,  and  those  of  Wrisberg. 

There  are,  however,  other  differences  besides  the  structural  one 
alluded  to;  thus,  fibro-cartilages  are  more  opaque  than  the  true,  are 
of  yellow  colour  more  or  less  deep,  and  are  endowed  with  a  higher 
degree  of  elasticity  and  flexibility. 

The  fibres  do  not  follow  the  same  distribution  in  every  fibro- 
cartilage :  thus,  in  the  tube  of  Eustachius,  in  the  symphysis  pubis,  in 
the  inter-articular  cartilage  of  the  sterno-clavicular  articulation,  in 
those  of  the  tempero-maxillary  articulation  they  are  placed  nearly 
parallel  to  each  other;  in  the  inter- vertebral  cartilages,  they  ascend 
vertically  from  one  osseous  surface  to  the  other;  in  the  cartilages  of 
the  epiglottis  and  ear,  they  are  curved  and  interlacing. 

In  the  outer  part  of  each  inter- vertebral  cartilage,  the  fibres  form  a 
distinct  and  compact  stratum  of  a  yellow  colour,  no  cartilage  cells  in 
that  situation  intervening  between  them;  the  number  of  fibres,  how- 
ever, gradually  diminishes  towards  the  centre  of  the  cartilage,  which 
at  the  same  time  becomes  less  and  less  dense  and  firm,  until  at  length 
in  the  very  axis  it  is  semi-fluid. 

The  cells  of  fibro-cartilages  do  not  differ  very  materially  in  form  and 
structure  from  those  of  true  cartilages ;  they  usually,  however,  contain 
more  fat,  are  more  readily  separable  from  the  fibrous  base  in  which  they 
are  lodged,  and  oftener  encountered  in  the  condition  of  parent  cells. 

The  cells  of  the  inter-vertebral  cartilages  and  of  the  epiglottis 
present  some  interesting  forms  and  modifications :  thus,  the  cells 
which  are  situated  in  the  harder  parts  of  those  cartilages  are,  on  a 
vertical  section,  seen  to  be  narrow  and  much  elongated;  while  many 
of  those  imbedded  in  their  soft  and  central  parts  are  large  and  per- 
fectly globular;  many  others  of  these,  again,  are  in  the  condition 
of  parent  cells,  and  enclose  either  numerous  nuclei  or  else  many 
perfectly-formed  secondary  cells ;  lastly,  cells  occasionally  present 
themselves  made  up  of  concentric  vesicles  enclosed  one  within  the 
other.  Groups  of  adherent  nuclei  are  also  frequently  met  with 
deprived  of  an  investing  membrane.  For  representations  of  these 
several  forms  of  cells,  see  the  figures. 


CARTILAGES.  311 

Henle*  describes  as  occurring  in  the  epiglottis  certain  large, 
spherical,  or  oval  cells,  presenting  in  their  interior  an  oblong  cavity, 
from  which  proceed  little  branched  tubes,  which  extend  in  all  direc- 
tions, even  to  the  surface  of  the  cells.  These  cells  would  appear  to  have 
some  analogy  with  the  osseous  corpuscles.  I  have  made  diligent  search 
for  them  in  the  epiglottis,  but  hitherto  have  failed  to  meet  with  them. 

The  fibro-cartilages  are  not  soluble  to  the  same  extent  in  boiling 
water  as  the  true,  which  are  almost  entirely  so,  and  therefore  yield 
less  chondrine  or  jelly.  The  cells  of  these  cartilages  also  resist  the 
action  of  the  water  for  a  longer  period  than  the  inter-cellular  sub- 
stance, f 

NUTRITION    OF    CARTILAGE. 

Cartilages  are  among  the  number  of  non-vascular  substances — that 
is,  they  do  not,  in  general,  receive  into  their  own  tissue  distinct 
blood-vessels,  but  derive  their  nourishment  from  those  which  are 
distributed  to  the  parts  adjacent  to  them. 

Thus,  the  articular  cartilages  are  supplied  with  nutriment  from  the 
vessels  which  are  so  freely  distributed  to  the  extremities  of  the  bones; 
in  young  children,  and  sometimes  even  in  adults,  the  synovial  mem- 
brane which  covers  the  free  surfaces  of  the  cartilages  also  carries 
vessels  which  assist  in  their  nourishment. 

The  independent  or  figured  cartilages,  as  the  ribs,  &c,  are  sur- 
rounded by  a  membrane,  composed  of  condensed  cellular  tissue, 
called  the  perichondrium :  in  this  membrane  the  vessels  which  afford 
nutriment  to  the  enclosed  cartilages  ramify.  The  ribs,  moreover, 
contain  grooves  or  canals,  which,  commencing  on  the  inner  edge 
of  the  rib,  first  run  towards  the  centre,  and  then  continue  to  pass 
forwards  for  some  distance :  these  canals  also  contain  blood-vessels. 

In  the  centre  of  ribs  about  to  ossify,  a  distinct  medullary  canal, 
containing  blood-vessels  in  abundance,  is  clearly  perceptible. 

Vessels  are  also  contained  in  the  fatty  masses  enclosed  in  some 
of  the  joints,  and  called  the  glands  of  Havers ;  from  these  the 
adjacent  cartilages  doubtless  imbibe  a  portion  of  nutrient  plasma. 

Among  fibro-cartilages,  the  synchondroses  are  stated  to  receive 
vessels.  Nerves  have  not,  as  yet,  been  discovered  in  cartilages, 
which  may  be  irritated  for  any  length  of  time  without  the  slightest 
pain  being  occasioned. 

*  Anal.  Gtn.,  vol.  vii.  p.  370. 

f  Meckauer  (Carlilag.  Slructura,  1836,)  appears  to  have  been  the  first  to  give, 
under  the  direction  of  Purkinje,  a  complete  and  accurate  description  of  the  cartilages 
of  the  human  body. 


312  THE     SOLIDS. 

During  ossification,  between  the  cartilage  to  be  converted  into 
bone  and  that  which  is  to  remain  as  the  articular  cartilage,  a  layer 
of  vessels  passes,  which,  as  the  ossification  advances,  gradually  retire, 
and  wholly  disappear  soon  after  birth. 

As  cartilages  do  not  contain  vessels,  they  are  not  subject  to  those 
disorders  which  depend  upon  errors  of  the  circulation;  that  is,  they 
are  not  liable  to  inflammation  and  its  consequences.  Ulceration 
of  cartilages  is  indeed  described  by  writers ;  but  this  term  is  wanting 
in  accuracy  when  applied  to  the  erosion  of  which  cartilages  are 
susceptible,  and  which  is  effected  not  through  any  operation  occur- 
ring in  the  cartilage  itself,  but  through  the  action  of  vessels  which, 
proceeding  from  the  synovial  membrane,  dip  down  into  the  cartilage, 
and  occasion  its  partial  absorption.  For  the  same  reason,  cartilages 
do  not  readily  become  atrophied  by  pressure :  thus,  when  an  aneurism 
destroys  the  bodies  of  the  vertebrae,  the  inter-vertebral  cartilages  are 
not  at  the  same  time  removed,  but  resist  for  a  long  period  the  con- 
tinued compression  to  which  they  are  subject. 

There  is,  however,  one  description  of  cartilage  in  which  blood- 
vessels regularly  appear,  viz:  cartilages  of  ossification,  in  which  may 
be  included  the  costal  and' thyroid  cartilages,  their  presence  proceed- 
ing and  accompanying  the  process  of  the  formation  of  bone. 

Cartilages,  like  all  the  extravascular  tissues,  imbibe  fluid  readily: 
thus,  when  immersed  in  a  coloured  solution,  they  assume  the  tint  of 
the  liquid  in  which  they  are  placed.  In  jaundice,  according  to 
Bichat,*  they  present  a  greenish  yellow  tint,  from  the  imbibition  of  a 
portion  of  the  bile  with  which,  in  this  disorder,  the  system  is  so 
pregnant. 

GROWTH    AND    DEVELOPMENT    OF    CARTILAGES. 

Cartilages,  as  already  observed,  consist  of  cells  imbedded  in  a  hyaline 
or  fibrous  base.  In  considering,  then,  the  development  of  cartilages, 
the  growth  of  both  the  cells  and  the  inter-cellular  substance  must  be 
discussed. 

We  will  first  describe  the  multiplication  of  cartilage  cells. 

The  Cells. — Cartilage  cells  are  multiplied  in  two  ways. 

1st.  By  the  division  of  a  single  cell  into  two  or  more  parts,  each  of 

which  becomes,  when  the  separation  is  completely  effected,  a  distinct 

cell.     The  reality  of  this  method  of  increase  in  the  number  of  cells 

will  become  evident,  on  the  attentive  examination  of  almost  any  thin 

*Anal.  Gen.,t.  iii.  p.  192. 


CARTILAGES.  313 

section  of  cartilage,  in  the  cells  of  which,  but  especially  in  those  placed 
near  the  natural  border,  the  several  stages  of  their  division  may  be 
clearly  and  satisfactorily  recognised.     (See  Plate  XXX.) 

2d.  By  the  development  of  cytoblasts  either  in  the  inter-cellular 
substance,  or  else  in  parent  cells.  This  mode  of  increase  is  a  true 
reproduction,  new  cells  being  continually  formed  and  developed. 
The  first  process  of  multiplication  is  of  a  nature  totally  distinct  from 
reproduction ;  for  although  by  it  the  cells  are  multiplied,  no  new  ones 
are  developed.  There  is  the  same  difference  between  the  two  forms 
of  cells,  that  having  its  origin  in  the  division  of  a  single  cell,  and  that 
developed  from  a  cytoblast,  as  there  is  between  a  slip  and  a  seed. 
(See  Plates  XXX.  and  XXXI.) 

The  parent  or  primary  cells,  filled  with  the  second  or  even  the 
third  generation  of  new  cells,  may  be  detected  in  abundance  in  almost 
any  cartilage,  but  especially  in  the  inter-vertebral  cartilages.  It  is 
worthy  of  notice,  that  the  parent  cells  are  usually  situated  near  the 
centre  of  each  cartilage,  while  the  single  cells,  in  which  the  process 
of  division  is  best  seen,  are  mostly  found  outside  these.  From  this 
arrangement  we  may  infer  that  the  deeper-seated  cells  are  older  than 
those  of  the  circumference.  Whether  the  latter  are  derived  from  the 
former,  or  whether  they  are  formed  on  the  external  margin  of  the 
cartilage,  it  is  not  easy  to  decide ;  it  is  most  probable,  however,  that, 
from  the  circumstance  that  the  parent  cells  are  principally  found  in 
the  centre  of  the  thicker  cartilages,  and  that  it  is  in  this  situation  that 
ossification  commences,  that  the  second  conjecture  is  the  correct  one. 

It  is  a  singular  fact,  that  the  development  of  cartilage  cells  may  be 
as  readily  followed  out  in  old  cartilages  as  in  young,  numbers  of  cells 
in  process  of  division  and  in  the  stage  of  parent  cells  being  readily 
distinguished  in  each.  As  after  maturity  cartilages  do  not  undergo 
any  increase  in  size,  and  as  from  the  preceding  observations  it  would 
appear  that  new  cells  are  continually  being  evolved,  it  must  be  pre- 
sumed that  the  very  old  cells  are  absorbed  and  their  place  supplied 
by  the  younger  ones. 

In  the  multiplication  of  cartilage  cells  by  division,  a  correspondence 
may  be  traced  between  cartilages  and  many  of  the  lower  tribes  of 
animals  and  vegetables,  especially  with  the  majority  of  the  algae ;  and 
in  the  development  of  secondary  cells  in  parent  cells,  they  exhibit  a 
still  closer  analogy  with  certain  algae  of  the  genera  Hcematococcus  and 
Mycrocyslis,  the  cells  of  some  of  the  species  of  which  it  would  be 
impossible  to  distinguish  from  the  isolated  cartilage  corpuscles  of  the 
epiglottis  and  inter-vertebral  cartilages. 


314  THE     SOLIDS. 

In  these  methods  of  multiplication,  cartilage  cells  would  appear 
almost  to  stand  alone  in  the  animal  economy:  thus,  it  is  certain  that 
the  red  blood  corpuscles,  epithelial  cells,  and  their  various  modifica- 
tions into  epidermis,  nails,  pigment  cells,  and  hairs,  are  not  multiplied 
either  by  division  or  by  the  development  of  secondary,  enclosed  in 
primary  or  parent  cells. 

The  analogy  existing  between  the  cells  of  cartilages  and  those  of 
certain  algas  has  been  noticed  by  Dr.  Carpenter,  in  the  third  edition 
of  his  "Principles  of  Human  Physiology." 

The  Inter -cellular  Substance. — Very  young  cartilages,  and  also  the 
smaller  ones  of  adults,  are  constituted  almost  entirely  of  cells,  with  but 
little  admixture  of  inter-cellular  substance.  As,  however,  these  young 
cartilages  grow  in  size,  the  relative  amount  of  this  substance  increases, 
and  the  space  between  the  cells  becomes  greater. 

The  augmentation  of  the  inter-cellular  substance  takes  place  prin- 
cipally by  a  deposit  of  new  layers  on  the  exterior  surface  during  the 
period  of  the  development  of  cartilages;  this  mode  of  increase  is 
proved  by  their  separation  after  long-continued  maceration  into  dis- 
tinct laminae. 

A  second  mode  of  increase  of  the  inter-cellular  substance  has  been 
stated  to  exist  by  Henle,*  principally  in  the  cartilages  of  ossification, 
and  under  no  circumstances  in  the  fibro- cartilages,  viz :  by  the  thick- 
ening of  the  walls  of  the  cells,  which  become  confounded  with  or 
melted  down  into  the  inter-cellular  substance,  the  cavity  in  which  the 
cells  are  lodged  being  diminished,  or  this  also  augmenting  at  the  same 
time.  The  proofs  adduced  in  favour  of  this  method  of  increase  are 
not  convincing. 

It  has  already  been  stated  that  in  the  true  cartilages  which  are 
subject  to  ossification,  fibres  appear;  these  fibres,  as  well  as  the  anal- 
ogous ones  of  fibro-cartilages,  are  probably  of  a  nature  wholly  distinct 
from  those  of  ordinary  cellular  tissue,  and  which  have  their  origin  in 
cells ;  under  no  circumstance  can  either  cells  or  nuclei  be  discovered 
in  the  fibres  of  cartilages. 

Cartilage  is  not  capable  of  regeneration:  when  it  has  been  frac- 
tured, the  union  of  the  surfaces  is  very  incomplete,  and  principally  by 
means  of  cellular  tissue. 

The  formation  of  cartilage  almost  invariably  precedes  the  develop- 
ment of  bone,  of  which  we  shall  shortly  have  to  speak  more  particu- 
larly in  the  Chapter  on  Bone. 

*  Anat.  Gen.,  vol.  vii.  p.  376. 


CARTILAGES.  315 

Masses  of  cartilage  are  also  occasionally  produced  upon  the  exter- 
nal surface  of  the  synovial  membrane  of  joints;  these  are  at  first 
peduncated,  but  at  length  cease  to  have  any  connexion  with  the  organ- 
ization, and  move  freely  about  in  the  cavity  of  the  joints. 

Occasionally,  though  rarely,  cartilage  is  developed  in  the  cellular 
tissue  of  glands,  forming  a  solid  tumour,  which  was  first  described  by 
Muller,  under  the  name  of  Enchondro?nab  and  of  which  I  recently  had 
the  pleasure  of  receiving  a  very  excellent  example  from  Dr.  Letheby. 

USES    OF    CARTILAGES. 

The  uses  of  cartilages  are  of  a  mechanical  nature,  depending  upon 
certain  physical  properties. 

Thus,  we  find  them  to  be  situated  in  localities  where  solidity  is 
required  in  combination  with  flexibility  and  elasticity. 

In  the  larynx,  the  flexibility  and  elasticity  of  cartilages  assists  in  the 
modulation  of  the  voice. 

In  the  nose,  so  liable  to  injury,  their  flexibility  often  allows  this 
organ  to  sustain  severe  blows  without  detriment. 

The  articular  cartilages  protect  the  bones  from  injury  to  which  they 
would  be  otherwise  so  subject  in  the  sudden  and  violent  exertions  of 
the  body,  as  in  jumping,  on  account  of  their  solid  and  unyielding  nature. 

The  inter-vertebral  cartilages  are  exceedingly  elastic  and  flexible, 
and  permit  the  free  movement  of  the  spinal  column  in  almost  any 
direction,  and  which  is  so  necessary  in  the  execution  of  the  various 
motions  of  the  body. 

The  articulations  united  by  synchondrosis,  as  that  of  the  pubis, 
are  remarkable  for  their  strength,  although  at  the  same  time  it  admits 
a  slight  degree  of  extension  and  compression. 

Lastly,  the  epiglottis  is  enabled  to  preserve  the  erect  position  so 
essential  to  the  maintenance  of  life  in  consequence  of  its  exceeding 
elasticity. 


316  THE     SOLIDS. 

CARTILAGE. 

[For  an  elaborate  and  complete  account  of  "the  intimate  structure  of 
articular  cartilage,"  see  a  paper  on  that  subject,  with  plates,  by  Jos.  Leidy, 
M.  D.,  of  Philadelphia,  published  in  vol.  xvii.  (new  series)  of  the  American 
Journal  of  Medical  Sciences,  pp.  277-294. 

The  development  of  cartilage  is  of  course  best  studied  in  the  fetal  subject. 

In  the  adult,  cartilage  may  be  examined  in  their  vertical  sections. 
Articular  cartilage  is  easily  separated  from  bone,  after  slight  immersion  in 
acid. 

Preparations  of  cartilage  should  be  preserved  in  cells  with  fluid. 

Plate  LXX.,  fig.  5,  Cartilage  from  the  finger-joint,  showing  terminal  loop- 
ings  of  vessels.] 


BONE.  317 


ART.   XV.— BONE, 


The  next  tissue  to  be  considered  is  the  osseous. 

Bones  are  divided  after  their  form  into  long,  flat,  and  irregular: 
long  bones  consist  of  a  body  or  shaft  termed  diaphysis,  hollowed  out 
in  the  centre  into  the  medullary  canal,  and  of  two  extremities  called 
Epiphyses,  and  which  in  early  life  are  distinct  from  the  shaft;  each 
long  bone,  moreover,  is  made  up  of  two  modifications  of  bony  struc- 
ture, the  cancellous  and  the  tabular;  the  former  is  loose  and  reticular, 
the  latter  hard  and  compact:  of  the  one,  the  great  bulk  of  the 
epiphyses  are  constituted;  of  the  other,  the  diaphysis  is  chiefly  formed: 
in  flat  and  irregular  bones,  the  medullary  canal  is  wanting ;  the  first 
consist  of  an  inner  and  outer  table  of  compact  bony  tissue,  enclosing 
a  thin  plate  of  cancellous  structure,  termed  Diploce,  and  the  latter 
are  composed  principally  of  cancelli,  enclosed  in  thin  and  irregular 
osseous  laminae. 

STRUCTURE    OF    BONES. 

The  two  elements  into  which  all  bones  resolve  themselves  are 
osseous  corpuscles  and  laminae ;  the  latter,  according  to  the  plan  of 
their  arrangement  and  development,  give  rise  to  the  cancelli,  medul- 
lary canals,  and  plates  of  which  bones  are  constituted. 

Cancellous  Structure. 

The  cancellous  structure  of  bone  is  made  up  of  thin  and  inoscu- 
lating plates  of  bony  matter,  which  enclose  spaces  between  them,  and 
all  of  which  freely  communicate  with  each  other  :  these  spaces  are 
called  medullary  cells.  Each  plate  is  also  compounded  of  several 
laminae,  in  the  intervals  between  which  a  few  bone  corpuscles  exist. 

The  fact  of  the  free  communication  of  the  medullary  cells  is  proved 
by  the  two  following  experiments  : 

Thus,  when  mercury  is  poured  into  a  hole  made  in  the  exremity  of 
a  long  bone,  or  on  the  surface  of  a  flat  or  short  one,  it  will  traverse 
all  the  medullary  cells,  and  escape  by  the  apertures  which  exist 
naturally  on  the  exterior  of  bones. 

Again,  if  a  bone  be  cut  through  at  one  of  its  extremities,  the 
natural  openings  on  its  surface  being  at  the  same  time  closed,  and  if 


318  THE     SOLIDS. 

then  the  bone  be  exposed  to  the  action  of  heat,  all  the  marrow  will 
escape  slowly  by  the  cut  extremity.* 

The  spaces  described  by  the  medullary  cells  are  irregular  in  size 
and  form,  those  which  are  first  developed  being  smaller  than  those  of 
older  formation  (see  Plate  XXXIV.  fig.  3,  4) :  they  are  usually  of 
an  elongated  shape,  their  long  axes  being  parallel  to  that  of  the  bone 
itself:  when  viewed  transversely,  they  are  seen  to  be  more  or  less 
rounded,  but  irregular  in  outline :  it  is  in  the  transverse  sections  that 
the  bone  cells  and  lamellae  are  best  seen. 

Medullary  cells  in  the  recent  state  are  filled  with  fat  vesicles,  with 
blood-vessels,  and  with  granular  nucleated  cells  analogous  to  those  of 
epithelium:  these  last  occur  in  considerable  quantities  in  the  cancelli, 
and  especially  in  those  of  fetal  bones,  in  which  the  fat  vesicles  are 
for  the  most  part  absent.     (See  Plate  XXX.  fig.  4.) 

They  inosculate  freely  with  the  medullary  canals  situated  in  the 
outer  and  compact  plates  of  bone. 

Canalicular  Structure. 

The  compact  tissue  of  bones  is  traversed  by  canals,  which  have 
been  termed  medullary  from  the  fact  of  their  being  in  communication 
in  the  long  bones  with  the  great  central  medullary  cavity,  and  from 
the  circumstance  of  their  being  partly  occupied  with  medullary 
matter.     They  are  also  called  Haversian,  after  their  discoverer. 

These  canals  are  situated  between  the  laminae  of  which  bone  is 
composed,  and  take  a  course  in  the  long  bones,  in  which  they  are 
best  seen,  parallel  to  their  axes,  being  also  joined  together  by  short 
transverse  branches :  they  thus  form  a  net- work  of  tubes  analogous 
to  that  exhibited  by  the  minute  vessels  which  they  convey  and  pro- 
tect; the  form  and  sizes  of  the  meshes  vary:  in  the  long  bones  they 
are  elongated.     (See  Plate  XXXII.  fig.  4.) 

They  communicate,  in  the  long  bones,  with  the  medullary  cavity, 
dilating  into  cells  or  vesicles,  from  which  a  short  tube  proceeds 
previous  to  their  entrance  into  it;  they  also  open  upon  the  external 
surface  of  all  bones  by  somewhat  expanded  apertures,  and  inosculate 
freely  with  the  medullary  cells. 

Medullary  canals  are  not  all  of  equal  diameter  throughout  the 
compact  tissue  of  a  bone ;  those  situated  between  the  external  plates 
are  two  or  three  times  smaller  than  those  which  are  placed  more 
internally.     (See  Plate  XXXII.  fig.  1.) 

*Bichat,  Anatomie  Generate,  t.  111.  p.  25. 


BONE.  319 

In  a  transverse  section,  the  canals  are  seen  to  be  either  circular, 
oval,  or  rarely  angular. 

In  the  flat  bones,  the  comse  of  the  medullary  canals  is  more  irreg- 
ular than  in  the  long  bones;  in  the  parietal  bones  they  proceed 
diverging  from  the  parietal  protuberance  towards  the  margins  of  the 
bone;  and  in  the  frontal  from  the  supra  orbitar  ridge  towards  the 
coronal  suture. 

In  the  long  bones,  near  their  extremities  and  in  the  vicinity  of  the 
articular  cartilage,  these  canals  end  in  blind  or  csecal  extremities,  a 
single  canal  passing  up  into  each  of  the  prominences,  into  a  number 
of  which  the  articular  surface  of  bone  is  elevated.* 

It  is  these  canals,  which  impart  the  striated  structure  presented  by 
bone,  and  which  is  visible  to  the  unassisted  eye;  in  longitudinal 
sections,  they  are  frequently  cut  through,  and  their  cavities  exposed. 

The  contents  of  medullary  canals  are  similar  to  those  of  the  medul- 
lary cells,  of  which  they  are  to  be  regarded  as  a  modification,  there 
being  an  insensible  transition  from  the  one  to  the  other. 

Drs.  Todd  and  Bowman  recognise  two  forms  of  Haversian  canals, 
one  of  which  carries  veins,  the  other  arteries,  a  single  vessel  being 
distributed  to  each ;  those  canals  which  contain  the  veins  are  stated 
to  be  larger  than  those  which  convey  the  arteries,  and  to  be  dilated 
into  a  pouch  or  sinus  at  the  situation  where  two  or  more  canals  unite 
to  form  a  single  larger  tube. 

Lame  lice. 

The  more  essential  constituents  of  true  and  fully  developed  bone 
are,  as  already  observed,  lamellae  and  bone  cells;  the  medullary  cells 
and  canals  just  described  are  merely  definite  spaces  existing  between 
the  lamellae,  the  arrangement  and  ultimate  structure  of  which  we  shall 
in  the  next  place  proceed  to  notice. 

It  is  principally  by  the  successive  development  of  new  lamellae  that 
bones  increase  in  diameter;  these  are  usually  deposited  in  the  direc- 
tion of  the  axis  of  the  bone;  if,  therefore,  a  transverse  section  of  a 
long  bone  be  made  and  examined  with  the  microscope,  the  lamellae 
will  be  seen  to  be  arranged  as  follows:  First,  several  layers  will  be 
observed  to  pass  entirely  round  the  bone ;  secondly,  others  will  be 
noticed  encircling  each  Haversian  canal;  and  lastly,  irregular  and 
incomplete  lamellae  occupy  the  angular  spaces  intervening  between 

*  See  Med.  Chir.  Rev.  No.  x.  p.  528. 


320  THE     SOLIDS. 

the  sets  of  lamellae  concentrically  disposed  around  each  canal.  (See 
Plate  XXXII.  figs.  1,  2,  3.) 

The  number  of  layers  which  pass  interruptedly  around  the  bone 
are  not  very  numerous,  being  generally  less  than  twelve;  the  amount 
of  those  which  encircle  each  Haversian  canal  varies  from  two  or 
three  to  upwards  of  twelve,  the  smallest  number  of  lamellae  usually 
appertaining  to  the  smallest  canal.     (See  Plate  XXXII.  fig.  1.) 

Examined  with  an  object-glass  of  the  fourth  of  an  inch  focus,  the 
lamella,  after  the  separation  of  its  earthy  matter  by  means  of  dilute 
hydrochloric  acid,  exhibits  a  delicate  structure,  the  precise  nature  of 
which  it  is  not  easy  to  determine ;  its  surface  will  be  seen  to  be  marked 
out  into  innumerable  lozenge-shaped  spaces,  one  side  of  each  of  which 
is  concealed  by  a  dark  shadow,  and  the  divisions  between  which  are 
without  shadow.     (See  Plate  XXXIII.  fig.  4.) 

This  interesting  structure  was  first  distinctly  pointed  out  by  Dr. 
Sharpey,*  who  conceives  that  it  arises  from  the  crossing  and  union 
of  fibres;  these,  however,  cannot  be  traced  out  and  displayed  as  sepa- 
rate fibres,  owing,  it  is  presumed,  to  their  being  united  or  fused 
together  at  the  points  where  they  cross  each  other;  it  sometimes  hap- 
pens, however,  that  at  the  torn  edge  of  a  lamella  a  short  projecting 
process  may  be  seen,  which  presents  much  the  aspect  of  a  true  fibre.f 

The  appearance  presented  by  a  lamella  thus  figured  might  be  com- 
pared to  the  engine-turned  case  of  a  watch,  and  it  might  also  be  con- 
ceived that  it  was  produced  by  the  union  of  a  number  of  diamond- 
shaped  cells,  and  not  by  the  crossing  of  fibres. 

One  argument  in  favour  of  the  fibrous  constitution  of  the  lamellae 

O 

may  be  derived  from  the  fact  that  the  cancelli  of  bone  in  process  of 
development  clearly  exhibit  a  fibrous  structure. 

Cross  sections  of  the  lamellae  may  also  sometimes  be  observed  to  be 
marked  with  short  and  radiating  lines,  which  most  probably  depend 
upon  the  structure  already  noticed. 

The  osseous  lamellae  are  likewise  perforated  necessarily  with 
numerous  minute  apertures  occasioned  by  the  canaliculi  of  the  bone 
cells,  and  which,  when  seen  with  a  low  power,  appear  like  so  many 

*  Quain's  Anatomy,  5th  edition,  part  ii.  p.  cxlii. 

f  It  would  appear  to  he  prohahle,  from  the  following  quotation,  that  Henle  had 
seen  the  structure  ahove  described.  "  The  lamellae  examined  on  their  flat  side  have 
appeared  to  me  to  he  generally  hyaline  or  finely  dotted,  but  sometimes  also  fibrous  ; 
the  fibres  are  either  pale,  and  as  thougli  composed  of  grains,  or  obscure  and  rugged; 
one  never  succeeds  in  isolating  them  for  a  certain  space,  because  they  are  branched, 
interwoven,  and,  in  a  word,  perfectly  identical  with  the  fibres  of  fibro-cartilages." 


BONE.  321 

small  dots ;  they  contain,  also,  scattered  throughout  their  substance, 
multitudes  of  granules  of  earthy  matter. 

The  only  really  necessary  constituents  of  bone  would  appear  to  be 
the  cellular  tissue  and  earthy  matter.  The  combination  of  these  two 
forms  bone  in  its  simplest  condition.  The  medullary  cells,  Haversian 
canals,  and  bone  cells,  are  connected  only  with  the  growth  and  nutri- 
tion of  bone,  and  occur  seldom,  except  where  the  size  of  the  bony 
formation  renders  their  presence  necessary  for  its  growth  and  support. 

Bone  Cells. 

Distributed  throughout  the  cancellous  and  compact  portions  of  bone, 
cells  of  a  peculiar  structure  occur  in  considerable  quantities. 

Concerning  the  nature  of  these  cells,  much  difference  of  opinion 
prevails;  by  some  they  are  described  as  mere  vacuities  existing  in 
the  tissue  of  the  bone;  by  others  as  hollow  cells,  as  nuclei  of  cells, 
and  as  true  nucleated  corpuscles.  That  the  bone  cells  take  then- 
origin  in  nucleated  cells,  cannot  be  doubted. 

The  circumstances  which  have  given  rise  to  the  notion  of  their 
being  mere  vacancies  or  lacunae,  are  the  passage  of  fluids  through 
them,  their  infiltration  with  solid  matter,  and  the  optical  appearances 
sometimes  presented  by  them.  All  these  circumstances  admit,  how- 
ever, of  explanation  on  the  supposition  of  their  corpuscular  origin. 

That  they  are  derived  from  granular  cells  may  be  proved,  it  seems 
to  me,  by  the  study  of  the  development  of  bone,  they  being  in  growing 
bones  first  traceable  as  nucleated  corpuscles,  a  condition  to  which 
they  may  be  again  reduced  in  an  adult  bone  by  the  removal  of  the 
earthy  matter.  This  appearance  is  best  seen  in  the  large  bone  cells 
of  the  Siren,  Proteus,  or  Menobranchus. 

The  bone  cells,  which  are  very  numerous,  are  situated  between  the 
osseous  laminae  already  described,  and  by  which  they  are  compressed; 
they  thus  present  in  all  sections  of  bone  an  elongated  or  flattened  form, 
and  in  transverse  cuttings  those  facing  the  Haversian  canals  appear 
not  merely  elongated,  but  also  slightly  curved,  the  concavity  of  the 
arc  being  directed  inwards  towards  the  canals,  and  the  convexity  out- 
wards in  the  contrary  direction.     (See  Plate  XXXII.  Jigs.  1,  2.) 

When  viewed  as  transparent  objects,  they  appear  black,  and  when 
as  opaque,  they  are  of  a  pearly  whiteness. 

From  the  margins  of  each  bone  cell  proceed  a  number  of  branched 
canals,  which,  passing  through  the  lamellae  situated  on  either  side  of 
the  cell,  inosculate  freely  with  the  canaliculi  given  off  by  the  bone 

21 


322  THE     SOLIDS. 

cells  of  the  contiguous  lamellae  (see  Plate  XXXII.  fig.  3) ;  this  pro- 
cess of  inosculation  being  frequently  repeated  between  the  cells  of 
each  lamella,  a  communication  is  thus  established  between  the  me- 
dullary cavity  on  which  the  canaliculi  of  the  first  series  of  cells 
opens,  the  Haversian  canals,  and  the  external  surface  of  the  bone. 
The  reality  of  this  communication  may  be  attested,  by  applying  a 
drop  of  oil  of  turpentine  to  a  section  of  dry  bone  placed  beneath  the 
microscope,  when  the  passage  of  the  fluid  through  the  bone  cells  may 
be  followed  with  the  eye.  This  experiment  was  first  suggested  by 
Drs.  Todd  and  Bowman. 

The  canaliculi  of  bone  cells  treated  with  acid  usually  disappear,  the 
body  of  the  cell  alone  remaining. 

The  size  of  the  bone  cell  throughout  the  whole  of  that  osseous  ver 
tebrate  series,  stands  in  relation  to  that  of  the  red  blood  disc ;  and  Mr. 
Quekett,  who  has  instituted  an  inquiry  into  their  form  and  size  in  a 
great  variety  of  animals,  has  arrived  at  the  conclusion  that  the  class 
to  which  any  animal  belongs,  whether  that  of  Beasts,  Birds,  Reptiles, 
or  Fishes,  may  be  determined  by  the  two  particulars  referred  to. 
This  discovery  is  likely  to  be  especially  useful  in  the  determination  of 
the  true  position  in  the' animal  series  of  many  fossil  bones,  which  but 
for  it,  would  have  continued  to  be  enveloped  in  uncertainty  and 
conjecture. 

In  many  osseous  fishes,  the  bone  cells  appear  to  be  wanting,  they 
having  merged  into  canaliculi,  which  are  often  of  considerable  size. 

Marrow  of  Bones. 

The  medullary  cavity  of  adult  long  bones,  the  medullary  cells,  and 
the  larger  medullary  canals,  all  contain  a  loose  cellular  tissue,  in  the 
meshes  of  which  a  greater  or  less  amount  of  marrow  or  fat  cells  is 
enclosed.     (See  Plate  XXX.  figs.  3,  4.) 

In  foetal  and  very  young  bones  the  fat  vesicles  are  wanting  in  the 
three  situations  named,  the  place  of  fat  being  supplied  by  immense 
numbers  of  the  small  granular  nucleated  cells,  which  have  already 
been  referred  to.     (See  Plate  XXXIII.  fig.  5.) 

It  has  been  stated  that  the  medullary  cavity,  cells,  and  canals  all 
communicate  freely;  the  marrow  therefore  and  its  enclosing  cellular 
tissue  are  every  where  continuous. 

Periosteum. 
The  external  surface  of  all  bones,  with  the  exception  of  their  artic- 


BONE.  323 

ular  extremities,  is  covered  with  a  dense  membrane  composed  of 
fibrous  tissue,  which  is  very  rich  in  blood-vessels,  and  which  is  called 
the  periosteum. 

The  internal  surface  of  the  medullary  cavity,  cells,  and  larger 
Haversian  canals,  is  also  lined  by  a  vascular  membrane  much  more 
delicate  in  structure,  which  may  be  regarded  as  an  internal  periosteum. 

It  is  by  means  of  the  vessels  which  ramify  through  these  mem- 
branes that  the  nourishment  of  the  bone  is  secured. 

Vessels  of  Bone. 

Bones  are  richly  supplied  with  blood-vessels,  which  penetrate  every 
part  of  their  structure. 

Thus  externally,  branches,  principally  arterial,  proceed  from  the 
periosteum,  enter  the  numerous  apertures  of  the  Haversian  canals, 
and, ramifying  through  these,  form  a  capillary  net-work;  these  external 
periosteal  vessels  may  be  seen  with  the  unaided  eye,  extending  into 
the  bone  like  so  many  fine  threads,  on  the  cautious  detachment  of  the 
periosteum. 

Again,  in  the  long  bones,  a  large  artery  penetrates  by  an  oblique 
canal  situated  at  the  junction  of  their  upper'  and  middle  thirds,  into 
the  medullary  cavity,  and  sends  branches  upwards  and  downwards, 
which  ramify  on  the  membrane  of  the  medulla  or  internal  perios- 
teum; some  of  these  proceed  onwards  into  the  medullary  cells,  and 
others  inosculate  with  the  capillaries  of  the  Haversian  canals  already 
referred  to. 

The  flat  and  irregular  bones  are  furnished  not  with  a  single  vessel 
of  large  calibre,  but  with  several  of  smaller  size. 

These  larger  arteries  are  accompanied  by  veins,  whereby  a  portion 
of  the  venous  blood  is  returned  from  the  bone. 

Breschet,*  moreover,  has  described  in  the  flat  bones,  and  especially 
in  those  of  the  cranium,  a  system  of  osseous  canals,  which  contain 
only  veins,  and  which  are  furnished  with  valves,  which  is  not  the  case 
with  the  other  veins  of  bones. 

The  walls  of  these  canals,  which  ramify  after  the  manner  of  vessels, 
are  pierced  with  apertures,  by  which  they  receive  small  capillaries: 
they  traverse  principally  the  spongy  portion  of  bones,  afterwards  they 
pass  through  the  compact  part,  and  finally  terminate  on  the  external 
surface  of  the  bone. 

*  N.  A.  N.  C.  xxiii.  P.  i.  p.  361.;  Recherches  Anat.  Physwlog.  el  Pat.  sur  le  Sys- 
teme  Veineux,  Paris,  1829.  fol. 


324 


THE     SOLIDS 


These  canals  are  best  seen  in  the  flat  bones  of  the  cranium,  which 
should  be  dried,  and  the  outer  table  of  compact  substance  removed. 
Lymphatics  have  been  observed  in  some  few  instances  in  bone. 

Nerves  of  Bone. 

Nerves  have  not  hitherto  been  satisfactorily  traced  into  bones; 
nevertheless,  the  great  pain  experienced  in  diseased  conditions  of 
them  proves  incontestably  the  existence  of  nervous  fibrillee. 

GROWTH  AND  DEVELOPMENT  OF  BONE. 

Growth  of  Bone. — The  situations  in  which  the  chief  increase  of 
bone  occurs  are  commonly  stated  to  have  been  accurately  determined 
by  means  of  the  different  madder  experiments  instituted  by  numerous 
observers. 

If  an  animal  be  fed  for  a  short  time  with  the  root  of  madder,  its 
bones  will  become  tinged  with  the  colouring  matter  of  that  plant, 
between  which  and  the  phosphate  of  lime  of  the  bone  a  great  affinity 
exists. 

On  a  close  examination  of  sections  of  a  growing  long  bone  it  will 
be  observed,  however,  that  the  tissue  of  the  bone  is  not  uniformly 
coloured,  but  that  in  a  transverse  cutting  the  colour  is  principally 
situated  in  the  outer  part.  The  same  fact  is  shown  also  in  longitudi- 
nal sections,  which,  however,  if  they  embrace  the  entire  length  of  the 
bone,  will  also  be  observed  to  be  tinged  with  the  colouring  matter 
towards  either  extremity. 

Again,  if  a  magnifying  glass  be  applied  to  a  thin  transverse  section 
of  the  growing  bone  of  an  animal  fed  upon  madder,  each  Haversian 
canal  will  be  seen  to  be  surrounded  by  its  ring  of  colour.  For  this 
beautiful  illustration  of  the  effects  of  madder  we  are  indebted  to  Mr. 
Tomes.     (Plate  XXXIII.  fig.  6.) 

These  several  observations  have  been  presumed  to  prove  that  bones 
increase  in  length  principally  by  additions  of  new  matter  to  their 
extremities,  and  in  breadth  by  the  deposition  of  new  laminae  of  bone 
on  their  outer  surface,  as  well  as  by  the  formation  of  fresh  lamellae 
in  each  Haversian  canal,  which  last  grow  and  expand  in  size  simul- 
taneously with  the  laminae  placed  external  to  them  after  their  first 
formation. 

Now,  although  it  is  very  probable  that  bones  increase  in  diameter 
to  a  great  extent  by  the  addition  of  new  matter  on  the  external  sur- 
face, and  although  it  is  quite  certain  that  they  become  elongated  by 


BONE.  325 

the  formation  of  bony  matter  at  their  extremities,  it  appears  to  be 
most  clear  that  we  are  not  justified  in  coming  to  any  such  conclusion 
from  the  results  of  the  experiments  with  madder.  All  that  these  cel- 
ebrated experiments  really  seem  to  prove  is,  that  bones  in  contact 
with  blood-vessels  containing  the  colouring  matter  of  madder,  readily 
imbibe  and  retain  that  principle  in  common  with  the  liquor  sanguinis. 

The  bones  of  old  animals  are  coloured  with  much  more  difficulty 
than  those  of  young;  a  few  hours  in  very  young  animals  being  suffi- 
cient to  ensure  their  colouration. 

Development  of  Bone. — We  come  now  to  consider  the  exact  pro- 
cess of  the  development  of  bone. 

Bone  is  developed  either  in  membrane  or  in  cartilage ;  when  in  the 
former,  it  may  be  termed  intra-membranous,  and  when  in  the  latter, 
intra-cartilaginous  ossification. 

Intra-membranous  Form  of  Ossification. — We  will  consider,  first, 
the  intra-membranous  form  of  ossification.  Dr.  Nesbitt*  was  the  first 
to  distinguish  between  the  two  types  of  ossification.  More  recently 
Dr.  Sharpeyf  has  described  clearly  and  satisfactorily  the  steps  of  the 
intra-membranous  development.  This  form  he  considers  to  belong 
to  certain  flat  bones  of  the  cranium,  as  the  parietal  and  portions  of 
the  frontal  and  occipital  bones,  as  well  as  to  the  outer  surfaces  of  the 
long  bones. 

The  first  perceptible  ossification  of  the  parietal  bone,  which  may  be 
selected  as  one  of  the  best  examples  of  this  form  of  osseous  develop- 
ment, consists  of  a  net-work  of  spicula  of  bone,  the  outermost  of 
which  radiate  in  lines  towards  the  circumference,  and  are  connected 
by  short  transverse  branches.     (See  Plate  XXXIII.  figs.  1,  2.) 

As  the  ossification  proceeds,  the  first  formed  spicula,  in  the  centre 
of  the  bone,  become  greatly  increased  in  thickness,  and  the  spaces 
between  them  much  diminished  in  size;  the  ossification  continues 
thus  to  spread  and  consolidate  until  the  parietal  meets  the  neighbour- 
ing bone,  with  which  it  is  at  length  united  by  suture. 

If,  however,  the  microscope  be  brought  to  bear  upon  one  of  the 
newly-formed  spicula  before  the  entire  bone  has  attained  any  con- 
siderable development,  it  will  be  seen  that  the  ossific  deposit  takes 
place  in  the  fibres  of  fibro- cellular  tissue,  intermingled  with  which 
numerous  granular  and  nucleated  cells  occur;  these  fibres,  which  are 
disposed  in  bundles,  invariably  precede  the  deposition  of  bony  matter, 

*  Human  Osteogony,  Lond.  1736. 

f  Dr.  Quain's  Anatomy,  edited  by  Mr.  Quain  and  Dr.  Sharpey,  5th  edition. 


326  THE     SOLIDS. 

and  mark  out  the  course  of  the  future  spicula.      (See  Plate  XXXII. 

fig-  3.) 

The  granular  cells  just  noticed  have  been  observed  by  Dr.  Sharpey, 
who  remarks  upon  their  distribution  in  the  direction  of  the  future 
spiculse,  and  who  considers  that  they  are  connected  in  some  way  or 
other  with  the  process  of  ossification. 

There  can  scarcely  be  a  question  but  that  they  are  the  bone  cells 
in  a  rudimentary  state,  their  conversion  into  which  it  is  not  difficult 
to  trace. 

Now,  it  does  not  appear  that  cartilage  is  at  all  concerned  in  any 
one  stage  of  the  development  of  the  parietal  bone  of  the  human 
embryo.  In  that  of  the  sheep,  and  some  other  animals,  a  lamina  or 
cartilage  is  present  in  connexion  with  the  parietal  bone ;  but  this  takes 
no  part  in  the  process  of  ossification,  but  merely  serves  as  a  support 
to  the  newly-developed  bone,  and  extends  beneath  the  first-formed 
portion  of  it  alone. 

As  the  ossification  advances  still  further,  the  interstices  between 
the  first-formed  spicula  become  filled  up,  grooves  appear  on  the  sur- 
face of  the  bone;  these  radiate  from  the  centre  towards  the  circumfer- 
ence, and  ultimately  become  converted  into  canals,  which,  being  lined 
with  a  number  of  concentric  laminae,  at  length  constitute  the  com- 
plete Haversian  canals.     The  bone  is  then  completely  formed. 

Intra-cartilaginous  Ossification. — It  has,  until  recently,  been  sup- 
posed that  the  formation  of  bone  always  takes  place  in  cartilage;  this 
notion,  as  we  have  seen,  is  erroneous. 

Ossification  is  also  usually  described  as  the  conversion  of  cartilage 
into  bone;  this  idea  will  be  presently  shown  to  be  equally  erroneous, 
and  the  fact  demonstrated  that  the  intra-cartilaginous  ossification  does 
not  differ  essentially  from  the  intra-membranous  form. 

If  the  microscope  be  brought  to  bear  upon  a  thin  longitudinal  sec- 
tion of  an  ossifying  foetal  bone,  in  connexion  with  its  cartilaginous 
epiphysis,  the  following  particulars  will  be  noticed : 

First,  it  will  be  observed  that  the  cartilage  cells  in  the  neighbourhood 
of  the  bone,  instead  of  being  scattered  irregularly  throughout  the  inter- 
cellular substance,  are  arranged  in  several  consecutive  and  alternating 
rows  or  files,  the  lowermost  of  which  dip  into  and  are  surrounded  by 
osseous  cups  and  septa;  that  the  cells  forming  the  lower  portion  of 
the  lowest  tier  are  larger,  and  less  compressed,  than  those  which  enter 
into  the  formation  of  the  upper  part  of  each  lower  series,  and  that  they 
are  separated  from  each  other  by  distinct  portions  of  inter-cellular 


BONE.  327 

substance.  Secondly,  it  will  be  remarked  that  the  extremities  of  the 
still  soft  bony  spicula  invade  and  extend  into  the  spaces  which  inter- 
vene not  merely  between  the  rows  of  cells,  but  also  between  the  indi- 
vidual cells,  and  further,  that  granular  and  probably  cytoblastemic 
particles  are  deposited  in  this  inter-cellular  substance,  particularly 
where  this  comes  into  contact  with  the  cartilage  cells  themselves. 
(See  Plate  XXXIV.  figs.  1.  4.) 

As  the  process  of  ossification  advances,  the  cell-wall  of  the  cartilage 
cells  becomes  absorbed;  granular  corpuscles  are  next  generated  in 
the  primary  cancellus ;  after  which  the  nuclei  of  the  cartilage  cells 
(which  are  observed  to  become  smaller,  the  deeper  they  lie  in  the 
bone)  are  removed  by  absorption;  finally,  the  small  septa  intervening 
between  the  individual  cartilage  cells  are  removed,  the  larger  medul- 
lary spaces  being  thus  formed.     (See  Plate  XXXIV.  fig.  4.) 

Furthermore,  in  these  precursory  and  even  in  the  older  spicula, 
fibres  analogous  to  those  in  which  the  spicula  of  the  parietal  bones 
are  developed,  may  be  abundantly  detected. 

Such  is  a  brief  sketch  of  the  several  steps  of  the  intra-cartilaginous 
form  of  ossification. 

Now,  the  process  which  we  have  just  described,  is  constantly  in 
progress ;  cartilage  cells  on  the  one  side  are  continually  being  devel- 
oped in  the  epiphysis;  they  are  also  constantly  marshalling  themselves 
into  rows  or  columns,  the  lowermost  cells  of  which  dip  into  the  can- 
celli  and  become  absorbed  ;  on  the  other  side,  the  cancelli  of  the  bone 
are  continually  invading  the  inter-cellular  spaces  of  the  cartilage. 

It  is  thus  that  a  bone  grows  in  length.  Each  epiphysis  of  a  long 
bone,  however,  after  a  time,  becomes  a  centre  of  ossification;  this 
proceeds  to  meet  that  of  the  shaft;  a  layer  of  cartilage  usually,  how- 
ever, intervenes  between  the  two,  until  the  period  of  the  full  develop- 
ment of  the  osseous  system,  when  this  layer  becomes  absorbed,  and 
the  shaft  and  the  epiphysis  become  consolidated  by  bony  union.  The 
first  trace  of  ossification  of  the  epiphysis  in  the  human  subject  is 
usually  apparent  at  about  the  ninth  month. 

We  have  now  to  ask  ourselves  the  question,  how  does  the  bone 
increase  in  diameter?  We  have  shown  that  it  is  generally  considered, 
as  proved  by  the  madder  experiments  already  referred  to,  that  a  long 
bone  increases  in  breadth  by  the  deposition  of  new  lamellae  at  the 
circumference,  as  well  as  in  the  cavities  of  ihe  medullary  and  Haver- 
sian canals;  but  we  have  seen  also  from  what  has  been  already  said 
in  reference  to  the  different  sizes  of  the  external  and  internal  Haver- 


328  THE     SOLIDS. 

sian  canals  and  their  mode  of  formation,  that  each  of  these  canals  is 
continually  undergoing  a  process  of  expansion,  and  it  is  by  this 
expansion  that  the  chief  increase  of  the  diameter  of  a  bone  takes  place. 
It  was  formerly  supposed  that  a  layer  of  cartilage  existed  in  all  grow- 
ing bones  on  their  external  surfaces,  but  we  now  know  that  such  is 
not  the  case,  and  that  the  new  osseous  deposit  takes  place  in  fibres. 
If  it  were  necessary  that  a  layer  of  cartilage  should  exist  in  the  situ- 
ation named,  it  would  be  equally  requisite  that  it  should  be  present  in 
each  medullary  cell,  and  in  each  Haversian  canal. 

The  small  granular  corpuscles  already  referred  to  as  occurring  in 
the  cancelli  of  all  bones,  but  especially  in  those  of  the  foetus,  it  would 
thus  appear  are  developed  in  considerable  quantities  at  a  very  early 
period  of  the  development  of  bone ;  they  are  generally  apparent  in  the 
third  or  fourth  tier  of  the  first  formed  and  small  cancelli,  and  while 
the  nuclei  of  the  cartilage  cells  yet  exist.     (See  Plate  XXXV.  fig.  3.) 

It  will  now  be  perceived  that  the  intra-cartilaginous  form  of  ossifi- 
cation is  identical  with  the  intra-membranous  type  in  all  essential 
particulars. 

It  will  also  readily  be  seen  that  this  view  of  the  process  of  ossifi- 
cation differs  very  considerably  from  the  more  recently  expressed 
opinions  on  the  subject ;  those,  for  example,  of  Drs.  Todd  and  Bow- 
man, and  of  Mr.  Tomes. 

The  authors  of  the  "Physiological  Anatomy"  consider  that  the 
nuclei  of  the  cartilage  cells  become  developed  ultimately  into  the 
bone  cells. 

There  are  many  considerations  which  would  lead  to  the  conclusion 
that  such  a  transformation  is  but  little  probable,  the  following  of 
which  may  be  referred  to: 

The  formation  of  bone,  independent  of  cartilage,  as  in  the  intra- 
membranous  type  of  ossification. 

The  small  number  of  the  cartilage  cells,  compared  with  the  vast 
quantities  of  bone  cells  which  exist  in  even  a  young  bone. 

The  impossibility  of  explaining  why  the  permanent  cartilages 
should  not,  like  the  temporary,  be  constantly  subject  to  ossification, 
since  they  are  both  organized  in  precisely  the  same  manner. 

The  proof  that  cartilage  cells  have  no  further  stage  of  development 
to  pass  through,  manifested  by  the  fact  of  the  occurrence  of  parent 
cells  in  all  cartilages,  whether  temporary  or  permanent. 

The  chief  new  points  contained  in  Mr.  Tomes's  views*  are  the 
*  See  Art.  "  Osseous  Tissue,"  Cyclop  of  Anatomy  and  Physiology. 


BONE.  329 

ossification  of  the  walls  of  the  several  cartilage  cells  which  form  each 
roll  or  column,  and  the  conversion  of  a  number  of  these,  by  the 
absorption  of  the  contiguous  walls  of  the  cells  into  a  single  cavity  or 
tube,  which  becomes  filled  with  a  granular  blastema;  this  tube  Mr.  T. 
considers  to  be  an  Haversian  canal,  and  its  wall  to  constitute  ulti- 
mately the  outer  lamina  of  such  canal. 

The  arguments  adduced  in  disproof  of  the  opinion  that  the  nuclei 
of  the  cartilage  cells  become  converted  into  bone  corpuscles,  apply 
with  equal  force  against  the  idea  of  the  calcification  of  the  walls  of 
the  cartilage  cells. 

Bone  Cells. — Bone  cells,  then,  according  to  the  views  of  the  author, 
are  not  transformed  nuclei  of  cartilage  corpuscles,  but  take  their 
origin  in  distinct  granular  cells,  which  may  be  clearly  seen  in  the 
growing  spiculae  of  bone  dispersed  among  the  fibres  in  which  the 
earthy  matter  of  bone  is  first  deposited,  and  which  at  length  become 
entirely  imbedded  in  the  earthy  deposition. 

As,  however,  it  is  most  probable  that  a  development  of  bone  cells 
and  new  laminae  of  bone  are  ever  in  progress  even  in  adult  bones, 
we  should  expect  to  encounter  in  the  cancelli  of  bones  of  every  age 
fibres  of  cellular  tissue  and  granular  cells;  both  these  do  occur  in 
them,  and  especially  the  latter,  which  are  met  with  in  great  numbers. 

These  granular  nucleated  cells  are  more  numerous  in  foetal  and 
young  bones  than  in  those  of  older  formation ;  in  the  former,  indeed, 
they  almost  entirely  fill  up  the  cavities  of  the  cancelli :  in  the  latter, 
although  they  are  still  numerous,  their  place  is  supplied  with  fat 
vesicles,  which  are  not  present  in  the  former. 

It  seems  to  me  to  be  not  improbable  that  two  kinds  of  granular 
cells  may  exist  in  the  medullary  spaces,  &c,  one  consisting  of  rudi- 
mentary bone  cells,  and  the  other  connected  with  the  elaboration  of 
marrow,  which  occupies  the  medullary  cavity,  medullary  cells,  and 
larger  Haversian  canals. 

It  might  be  supposed  that  these  granular  cells  were  the  white  cor- 
puscles of  the  blood  escaped  from  the  ruptured  vessels,  the  red  blood 
discs  having  been  absorbed ;  this  notion  is,  however,  disproved  by  the 
fact  that  many  of  them  are  much  larger  than  the  colourless  corpus- 
cles of  the  blood.     (See  Plate  XXXIII.  Jig.  5.) 

The  existence  of  a  granular  blastema  in  the  cancelli,  &c,  of  bones 
was  first  observed  by  Drs.  Todd  and  Bowman,*  who  considered  that 
it  was  concerned  in  the  development  of  blood-vessels. 

*  Physiological  Anatomy,  chap.  v. 


330  THE     SOLIDS. 

Presuming  it  to  be  proved  that  the  bone  cells  are  derived  from  true 
corpuscles,  we  have  yet  to  decide  whether  we  are  to  believe  with 
Schwann,*  that  they  are  complete  cells,  and  that  the  canaliculi  are 
prolongations  of  the  walls  of  these  cells ;  that,  in  fact,  they  possess  a 
structure  conformable  with  that  of  the  stellate  pigment  cells  of  the 
skin  of  the  frog,  or  of  the  lamina  fusca  of  the  eye ;  whether  we  are 
to  consider  with  Gerber,f  Bruns,J  and  E.  H.  Mayer,§  that  they  are 
the  nuclei  of  primitive  elementary  cells,  and  that  the  canaliculi  are 
prolongations  of  these;  whether,  again,  we  are  to  regard  them  with 
Henle||  as  the  cavities  of  cells,  the  walls  of  which  have  become 
thickened,  and  the  canaliculi  of  which  proceed  from  the  central  cavity 
through  the  thickened  walls  of  the  cells,  as  do  the  porous  canals  of 
many  vegetable  cells;  lastly,  whether  we  are  to  believe,  with  Todd 
and  Bowman,  that  the  canaliculi  proceed  from  the  nucleus,  which 
afterwards  becomes  absorbed,  and  that  thus  the  lacuna  is  left. 

That  the  first  view  is  the  correct  one,  and  that  the  bone  cells  are 
to  be  regarded  as  complete  corpuscles,  the  canaliculi  of  which  are 
formed  by  the  extension  of  the  cell  wall,  is,  I  think,  proved  by  watch- 
ing the  formation  and  development  of  bone  cells  in  growing  spiculae 
and  by  the  action  of  dilute  hydrochloric  acid,  which,  by  removing 
the  earthy  matter,  allows  the  granular  texture,  which  originally  char- 
acterized them,  to  be  again  seen. 

The  last  points  left  for  consideration  in  reference  to  the  develop- 
ment of  bone  are,  the  modes  of  formation  of  the  medullary  cavity, 
medullary  cells,  and  Haversian  canals. 

Formation  of  Medullary  Cavity. — Traversing  the  substance  of 
each  cartilaginous  epiphysis,  a  number  of  large  and  branched  canals 
may  be  seen  in  both  transverse  and  longitudinal  sections.  (See  Plate 
XXXV.  figs.  1,  2.) 

The  majority  of  these  proceed  directly  from  the  ossified  part  of 
the  shaft  in  connexion  with  the  epiphysis ;  in  this  situation  they  are 
of  larger  size,  and  are  also  fewer  in  number,  than  they  are  higher  up 
in  the  epiphysis,  not  exceeding  usually  five  or  six,  but  becoming  multi- 
plied, by  the  giving  off  of  branches,  to  as  many  as  fourteen  or  sixteen ; 
others,  however,  enter  the  epiphysis  from  the  sides,  near  the  junction 
of  the  bone  and  cartilage. 

The  interior  of  these  canals  is   occupied  with  blood-vessels  and 

*  Mikroskopische  Untersuchungen,  pp.  35.  115. 

f  Allgemeine  Anaiomie,  p.  104.  \Ibid.  pp.  240.  252. 

\  Miiller,  Archie.  1841,  p.  210.  II  Anal.  Gen.  t.  vii.  p.  409. 


BONE.  331 

with  granular  nucleated  cells,  precisely  like  those  existing  in  the 
medullary  cells  of  bone.     (See  Plate  XXXV.  fig.  3.) 

The  cartilage  cells  in  a  transverse  section  of  the  canals  immediately 
surrounding  their  orifices  are  disposed  in  a  rayed  manner. 

Having  thus  described  the  structure,  contents,  and  distribution  of 
these  canals,  we  will  next  inquire  their  use.  (See  Plate  XXXV. 
tig.  3.) 

If  a  number  of  transverse  sections  be  made,  not  merely  of  the 
cartilaginous  epiphysis,  but  also  of  the  bone  in  connexion  with  it, 
and  if  these  be  examined  in  the  order  of  their  removal,  it  will  be 
observed,  first,  that  in  those  sections  which  are  made  from  the  cartil- 
aginous epiphysis  most  removed  from  the  bone,  the  apertures  of 
these  canals  are  small  and  numerous  (see  Plate  XXXV.  fig.  1) ; 
second,  that  in  the  sections  taken  from  the  proximal  end  of  the  epiph- 
ysis the  canals  are  fewer  in  number  and  their  orifices  larger  (see 
Plate  XXXV.) ;  thirdly,  that  in  other  slices,  which  include  a  portion 
of  both  cartilage  and  bone,  the  latter  always  commences  on  the 
circumference  of  the  section,  proceeding  gradually  inwards,  the 
portion  of  cartilage  surrounding  the  canals  in  question  being  the  last 
to  become  ossified  (see  Plate  XXXV.  figs.  2,  3) ;  fourthly,  in 
cuttings  made  below  the  cartilage  and  through  the  bone,  spaces  four 
or  five  in  number,  filled  with  granular  cells  corresponding  in  situation 
with  the  afore-described  canals,  will  be  observed;  fifthly,  in  others 
carried  still  deeper  into  the  bone,  these  several  apertures  will  have 
coalesced  into  one  large  space — the  rudimentary  medullary  cavity. 

From  these  several  particulars,  I  therefore  infer  that  the  canals  in 
question  are  intimately  connected  with  the  formation  of  the  medullary 
cavity ;  and  that  the  absorption  of  the  cancelli  situated  between  each 
of  them  is  brought  about  by  the  vessels  contained  within  them,  aided 
also  probably  by  the  granular  cells. 

Were  the  canals  merely  destined  to  convey  to  the  cartilage  the 
nourishment  necessary  for  its  transformation  into  bone,  it  might  be 
expected  that  they  would  serve  as  so  many  centres  from  which  the 
ossification  would  proceed ;  we  have  seen,  however,  that  the  cartilage 
in  their  immediate  vicinity  is  the  last  to  be  removed,  and  its  place 
supplied  by  bony  cancelli. 

Medullary  Cells. — The  primary  cancelli  are  small,  studded  with 
granules,  form  closed  cavities,  and  do  not  contain  bone  cells.  (See 
Plate  XXXIV.  figs.  2,  3.)  The  secondary  and  larger  cancelli  are 
formed  by  the  absorption  of  the  numerous  septa  of  the  primary 


332  THE     SOLIDS. 

cancelli ;  they  do  not  form  closed  cavities,  but  communicate  freely 
together,  and  contain  bone  cells  imbedded  in  their  parietes.  (See 
Plate  XXXIV.  fig.  4.)* 

Haversian  Canals. — The  Haversian  canals  are  generally  described 
as  being  formed  by  the  filling  up  of  certain  of  the  medullary  cells,  in 
consequence  of  the  successive  deposition  of  new  laminae  of  bony 
matter.  It  seems  to  me,  however,  to  be  very  questionable  whether 
they  are  formed  in  the  manner  indicated,  and  if  so,  such  is  assuredly 
not  the  general  mode  of  their  formation. 

I  am  induced  to  take  a  different  view  of  their  formation,  and  con- 
sider they  originate  as  follows : 

The  surface  of  all  bones,  whether  long,  flat,  or  irregular,  is  observed 
to  be  marked  with  numerous  grooves  of  different  sizes  and  depths. 
In  the  recent  state,  these  are  occupied  with  blood-vessels,  and  it  is 
around  them  that  successive  layers  of  bone  are  deposited,  until  at 
length  the  vessels  become  entirely  included,  and  a  perfect  canal  is 
formed. 

In  transverse  sections  of  long  bones,  grooves  and  partially  developed 
canals  may  generally  be  seen  along  the  outer  margin  of  the  cutting. 

This  view  of  the  formation  of  the  Haversian  canals  also  accords 
well  with  other  characters  presented  by  transverse  sections  of  bone. 
Thus,  in  all  such,  it  will  be  seen  that  the  smallest  Haversian  canals 
are  situated  in  the  external  part,  while  the  larger  canals  are  placed 
internal  to  these :  it  will  also  be  observed,  that  the  smaller  canals  are 
surrounded  by  the  fewest  number  of  concentric  lamellae,  and  the 
larger  by  the  greatest  number.  (See  Plate  XXXII.  fig.  1.)  Now,  the 
fact  of  an  additional  number  of  lamellae  encircling  the  larger  canals 
proves  two  things:  first,  that  these  large  Haversian  channels  are  of 
older  formation  than  the  small;  and  second,  that  each  lamella  grows 
or  expands  after  its  deposition,  whereby  the  calibre  of  such  canals 
becomes  increased,  which  is  contrary  to  the  generally  entertained 
notion  of  the  formation  of  the  Haversian  canals,  viz :  by  the  filling  up 
of  the  large  cancelli,  brought  about  by  the  continual  deposition  of 
new  osseous  lamellae,  the  outermost  of  which,  for  such  a  result  to 
ensue,  must  remain  stationary  in  point  of  size. 

ACCIDENTAL    OSSIFICATION. 

The  abnormal  growth  and  development  of  bone  is  a  very  common 
pathological  occurrence.     Thus,  we  have  it  occurring  on  the  surface 

*  See  No.  x.  Med.  Chir.  R.  p.  528. 


BONE.  383 

of  the  bones  themselves  in  the  form  of  exostoses,  in  the  permanent 
cartilages,  in  the  cellular  tissue  of  muscles,  glands,  the  ovaries,  mem- 
branes, as  the  coats  of  the  arteries,  and  probably  occasionally  also 
in  that  of  every  other  tissue  and  organ  of  the  body. 

It  is  not,  however,  every  ossific  deposit  which  presents  all  the 
characters  of  bone:  thus,  those  contained  in  the  ovaries,  in  the 
mesenteric  glands,  and  in  the  coats  of  the  arteries,  usually  want  the 
more  conspicuous  elements  of  bone,  the  bone  cells  and  lamellae, 
although  these  have  been  met  with  in  ossific  depositions  remote  from 
all  connexion  with  bone. 

In  the  reparation  of  fractures,  we  have  a  development  of  true  bone 
preceded  by  the  formation  of  cartilage. 


334  TH"E     SOLIDS. 


BONE. 


[Longitudinal  and  transverse  sections  of  bone,  to  display  the  true  struct- 
ure, require  so  much  time  and  trouble  in  the  preparation,  that  when  it  is 
possible  to  purchase  them,  this  course  will  be  found  to  be  more  advisable. 
For  those  who  desire  to  make  their  own  preparations,  the  following  instruc- 
tions are  added  : 

A  section,  either  longitudinal  or  transverse,  having  been  made  as  thin  as 
possible  with  a  fine  saw,  it  must  be  reduced  still  farther  by  a  flat  file. 

When  this  process  cannot  be  farther  carried  on,  the  section  is  to  be  placed 
between  two  hones,  and  being  kept  moistened  with  water,  the  honing  is  to 
be  pursued  until  the  section  becomes  sufficiently  thin  to  show  the  structure. 
This  point  should  be  ascertained  by  occasional  observations  with  a  low  power 
of  the  microscope.  When  sufficiently  reduced,  the  section  may  be  polished 
by  carefully  rubbing  it  on  a  strip  of  chamois-leather  with  putty-powder. 

If  it  be  very  thin,  it  should  be  mounted  dry ;  in  this  condition,  a  good  pol- 
ish will  much  increase  its  value;  but  if  the  section  be  not  very  thin,  it 
should  be  made  more  transparent  by  being  mounted  in  balsam;  in  this 
method,  no  polish  will  be  necessary. 

Mr.  Quekett  has  observed  that  in  some  instances  when  the  bone  was 
deposited  in  balsam,  and  heat  then  applied  until  the  balsam  has  boiled,  the 
structure  of  the  bone  has  been  beautifully  displayed. 

Sections  of  bone,  before  being  mounted,  should  be  cleansed  from  grease 
and  dirt  by  being  soaked  for  some  hours  in  sulphuric  ether. 

"  The  vessels  of  bone  may  be  recognised  while  it  is  yet  fresh  by  the  colour  of  the 
blood  contained  in  them,  but  they  are  rendered  much  more  conspicuous  by  injecting 
a  limb  with  size  and  vermilion,  depriving  the  bones  of  their  earth  by  means  of  an 
acid ;  then  drying  and  putting  them  into  oil  of  turpentine,  by  which  process,  the 
osseous  tissue  is  rendered  transparent,  while  the  injected  matter  in  the  vessels  retains 
its  red  colour  and  opacity."* 

As  already  stated  in  the  text,  the  lamellae  are  easily  separated  by  macera- 
tion in  dilute  hydro-chloric  acid.] 

*  "Quain's  Anatomy,"  by  Sharpey  and  Quain,  5th  ed. 


TEETH.  335 


ART.    XVI.  — THE     TEETH. 

The  tissue  of  the  teeth  is  to  be  regarded  rather  as  a  modification 
of  the  osseous,  than  as  a  distinct  type  of  structure :  the  truth  of  this 
remark  is  especially  apparent  on  an  examination  of  two  of  the  three 
substances  which  enter  into  the  formation  of  each  tooth,  viz:  the 
cementum  and  dentine ;  the  third  constituent,  the  enamel,  is  more 
nearly  related  in  its  organization  to  the  epithelium,  of  which  indeed 
it  is  a  condition. 

Each  tooth  consists  of  two  parts:  the  body  or  crown,  and  the  root 
or  fang;  the  limits  of  these  are  indicated  by  a  slight  contraction 
called  the  neck;  the  crown  is  either  simple  or  divided,  and  the  same 
is  the  case  with  root  also :  those  teeth  which  have  a  simple  crown  are 
called  incisors  and  canines,  those  with  a  double  crown  bicuspids,  and 
those  with  the  crown  quadruply  divided  molars.  Again,  the  sub- 
stance of  each  tooth  is  divisible  into  three  portions,  each  of  which 
presents  characteristic  differences;  these  have  received  the  names  of 
dentine,  cementum,  and  enamel. 

The  dentine,  also  called  the  ivory,  forms  the  chief  bulk  of  the  tooth, 
occupies  a  central  position,  and  its  interior  contains  the  pulp  cavity. 

The  enamel  forms  a  layer  of  compact  substance,  which  immediately 
surrounds  that  portion  of  the  dentine  of  which  the  crown  of  the 
tooth  is  made  up. 

The  cementum,  also  called  crusta  petrosa,  has  a  distribution  the 
very  reverse  of  the  enamel,  and  extends  principally  around  the  fangs 
of  the  teeth,  and  terminates  at  the  neck  of  the  tooth,  in  fact,  just 
where  the  enamel  commences. 

STRUCTURE    OF    THE    TEETH. 

Having  thus  sketched  the  general  position  of  the  three  constituents 
of  the  teeth,  the  consideration  of  the  intimate  structure  of  each  may 
next  be  entered  upon. 

Dentine. — The  dentine  is  constituted  of  numerous  tubes  imbedded 
in  an  inter-tubular  substance;  these  tubes  commence  at  the  pulp 
cavity,  on  the  surface  of  which  they  open,  and  from  which  they 
proceed  in  a  radiate  manner,  terminating  on  the  borders  of  the 
dentine ;  those  arising  from  the  upper  part  of  this  cavity  ascend  almost 
vertically,  those  from  the  sides  more  obliquely,  and  those  from  the  lower 
portion  pass  either  horizontally  outwards,  or  else  descend  somewhat. 


336  THE     SOLIDS. 

These  tubes  diminish  in  size  from  their  commencement  to  their 
termination:  they  are  branched;  at  first  they  divide  in  a  dichotomous 
manner;  their  subsequent  ramifications  are  numerous,  minute  and 
arborescent,  and  they  inosculate  freely  with  the  similar  branches 
proceeding  from  the  adjacent  tubes :  those  tubes  which  proceed 
towards  the  cementum  are  remarkable  for  the  very  great  number  of 
branches  into  which  they  divide. 

The  tubes  of  the  dentine  in  their  passage  outwards  do  not  run  in 
straight  lines,  but  describe  in  their  transit  two  or  three  large  curves, 
and  each  of  these  primary  curves,  when  examined  with  a  higher 
power  of  the  microscope,  will  be  observed  to  be  made  up  of  numerous 
smaller  and  secondary  curves ;  both  the  large  and  small  curvatures 
of  one  tube  correspond  with  those  of  another. 

Such  is  the  usual  course  and  distribution  of  the  tubes  of  the  dentine : 
several  modifications  of  them,  however,  still  remain  to  be  noticed. 

Thus,  sometimes  a  tube  in  its  passage  will  dilate  into  a  bone  cell, 
and  again  proceed  onwards  to  its  destination  as  a  tube;  at  others,  a 
number  of  them,  even  in  the  centre  of  the  dentine,  will  break  up  and 
form  a  cluster  of  bone  cells;  again,  at  others,  the  tubes  frequently 
become  transformed  into,  or  terminate  on  the  margin  of  the  dentine 
in  bone  cells.  This  gradual  transformation  of  the  dentinal  tubes  into 
bone  corpuscles,  and  their  termination  in  the  same,  is  especially  seen 
in  that  portion  of  the  dentine  contiguous  to  the  cementum. 

The  usual  method  of  termination  of  the  dentinal  tubes,  is  in  fine 
and  inosculating  branches  on  the  surface  of  the  dentine.  Sometimes, 
however,  the  tubes  anastomose  in  a  peculiar  manner,  and  form  distinct 
loops;  at  others,  the  terminal  branches  pass  out  of  the  dentinal  sub- 
stance, and  extend  either  into  the  cementum  or  the  enamel;  this 
extension  into  the  former  is  a  very  frequent  occurrence. 

For  illustrations  of  these  several  modifications,  the  majority  of 
which  have  been  pointed  out  by  Mr.  Tomes,  in  his  excellent  lectures,* 
see  the  figures. 

The  surface  of  the  dentine  presents  many  elevations  and  depres- 
sions :  to  these  the  enamel  is  accurately  adapted ;  it  also  exhibits  the 
hexagonal  impressions  of  the  enamel  fibres. 

The  substance  of  the  dentine  is  seen  also  occasionally  to  be  trav- 
ersed with  canals  for  blood-vessels,  analogous  to  the  Haversian  canals 
of  bone. 

*  See  "  Lectures"  in  Medical  Gazette. 


TEETH.  337 

The  pulp  cavity  of  the  teeth  of  old  persons  frequently  becomes 
filled  up,  and  even  obliterated,  by  a  secondary  formation  of  dentinal 
substance,  and  which  may  be  called  the  secondary  dentine.  This 
dentine  results  from  the  ossification  of  the  pulp  by  the  vessels  of  which 
it  is  ttaversed,  and  from  the  margins  of  the  canals  containing  which 
the  dentinal  tubes  proceed  in  a  radiate  manner.     (See  the  figures.) 

Mr.  Nasmyth  regarded  this  secondary  dentinal  formation  as  dis- 
tinct from  the  other  structures  of  the  tooth,  and  called  it  the  fourth 
dentinal  constituent. 

The  dentinal  tubes  form  but  one  element  of  the  dentine ;  the  other 
is  the  inter-tubular  substance. 

This  is  described  by  Mr.  Nasmyth  as  constituted  of  elongated  cells, 
in  the  form  of  bricks  placed  end  to  end,  and  a  tier  of  which  exists 
between  every  two  tubes :  Henle,  on  the  other  hand,  declares  it  to  be 
fibrous.  It  would  appear  not  to  present  any  regular  tissue,  but  to  be 
simply  granular. 

Occasionally,  I  have  encountered  in  it  globules  of  various  sizes 
refracting  the  light  strongly,  and  presenting  the  appearances  of  oil  or 
fat  vesicles.  It  has  occurred  to  me  that  these  might  be  fat  cells 
which  had  become  included  in  consequence  of  the  ossification  of  the 
pulp,  and  which  always  contains  a  greater  or  less  quantity  of  fat 
cells.     (See  figure.) 

Some  sections  of  dentine  which  I  have  examined  have  exhibited 
numerous  reticulated  markings,  the  results  of  fracture  of  the  inter- 
tubular  tissue,  and  occasioned  probably  by  the  preparation  of  the 
section.     Fracture  of  the  dentine  is  capable  of  reunion. 

Cementum. — Of  the  cementum  it  will  not  be  necessary  to  say  very 
much,  it  possessing  the  structure  of  bone,  and  containing  both  bone 
cells  and  Haversian  canals;  the  latter,  however,  but  seldom.  (See 
the  figures.) 

The  quantity  of  cementum  differs  in  different  teeth ;  in  many  cases 
it  is  very  inconsiderable,  but  it  usually  increases  with  age. 

In  those  cases  in  which  there  is  but  a  slight  development  of 
cementum,  a  layer  of  considerable  thickness,  formed  of  numerous  more 
or  less  hexagonal  cells,  and  extending  over  the  whole  of  that  portion  of 
the  dentine  not  covered  by  enamel,  may,  in  most  cases,  be  clearly  seen. 

This  layer,  Mr.  Tomes  speaks  of  as  a  granular  layer;  it  is,  however, 
distinctly  and  regularly  cellular.  It  is  not  easy  to  decide  whether  it 
should  be  regarded  as  a  distinct  and  permanent  structure  of  the  tooth,  or 

22 


338  THE     SOLIDS. 

whether  it  merely  forms  the  basement  substance  in  which  the  cementum 
is  developed;  my  own  impressions  incline  to  the  former  view.* 

A  layer  of  granules,  having  the  aspect  of  imperfectly  developed 
bone  cells,  is  usually  situated  apparently  between  the  dentine  and 
cementum,  but  really  in  the  substance  of  one  or  other  of  these;  this 
layer  might  well  be  called  the  granular  layer,  and  to  it  the  description 
of  Mr.  Tomes  seems  more  applicable. 

Mr.  Nasmythf  describes  the  cementum  as  passing  over  the  entire 
surface  of  the  enamel  of  the  tooth ;  this  would  appear,  so  far  as  the 
human  tooth  is  concerned,  to  be  an  error.  A  cellular  lamina,  how- 
ever, does  really  invest  the  enamel  in  very  young  teeth,  but  this  is 
soon  worn  away:  this  layer,  however,  has  nothing  to  do  with  the 
cementum,  but  is  considered  by  Mr.  Tomes  to  be  derived  from  the 
inner  surface  of  the  membrane  of  the  tooth  sac.  It  may  be  seen  in 
the  teeth  of  the  calf  and  horse. 

Cementum  is  rarely,  if  ever,  developed  in  the  pulp  cavity,  although 
it  has  been  stated  to  be  so  by  many  observers.  The  cementum  is  not 
unfrequently  traversed  by  tubes,  similar  to  and  derived  from  those  of 
the  dentine. 

It  will  now  be  very  evident  that  dentine  and  cementum  do  not 
differ  essentially  from  each  other,  and  that  both  are  but  modifications 
of  ordinary  bone. 

Enamel. — Examined  with  an  object-glass  of  one-fourth  of  an  inch 
focus,  the  enamel  exhibits  a  fibrous  appearance. 

The  fibres  radiate  outwards  from  the  surface  of  the  dentine,  some- 
what in  the  same  manner  as  do  the  dentinal  tubes  themselves;  they 
are  simple,  short,  somewhat  attenuated  towards  either  end,  and  pass 
towards  the  margin  of  the  enamel  in  a  waved  manner,  sometimes 
decussating,  forming  plaits  or  folds,  and  this  occurs  especially  when 
the  surface  of  the  dentine  is  concave.  Viewed  with  a  glass  of  the 
eighth  of  an  inch  focus,  they  present  the  appearance  of  elongated  and 
many-sided  crystals,  and  in  transverse  sections  they  are  seen  to  be 
hexagonal  or  polygonal ;  in  some  instances,  however,  and  especially 

*  The  following  is  Mr.  Tomes's  description  of  this  layer :  "  In  the  inter-tubular 
tissue,  hemispherical  or  elliptical  cells  are  found,  especially  near  the  surface  of  the 
dentine  of  the  fang,  where  they  form  a  layer  joining  the  cement.  This,  in  a  paper 
read  before  tbe  Royal  Society,  I  described  as  the  granular  layer;  on  the  coronal  sur- 
face of  the  dentine  they  are  not  numerous.  With  these  cells  the  dentinal  tubes  com- 
municate, as  do  others  coming  from  the  cemental  cells." 

f  Memoir  read  before  the  Medico-Chirurgical  Society,  by  Alexander  Nasmyth,  Jan. 
22d,  1839. 


TEETH.  339 

in  the  enamel  fibres  of  young  teeth,  a  minute  canal  may  be  traced 
running  along  each  fibre.     (See  the  figures.) 

It  is  uncertain  whether  each  fibre  is  constituted  of  a  single  cell,  or 
whether  several  unite  to  form  it :  the  appearance,  in  some  cases,  of 
faint  transverse  markings  would  render  it  probable  that  the  latter 
opinion  is  the  correct  one. 

Near  the  surface  of  the  dentine,  linear  interspaces  may  sometimes 
be  noticed  between  the  enamel  fibres;  with  these  spaces  the  tubuli 
of  the  dentine  frequently  communicate,  and  when  they  exist  in  any 
number,  or  extend  nearly  through  its  entire  thickness,  they  produce 
a  pearly  appearance  of  the  enamel,  and  render  it  brittle. 

Thin  longitudinal  sections  of  the  enamel,  in  connexion  with  the 
dentine,  generally  exhibit  numerous  linear  fractures,  which  extend 
through  its  entire  thickness,  and  which  most  probably  arise  from 
their  mode  of  preparation.  Sections  of  enamel  also  usually  present 
numerous  wavy  lines,  and  which  are  occasioned  by  the  instrument 
employed  in  making  the  cuttings. 

Structure  of  the  Pulp. 

The  centre  of  the  dentine  of  all  teeth  is  hollowed  out  into  a  cavity; 
this  is  occupied  with  a  soft  and  reddish  mass,  easily  separable  from 
the  walls  of  the  cavity,  the  pulp. 

The  pulp  is  made  up  of  numerous  blood-vessels,  the  walls  of  which 
are  constituted  of  delicate  and  nucleated  cells,  of  nerves,  or  ganglionic 
cells,  and  larger  granular  cells  placed  principally  on  the  surface  of  the 
pulp,  external  to  the  other  structures  which  enter  into  its  formation. 

These  external  granular  cells  are  supposed  to  play  an  important 
part  in  the  development  of  the  dentine,  and  to  which  more  particular 
reference  will  be  made  hereafter. 

The  pain  experienced  in  tooth-ache  arises  from  inflammation  of  the 
nerves  of  the  pulp,  and  which  is  frequently  left  exposed  to  the  contact 
of  the  air  in  consequence  of  the  removal  of  the  dentine,  by  which  in 
sound  teeth  it  is  enclosed,  as  the  result  of  caries. 

DEVELOPMENT    OF    THE    TEETH. 

The  subject  of  the  development  of  the  teeth  may  be  considered 
under  two  heads :  under  the  first,  the  general  development  of  the  teeth 
will  be  briefly  noticed;  and  under  the  second,  the  special  develop- 
ment of  their  several  constituents  will  be  treated  of. 

Into  the  various  particulars  in  reference  to  the  general  develop- 


340  THE     SOLIDS. 

ment  of  the  teeth  as  organs,  it  would  be  inconsistent  with  the  design 
of  this  work  to  enter  at  any  length.  It  will  be  sufficient  to  observe, 
that  preparations  are  made  for  the  formation  of  the  milk  teeth  at  a 
very  early  period  of  intra-uterine  life  ;  that  the  first  trace  of  the  future 
tooth  is  manifest  in  the  form  of  a  papilla  placed  in  the  primary  dental 
groove,  and  consisting  of  granular  and  nucleated  cells ;  that  around 
this  papilla  a  membrane  is  developed,  with  an  open  mouth,  thus  form- 
ing a  follicle;  from  the  margins  of  this  aperture  processes  of  the 
mucous  membrane,  of  which  the  follicle  is  constituted,  are  developed, 
and  these  uniting  with  each  other  close  the  opening,  and  convert  the 
follicle  into  a  sac.  With  the  closure  of  the  mouth  of  the  follicle,  the 
first  or  follicular  stage  of  the  development  of  the  teeth  is  terminated, 
and  the  second  or  saccular  stage  commences.  The  number  of  oper- 
cula  developed  from  the  margins  of  the  follicles  is  determinate,  being 
two  for  the  incisives,  three  for  the  canines,  and  four  or  five  for  the 
molars.  In  the  second  or  saccular  stage,  the  papilla  takes  the  form 
of  the  tooth,  of  which  it  is  the  representative,  the  base  dividing  in  the 
case  of  the  molars  into  fangs,  and  its  apex  assuming  the  shape  of  the 
crown  of  the  tooth,  in  the  place  of  which  it  stands :  in  this  stage  also 
a  blastemic  matter,  consisting  of  plasma  and  nucleated  cells,  is  devel- 
oped in  the  space  intervening  between  the  papilla  and  the  sac,  and 
adherent  to  the  inner  surface  of  the  membrane  of  the  latter,  by  which, 
indeed,  it  is  generated;  lastly,  the  papillae  become  capped  with  tooth 
substance  or  dentine. 

With  the  passage  of  the  teeth  through  the  gums  the  saccular  stage 
terminates,  and  the  third  or  eruptive  stage  is  entered  upon. 

The  second  or  permanent  teeth  pass  through  stages  precisely  sim- 
ilar to  those  of  the  first  or  milk  teeth,  the  papillae  and  follicles  being 
developed  in  crescent-shaped  depressions  placed  in  the  posterior  walls 
of  the  follicles  of  the  milk  teeth,  and  which  together  constitute  the 
secondary  dentinal  groove.* 

Having  now  obtained  a  general  idea  of  the  development  of  the 

*  For  further  particulars  relating  to  the  general  development  of  the  teeth,  consult 
the  admirable  paper  of  Mr.  Goodsir,  contained  in  the  Edinburgh  Medical  and  Sur- 
gical Journal.  From  the  researches  of  that  gentleman  we  learn  that  the  papillee  of 
the  teeth  appear  in  the  upper  jaw  before  the  lower;  that  those  of  the  milk  teeth  are 
developed  in  three  distinct  divisions — a  molar,  a  canine,  and  an  incisor;  that  the  molar 
is  the  first  formed,  the  canine  the  second,  and  the  incisor  the  third;  also,  that  the  first 
molar  is  developed  before  the  second,  and  the  first  incisor  before  the  second.  In  the 
permanent  teeth  the  papillse,  with  the  exception  of  the  anterior  molar,  appear  at  the 
mesial  line  first,  and  proceed  backwards. 


TEETH.  341 

teeth,  we  shall  be  prepared  to  understand  the  mode  of  development  of 
the  individual  tissues  of  the  teeth,  a  subject  which  has  been  studied 
more  particularly  by  Mr.  Nasmyth,  Professor  Owen,  and  Mr.  Tomes. 

Formation  of  the  Dentine. — It  would  appear  to  be  a  universal  law 
of  development,  that  all  animal  and  vegetable  tissues  should  take  their 
origin  in  cells;  of  this  law  the  teeth  present  a  striking  and  beautiful 
example. 

Thus,  the  dentine  is  formed  out  of  the  cells  placed  on  the  formative 
surface  of  the  papilla  or  dentine  pulp.  This  view  of  the  formation  of 
the  dentine  originated  with  Mr.  Nasmyth,*  and  its  accuracy  has  been 
confirmed  by  the  investigations  of  subsequent  writers,  and  especially 
by  those  of  Professor  Owen  and  Mr.  Tomes. 

Mr.  Owen,  in  his  work,  "Odontography,"  describes  with  great 
minuteness  the  several  steps  of  the  conversion  of  the  cells  of  the  pulp 
into  dentine,  and  also  enters  upon  the  consideration  of  the  develop- 
ment of  the  other  tissues  of  the  teeth. 

According  to  Mr.  Owen,  the  cells  of  the  pulp,  which  are  larger  and 
more  numerous  on  the  surface,  become  arranged  in  lines  which  are 
placed  vertical  to  that  surface;  subsequent  to  this  arrangement,  the 
nuclei  are  seen  to  divide,  first  longitudinally  into  two  portions,  each 
of  which  becomes  a  perfect  cell,  also  provided  with  a  nucleus;  these 
again  divide,  but  in  a  contrary  direction,  viz :  transversely ;  thus,  four 
secondary  cells  are  formed  within  the  cavity  of  the  primary  cell,  and 
out  of  its  single  nucleus.  The  number  is  not,  however,  limited  to 
four,  but  each  nucleus  may  give  origin  to  many  secondary  cells.  The 
primary  cells  are  placed  end  to  end,  as  are  also  the  secondary  cells; 
these  last  elongate  considerably,  until  at  length  they  coalesce,  thus 
forming  the  tubes  of  the  dentine ;  the  primary  cells  remaining  as  such, 
and  in  some  adult  human  teeth  being  faintly  visible.  The  primary 
and  secondary  cells,  however,  although  placed  end  to  end,  do  not 
form  straight  lines,  but  describe  greater  and  lesser  curves,  the  greater 
being  formed  by  the  primary  cells,  and  the  lesser  by  the  secondary; 
these  are  the  curvatures  to  which  reference  has  been  made  in  the 
description  of  the  tubes  of  the  dentine. 

The  views  of  Mr.  Tomes,f  although  not  essentially  at  variance  with 
those  of  Professor  Owen,  yet  differ  from  them  in  some  important  par- 
ticulars.   Mr.  Tomes  describes  the  primary  cells  themselves  as  dividing 

*"  Memoir  on  the  Development  and  Organization  of  the  Dental  Tissues,"  by  Alex- 
ander Nasmyth,  August,  1 836. 
t  Medical  Gazette,  Lecture  V. 


342  THE     SOLIDS. 

longitudinally  into  two  or  more  secondary  cells,  but  not  transversely ; 
subsequent  to  this  division,  each  cell  elongates,  and  at  length  unites 
with  those  above  and  below  it ;  thus  forming  the  dentinal  tubes.  Some- 
times two  cells  unite  with  but  a  single  cell  placed  beneath  it,  and  it  is 
in  this  way  that  the  branches  of  the  dentinal  tubes  are  produced, 
Thus,  according  to  Mr.  Tomes,  the  wall  of  the  primary  cell,  as  well 
as  its  nucleus,  enters  into  the  formation  of  the  dentinal  tubuli ;  while, 
according  to  Professor  Owen,  the  nuclei  alone  give  rise  to  these  tubes, 
the  walls  of  the  parent  cells  not  undergoing  elongation,  but  remaining 
to  constitute  a  considerable  portion  of  the  inter-tubular  tissue. 

In  the  human  tooth  I  have  been  unable  to  detect  the  existence  of 
the  primary  cells  of  the  dentine. 

Covering  the  dentine  pulp,  a  thin  transparent  membrane  exists; 
this,  on  its  outer  surface,  is  marked  with  numerous  hexagonal  depres- 
sions, into  which  the  enamel  fibres  are  received. 

Formation  of  the  Enamel. — Reference  has  been  made  to  a  blastemic 
matter,  consisting  of  nucleated  cells  imbedded  in  a  granular  matrix, 
and  situated  between  the  dentine  pulp  and  the  inner  surface  of  the 
sac  of  the  tooth;  this  is  the  enamel  pulp. 

The  cells  of  which  this  is  formed  are  larger  than  those  of  the  den- 
tinal pulp,  more  transparent,  and  with  nuclei  which  are  less  distinct; 
they  adhere  to  the  inner  surface  of  this  sac,  which  is  formed  of  a  pro- 
cess of  the  mucous  membrane  of  the  mouth  itself,  and  from  which, 
indeed,  they  are  evolved. 

This  membrane,  like  all  mucous  membranes,  consists  of  two  layers, 
an  outer  basement  of  fibrous  and  vascular  layer,  and  an  inner  colour- 
less and  blastemic  layer;  and  it  is  from  this  last  that  the  enamel  cells 
proceed.  It  is  marked  with  depressions  similar  to  those  existing  on 
the  surface  of  the  membrane  of  the  dentinal  pulp,  and  into  which  the 
terminations  of  the  fibres  of  the  enamel  are  received. 

It  is  out  of  the  cells  just  described  that  the  enamel  fibres  are  formed, 
and  this  in  a  manner  almost  similar  to  that  in  which  the  tubes  of  the 
dentine  are  themselves  developed;  thus  the  cells  are  first  arranged  in 
vertical  lines ;  these  commence  in  the  depressions  on  the  inner  sur- 
face of  the  tooth  sac,  and  proceed  from  without  inwards.  The  cells 
next  elongate  until  they  touch  each  other  by  either  short  or  oblique 
surfaces;  some  of  them  coalesce  by  their  extremities,  and  thus  form 
fibres  in  which  earthy  matter  is  deposited,  and  which  at  length  ter- 
minate in  the  hexagonal  depressions  situated  on  the  outer  surface  of 
the  membrane  of  the  pulp  of  the  dentine. 


TEETH 


313 


The  nuclei  elongate  with  the  cells,  and  either  disappear  altogether, 
or  else  remain  as  minute  cavities  running  down  the  centre. 

At  first  the  union  between  the  fibres  is  but  slight,  so  that  in  newly- 
formed  enamel  they  may  be  easily  separated  from  each  other  when 
placed  in  water,  to  which  they  will  impart  a  whitish  appearance,  in 
consequence  of  their  separation  and  diffusion  through  the  fluid. 

According  to  Mr.  Tomes,  also,  numerous  spaces  exist  between  the 
fibres  in  newly-formed  enamel;  and  it  is  owing  to  the  presence  of 
these  that  young  enamel  owes  its  opacity  and  brittleness. 

We  thus  perceive  that  the  enamel  is  to  be  regarded  rather  as  a 
modification  of  the  epithelium  than  of  bone. 

The  development  of  both  dentine  and  enamel  may  be  well  studied 
upon  the  teeth  of  young  pigs,  or  kittens,  at  the  birth. 

Formation  of  Cementum. — The  cementum  pulp  is  formed  between 
the  external  surface  of  the  dentine  and  the  internal  of  the  sac  of  the 
tooth,  it  being  intimately  united  to  both. 

It  consists,  like  the  pulps  of  the  other  tissues  of  the  teeth,  of  nucle- 
ated cells  imbedded  in  a  granular  matrix:  these  cells  are  described 
by  Mr.  Tomes*  as  resembling  those  of  temporary  cartilage,  being  oval 
in  shape,  and  having  their  long  axes  placed  transversely,  and  at  right 
angles,  to  the  length  of  the  tooth. 

The  cells  nearest  the  surface  of  the  dentine  are  the  first  to  become 
ossified;  and  when  their  ossification  and  development  is  completed, 
they  form  the  stellate  or  bone  cells  of  the  cementum.  Some  consider 
that  the  nuclei  of  these  cells  alone  give  origin  to  the  bone  cells,  and 
appearances  may  be  observed,  even  in  adult  cementum,  which  are 
favourable  to  this  opinion. 

The  cementum  is  often  seen  to  be  traversed  by  fibres  derived  from 
the  outer  layer  of  the  membrane  of  the  tooth-sac,  as  well  as  by  tubes 
prolonged  into  it  from  the  dentine. 

Notice  has  already  been  taken  of  the  small  hexagonal  cells  con- 
tained in  the  cementum,  and  situated  principally  upon  the  outer  surface 
of  the  dentine,  and  a  doubt  was  expressed  whether  these  were  to  be 
regarded  as  forming  a  part  of  the  structure  of  the  cementum,  or 
whether  they  constituted  a  distinct  organization. 

The  cementum  is  particularly  liable  to  an  increased  and  abnormal 
development  constituting  exostosis. 

It  would  thus  appear,  on  the  one  hand,  that  the  cementum  and 
dentine  are  but  modifications  of  each  other,  and  also  of  one  and  the 

*  See  Lecture  V. 


344  THE     SOLIDS. 

same  tissue,  the  osseous;  while,  on  the  other,  it  is  evident  that  the 
enamel  is  a  modification  of  the  epithelium. 

Mr.  Nasmyth  describes  the  cementum  as  passing  over  the  crown 
of  the  tooth  and  surface  of  the  enamel,  in  a  thin  layer  composed  of 
hexagonal  cells  and  fibres;  this  layer  exists  only  on  the  surface  of 
the  enamel  of  the  young  teeth  of  the  human  subject,  and  it  is  not 
composed  of  dentine,  but  consists  of  either  a  few  of  the  unelongated 
cells  of  the  enamel  pulp,  or,  as  Mr.  Tomes  considers,  of  the  inner 
surface  of  the  sac  of  the  tooth. 

Nature  of  Caries  of  the  Teeth. 

Various  opinions  have  been  entertained  in  reference  to  the  nature 
of  the  peculiar  decay  denominated  caries,  to  which  the  teeth  are 
so  liable.  Some  have  supposed  that  it  is  a  vital  process  resulting 
from  inflammation.  The  fact  that  dead  teeth,  that  is,  teeth  which 
have  been  removed  from  the  jaw  and  are  again  employed  as  artificial 
teeth,  undergo  a  similar  decay  to  that  which  affects  the  living  teeth, 
proves  that  it  is  not  essentially  a  vital  action,  although  it  cannot  be 
questioned  but  that  the  condition  of  vitality  and  the  state  of  develop- 
ment of  the  teeth  must  exert  a  powerful  influence  over  the  progress 
of  the  decay.  Other  observers  regard  the  decay  of  the  teeth  as  a 
purely  chemical  phenomenon,  the  earthy  matter  of  the  teeth  being 
removed  by  the  action  of  free  acid  in  the  saliva:  this  view  of  its 
nature  certainly  explains  many  of  the  circumstances  connected  with 
dental  caries,  and  is  supported  by  the  fact  already  cited,  viz:  that 
dead  teeth  are  susceptible  of  the  change. 

Two  facts,  however,  require  to  be  determined  before  the  chemical 
theory  of  the  decay  of  the  teeth  can  be  considered  to  be  proved ; 
first,  that  the  saliva  is  in  every  case  of  dental  caries  really  acid;  and 
second,  that  the  portion  of  the  tooth  which  is  subject  to  the  carious 
action  is  really  dead :  upon  both  of  these  points  considerable  doubts 
may  be  entertained. 

For  myself,  I  have  long  entertained  the  idea  that  the  real  and  proxi- 
mate cause  of  the  decay  of  the  teeth  was  to  be  found  in  the  presence 
of  some  parasitical  production,  and  that  the  condition  of  vitality  of 
the  teeth  and  of  the  states  of  the  saliva  were  to  be  considered  merely 
as  predisposing  causes  to  the  affection. 

This  idea  acquires  some  confirmation  from  an  examination  of  the 
carious  matter  of  a  tooth;  in  it  vast  quantities  of  minute  threads  or 
filaments,  possibly  those  of  a  fungus,  are  invariably  to  be  discerned, 


TEETH.  345 

as  well  as  numberless  dark  granules  and  irregular  masses,  bearing  in 
some  cases  the  aspect  of  true  cells. 

The  question  may  be  asked,  are  these  threads,  granules,  and  cell- 
like masses  any  thing  more  than  the  decomposing  elements  of  the 
dentine,  in  which  tissue  it  is  that  the  chief  ravages  of  the  decay 
occur  ?  The  answer  is,  possibly  not ;  but  the  surprising  numbers  of 
these  filaments  and  the  testimony  of  Mr.  Tomes  are  opposed  to  the 
idea  that  they  are  the  remains  of  the  tubes  of  the  dentine.  Mr.  Tomes 
thus  writes  in  his  tenth  Lecture  in  reference  to  the  tubes  of  the 
dentine :  "  A  transverse  section  of  carious  dentine,  rendered  soft  like 
cartilage  from  the  loss  of  its  lime,  presents  a  cribriform  appearance. 
The  tubuli  seem  enlarged  and  rather  irregular,  quite  unlike  the  figure 
they  present  in  healthy  dentine :  this  would  indicate  that  the  solvent 
enters  and  acts  upon  the  parietes  of  the  tubes  previous  to  affecting 
the  inter-tubular  tissue,  and  that  the  parietes  of  the  tubes  are  there- 
fore the  first  to  disappear.  I  feel  quite  certain  that  in  the  cases  I 
have  examined,  and  they  are  numerous,  the  parietes  of  the  tubuli,  so 
distinguishable  in  healthy  dentine,  have  almost,  if  not  wholly,  disap- 
peared with  the  removal  of  the  lime." 

Nature  of  Tartar  on  the  Teeth. 

Tartar  of  the  teeth  consists  of  phosphate  of  lime  mixed  up  with 
the  mucus  of  the  mouth  and  epithelial  scales:  it  contains  also  occa- 
sionally animalcules  and  vegetable  growths,  which  find  in  the  animal 
matter  of  the  tartar  a  convenient  nidus  for  their  development.  The 
accumulation  of  tartar  around  the  necks  of  the  teeth  results  from  an 
opposite  condition  of  the  saliva  to  that  to  which  chemists  ascribe 
dental  caries,  viz:  an  alkaline  state  of  it. 


TEETH. 

[The  substance  of  the  teeth  being  harder  than  that  of  bone,  thin  sections, 
which  should  be  made  in  different  directions,  must  be  first  cut  by  means  of 
a  lapidary's  wheel  charged  with  emery  or  diamond-dust.  These  sections 
are  then  farther  reduced  in  the  same  manner  as  those  of  bone — first,  by  the 
files,  next  by  the  hones,  and  lastly  polished.  Like  bone,  they  may  be 
either  mounted  in  balsam  or  dry ;  the  latter  method  is.  preferable  when  the 
section  is  sufficiently  thin  to  show  well  the  structure.] 


34G 


THE     SOLIDS. 


ART.   XVII.  — CELLULAR   OR    FIBROUS   TISSUE. 

The  truth  of  the  scientific  dictum,  that  every  living  thing  proceeds 
from  a  germ  or  ovum,  is  now  generally  admitted,  and  so  also  it  may 
be  said  that  each  portion  of  the  fabric  of  such  living  entity  takes  its 
origin  in  a  cell,  the  early  and  embryonic  condition  of  every  organ 
and  structure  being  reducible  to  that  of  a  cell. 

It  was  not,  however,  this  consideration  that  induced  the  older 
anatomists  to  apply  the  term  cellular  to  the  tissue  about  to  be 
described,  they  having  but  little  knowledge  of  the  structure  of  the 
elementary  cell,  or  of  its  universal  presence. 

They  were  led  to  denominate  the  tissue,  into  the  description  of 
which  we  are  about  to  enter,  cellular,  in  consequence  of  observing 
the  areolae  or  spaces  left  between  the  fibres  of  which  it  is  composed, 
and  which  they  erroneously  considered  to  be  cells.  The  cellular 
tissue,  then,  though  like  all  other  tissues,  taking  its  origin  in  cells, 
inasmuch  as  in  its  fully  developed  state  it  consists  of  fibres,  would  be 
more  accurately  denominated  the  fibrous  tissue,  as  indeed  by  many 
modern  anatomists  it  really  is :  the  term  cellular  tissue  is,  however, 
one  of  so  ancient  a  date,  and  one,  moreover,  in  such  general  use,  and 
so  well  understood,  that  it  seems  to  be  scarcely  advisable  to  abandon 
the  use  of  it  altogether. 

The  cellular  or  fibrous  tissue,  however,  as  ordinarily  encountered, 
is  constituted  not  of  a  single  description  of  fibre,  but  consists  of  two 
kinds  intermingled  in  different  proportions,  and  each  of  which  is 
possessed  of  distinct  characters  and  properties. 

The  most  remarkable  difference  between  the  two  descriptions  of 
fibrous  tissue  is,  that  the  one  is  white  and  inelastic,  and  the  other 
yellow  and  elastic :  each  of  these  will  be  described  under  different 
heads,  and  the  former  before  the  latter. 

INELASTIC    OR    WHITE    CELLULAR    OR    FIBROUS    TISSUE. 

Tendons,  Ligaments,  Membranes,  fyc. 

The  inelastic  fibrous  tissue  is  very  generally  distributed  throughout 
the  body:  it  constitutes  the  principal  portion  of  tendons,  ligaments, 
and  fasciae :  of  the  fibrous  membranes,  the  dura  mater,  pericardium, 


CELLULAR     OR     FIBROUS     TISSUE.  347 

periosteum,  perichondrium,  tunica  albuginea  of  the  testicle,  and 
sclerotic  coat  of  the  eye;  also,  of  the  serous,  synovial  and  mucous 
membranes,  as  well  as  of  the  skin,  and  it  forms  likewise  the  principal 
constituent  of  the  loose  cellular  tissue  which  is  so  abundantly  devel- 
oped throughout  every  tissue  and  organ  of  the  body,  but  which  is 
invariably  present  in  large  quantities  wherever  motion  is  necessary, 
as  in  the  axilla,  between  the  fasciculi  of  muscles,  and  in  the  course 
of  the  vessels. 

When  endowed  with  a  distinct  form,  as  in  the  case  of  the  tendons, 
it  may  be  called  morphous  inelastic  cellular  tissue,  and  when  it  has 
no  circumscribed  shape,  the  term  amorphous  may  be  applied  to  it: 
when  constituting  membrane,  it  exists  in  the  state  of  condensed 
fibrous  tissue  ;  and  when  it  merely  binds  organs  together,  or  allows  of 
the  motion  of  parts,  it  maybe  called  loose  or  reticular  cellular  tissue. 

There  is,  however,  a  form  of  the  inelastic  fibrous  tissue  which 
requires  not  merely  a  separate  name,  but  a  distinct  notice.  This 
form  is  met  with  in  the  great  omentum,  and  consists  in  the  fact  of 
spaces  of  irregular  size  and  form  being  left  between  the  fibres,  and 
hence  it  may  be  termed  areolar  cellular  tissue.  The  best  examples 
of  it  are  met  with  in  the  omenta  of  children  and  lean  persons,  which 
contain  but  little  fat.     (See  Plate  XL.  fig.  4.) 

The  inelastic  cellular  tissue  is  made  up  of  innumerable  unbranched 
threads  or  fibres  of  equal  calibre,  of  great  tenuity,  which  appear 
white  to  the  unassisted  sight,  but  of  a  yellow  colour  when  viewed 
under  the  microscope,  and  which  have  a  great  disposition  to  assume 
a  waved  or  zigzag  arrangement,  the  folds  formed  being  comparable 
to  those  in  which  a  loose  skein  of  silk  is  often  observed  to  fall.  (See 
Plate  XXXIX.  fig.  6.) 

When  dried,  the  inelastic  cellular  tissue  assumes  the  transparent 
appearance  and  consistence  of  horn;  in  water,  the  fibres  swell  up 
somewhat,  become  opaque  and  white,  but  still  preserve  their  form : 
in  acetic  acid,  they  swell  up  greatly,  become  indefinable,  soft  and 
gelatinous:  the  addition  of  a  mineral  acid  will,  however,  bring  the 
fibres  again  into  view.  A 

The  remarkable  effect  of  acetic  acid  on  the  inelastic  fibrous  tissue, 
has  suggested  the  idea  to  Mr.  Bowman  that  "it  is  rather  a  mass  with 
longitudinal  parallel  streaks  (many  of  which  are  creasings),  and  which 
has  a  tendency  to  slit  up  almost  ad  infinitum  in  the  longitudinal 
direction." 

There  are  several  considerations  which  may  be  urged  in  disproof 


348  THE     SOLIDS. 

of  this  view;  the  first  is,  the  mode  of  development  belonging  to  this 
tissue ;  the  second,  the  fact  that  the  fibres  are  all  of  nearly  an  equal 
diameter;  and  the  third  is,  that  the  tissue  still  retains  its  fibrous 
constitution  even  after  the  application  of  acetic  acid. 

The  white  fibrous  tissue  is  employed  wherever  a  strong  and 
inelastic  material  occupying  but  little  space  is  required. 

A  degree  of  elasticity  not  unfrequently  appears  to  belong  to  this 
tissue;  but  this  is  rather  apparent  than  real,  and  depends  upon  the 
extent  of  its  admixture  with  the  next  form  of  fibrous  or  cellular 
tissue  to  be  described,  viz:  the  elastic.     (Plate  XXXIX.  jig.  1) 

ELASTIC    CELLULAR    OR    FIBROUS    TISSUE. 

The  elastic  cellular  or  yellow  fibrous  tissue  is  distinguished  from 
the  inelastic  form  by  its  branched  filaments,  the  diameter  of  which  is 
unequal,  its  elasticity,  its  deeper  colour,  and  the  absence  of  any 
appreciable  effect  on  the  addition  of  acetic  acid.    (See  Plate  XL.  jig.  1.) 

Like  the  inelastic  fibrous  tissue,  it  rarely  occurs  in  an  unmixed 
form,  being  mostly  intermingled  with  it  in  variable  proportions :  thus, 
it  is  encountered  in  tendons,  ligaments,  and,  indeed,  in  all  forms  and 
conditions  of  the  inelastic  cellular  tissue;  it  constitutes  the  principal 
portion  of  the  ligamenta  sub-flava  and  nuchas,  of  the  transverse  fascia 
of  the  abdomen,  of  the  crico-thyroid  and  thyro-hyoid  membranes,  of 
the  chordae  vocales,  of  the  internal  lateral  ligament  of  the  lower  jaw, 
of  the  stylo-hyoid  ligaments,  of  the  middle  coat  of  the  arteries,  and 
of  the  membrane  uniting  the  rings  of  the  trachea  and  its  ramifications. 
It  is  also  met  with  in  considerable  quantities  beneath  the  mucous 
membrane  of  the  oesophagus,  at  the  base  of  the  epiglottis,  in  main- 
taining which  in  the  erect  position  it  is  probably  mainly  instrumental, 
in  the  lungs  and  in  the  integuments  of  the  penis. 

The  elastic  cellular  tissue  presents  some  differences  of  appearance 
and  structure,  in  certain  of  the  situations  in  which  it  is  encountered : 
thus,  in  the  tendons  and  in  the  smaller  blood-vessels  (Plate  XL.  jigs. 
1,  2,  3.  5)  the  fibres  are  very  slender,  appear  to  be  but  little  branched, 
and  contain  at  intervals  nuclei  in  the  same  manner  as  do  the  fibres 
of  unstriped  muscles;  in  the  reticular  cellular  tissue  again,  they  are 
slender,  unbranched,  and  without  nuclei  (see  Plate  XXXIX.  jig.  7) ; 
in  the  ligamenta  flava  and  nucha?,  in  the  crico-thyroid  and  thyro-hyoid 
membranes,  the  fibres  are  thick,  much  branched,  curled,  and  inter- 
woven, but  they  do  not  present  nuclei  (see  Plate  XL.  jig.  1) ;  in  the 
larger  arteries,  the  fibres  are  slender,  and  are  united  together  so  as  to 


CELLULAR      OR      FIBROUS     TISSUE.  3 19 

form  areolae  (see  Plate  XL.  fig.  2),  while  in  the  smaller  blood-vessels 
they  are  distinctly  nucleated,  as  already  observed. 

There  is  little  doubt  but  that  the  several  forms  of  elastic  tissue  just 
described  do  really  represent  different  stages  and  states  of  the  same 
structure ;  and  it  will  be  observed,  that  some  of  them,  and  especially 
that  of  the  small  blood-vessels,  approach  very  closely  in  structure 
and  appearance  to  that  of  unstriped  muscular  fibre :  the  fibres  of  the 
former  differ,  however,  in  being  sparingly  branched,  and  in  their 
more  slender  diameter. 

It  is  not  easy,  without  the  addition  of  reagents,  to  distinguish  the 
two  forms  of  fibrous  or  cellular  tissue  from  each  other  when  mixed 
together:  nevertheless,  when  the  two  are  well  separated,  the  elastic 
fibres  may  be  frequently  singled  out  from  the  inelastic,  in  consequence 
of  their  presenting  a  darker  and  stronger  outline,  as  well  as  of  their 
following  a  more  curled  and  tortuous  course.  (See  Plate  XXXIX. 
fig.  7.)  Acetic  acid  applied  to  a  portion  of  mixed  cellular  tissue,  at 
once  allows  the  elastic  fibres  to  be  clearly  seen,  rendering  the  inelastic 
fibres  transparent,  and  almost  invisible. 

There  are  several  parts  of  the  human  organization  described  by 
modern  minute  anatomists  and  physiologists  as  being  in  part  com- 
posed of  unstriped  muscular  fibre;  these  are  the  skin,  dartos,  nipple, 
clitoris,  penis,  the  ducts  of  the  larger  glands,  as  the  ductus  communis 
choledochus,  the  ureters,  and  vasa  deferentia.  Now,  I  find  that  all 
these  parts,  which  I  have  examined  with  care,  owe  their  contractility, 
and  their  power  of  erection,  to  the  presence  of  the  nucleated  form  of 
the  elastic  tissue  which  has  been  described  as  existing  in  tendons  and 
the  smaller  blood-vessels,  and  not  to  any  form  of  muscular  fibre;  and 
further,  that  in  the  majority  of  them,  and  especially  in  the  dartos, 
penis,  clitoris,  and  nipple,  this  elastic  tissue  is  confined  almost  entirely 
to  the  blood-vessels,  the  walls  of  which  it  constitutes :  this  fact  may 
be  readily  ascertained  in  the  instance  of  the  dartos  by  taking  a  small 
fragment  of  that  membrane  when  in  a  fresh  condition,  and  having 
spread  it  out  on  the  surface  of  a  piece  of  glass  without  the  addition 
of  any  fluid,  then  submitting  it  to  the  microscope,  when  the  number, 
size,  and  course  of  the  blood-vessels  may  be  traced,  and  the  disposition 
of  the  intervening  fibrous  inelastic  tissue  recognised:  in  the  recent 
state,  however,  the  vessels  are  filled  with  blood,  the  presence  of  which 
prevents  the  satisfactory  detection  of  the  elastic  constituent  of  the 
blood-vessels :  if  now,  however,  acetic  acid  be  applied  to  the  fragment 
of  membrane  thus  spread  out,  the  inelastic  fibrous  tissue  will  become 


350  THE     SOLIDS. 

indistinct,  the  red  blood  corpuscles  contained  in  the  vessels  will  be 
dissolved,  and  the  tissue  of  the  blood-vessels  clearly  brought  out. 
(Plate  XLIII.  fig.  3.) 

The  extent  of  contraction  of  which  the  dartos  is  susceptible  is  very- 
great,  and  the  act  of  contraction  must  of  course  exert  a  very  powerful 
influence  over  the  circulation  of  the  blood  in  its  vessels.  In  the 
contracted  state  of  this  membrane,  the  slender  fibres  of  the  elastic 
tissue,  as  well  as  their  nuclei,  are  frequently  curled  up  in  a  spiral 
manner,  an  arrangement  by  which  any  amount  of  shortening  may  be 
secured. 

The  contraction  of  the  tissue  of  the  dartos,  and  indeed  of  all  elastic 
tissue,  is  evidently  not  a  physical,  but  a  vital  act:  this  is  shown  by 
the  relaxation  and  contraction  which  it  experiences  in  sympathy 
with  the  condition  of  the  vital  powers,  as  well  as  with  any  causes,  as 
heat  and  cold,  which  affect  these  powers. 

The  corpora  cavernosa  penis  and  corpos  spongiosum  urethrae  are 
almost  entirely  composed  of  blood-vessels,  and  the  peculiarity  of 
these  parts  consists  in  the  large  size  of  the  vessels,  and  in  their 
repeated  inosculation.     (Plate  XLIII.  j%.  4.) 

In  the  lungs,  the  blood-vessels  are  so  numerous,  that  they,  in  this 
case,  also  constitute  the  principal  portion  of  the  fabric  of  these 
organs: — this  may  be  beautifully  seen  in  the  lungs  of  the  lower 
reptiles,  as  the  triton  and  frog. 

Henle  has  described  a  peculiar  arrangement  of  the  fibres  of  elastic 
tissue.  "I  have  already  said,"  he  remarks,  "that  the  fibres  of  the 
cellular  tissue  are  for  the  most  part  united  into  a  number  more  or  less 
considerable,  and  thus  form  flattened  bands  of  different  thickness. 
These  bands  unite  in  their  turn  to  produce  others  larger,  or  even 
membranes,  and  thus,  sometimes  they  apply  themselves  parallelly  to 
each  other  ;  at  others,  they  cross  each  other  in  the  most  varied 
directions.  When  the  cellular  tissue  fills  the  interstices  of  organs 
under  the  form  of  a  soft  mass,  easy  to  displace,  and  extensible,  the 
bundles  may  be  perceived  without  the  least  preparation,  seeing  that 
they  cross  and  interlace  in  all  directions,  and  that  even  to  the  naked 
eye,  they  represent  a  net-work  of  delicate  fibres.  The  size  of  the 
bundles,  which  I  call  primitive  bundles,  or  after  their  origin,  the 
fibres  of  the  cells  of  cellular  tissue  vary  from  the  0'003  to  the  0  006 
of  a  line.  The  majority  of  the  primitive  bundles  are  deprived  of 
special  envelope:  the  fibres  may  easily  be  detached,  the  one  from  the 
other,  and  separate,  when  one  bends  a  bundle  strongly.     But  in  many 


CELLULAR     OR     FIBROUS     TISSUE.  351 

situations  they  are  interlaced,  and  held  together  by  filaments,  which 
differ  from  the  fibres  of  cellular  tissue  by  their  chemical  and  micro- 
scopical peculiarities,  while  in  certain  respects  they  approach  the 
fibres  of  elastic  tissue;  of  which  we  shall  give  a  description  further  on. 
They  are  almost  still  finer  than  the  fibres  of  cellular  tissue,  quite  flat 
and  homogeneous,  but  with  outlines  much  more  obscure,  and  they  are 
distinguished,  above  all,  by  the  considerable  folds,  which  they  describe 
when  they  are  in  a  state  of  separation.  In  order  to  recognise  them, 
it  is  necessary  to  place  the  cellular  tissue  in  contact  with  acetic  acid : 
in  this  acid  the  bundles  of  cellular  tissue  become  transparent,  swell, 
and  cease  to  appear  fibrous,  while  the  filaments  which  envelope  them 
undergo  no  change.  In  this  manner  it  happens  that  a  bundle,  which 
appears  to  be  composed  of  the  ordinary  interlaced  fibres  of  cellular 
tissue,  comports  itself  after  having  been  treated  with  acetic  acid,  as  a 
transparent  cylinder  divided  by  contractions  often  very  regular,  and 
which  one  soon  observes  to  be  caused  by  a  filament  which  runs 
spirally  around  the  bundle;  or  also  by  separated  rings  placed  at  a 
greater  or  less  distance  from  each  other  I  have  rarely  succeeded  in 
reducing  the  turns  to  a  single  filament,  and  I  am  obliged  in  conse- 
quence to  leave  undecided  the  question,  whether  it  does  not  sometimes 
happen  that  many  filaments  are  rolled  spirally  around  a  bundle.  The 
formations  which  I  have  described  show  themselves  in  no  part  in  a 
more  beautiful  manner  than  in  the  delicate  and  firm  cellular  tissue, 
which  is  situated  at  the  base  of  the  brain  beneath  the  arachnoid, 
between  the  vascular  trunks  and  the  nerves,  and  which  becomes 
distended  into  isolated  filaments,  on  extension,  as,  for  example,  in  any 
part  of  the  circle  of  Willis.  There  I  have  never  sought  the  spiral 
filaments  in  vain;  nevertheless,  analogous  bundles,  encircled  with 
spirals,  may  be  seen  also  upon  other  parts  of  the  economy,  in  serous 
membranes,  in  the  sub-cutaneous  cellular  tissue,  in  the  skin,  and  even 
in  the  tendons."* 

It  appears  to  me  that  Henle  has  misunderstood  the  structure,  and 
consequently  the  nature  of  the  formations  noticed  by  him:  there  can 
A  be  little  doubt  but  that  these,  in  place  of  being  bundles  of  filaments 
composed  of  inelastic  fibrous  tissue  encfrcled  with  a  spiral  coil  of 
elastic  tissue,  are  in  reality  hollow  cylinders,  vessels  in  fact  in  progress 
of  formation,  consisting  of,  in  the  stage  described  by  the  German 
physiologist,  an  inner  transparent  and  apparently  structureless  tunic, 
enclosed  in  a  coil  of  elastic  fibrous  tissue. 

*  Anal.  Gen.  vol.  i.  pp.  377,  378. 


352  THE      SOLIDS. 

The  correctness  of  this  view  is  established  by  the  very  convincing 
fact,  that  the  tubular  formation  in  the  condition  just  described  may 
be  traced  up  to  the  state  of  perfect  blood-vessels,  some  of  which  may 
also  now  and  then  be  seen  dividing  into  branches,  and  containing, 
moreover,  blood  corpuscles.  Several  of  the  stages  of  the  development 
of  these  vessels  are  seen  in  Plate  XL.fig.  3. 

DEVELOPMENT    OF   CELLULAR    TISSUE. 

Exact  observations  are  still  required  on  the  subject  of  the  develop- 
ment of  both  the  elastic  and  the  inelastic  forms  of  the  cellular  or 
fibrous  tissue,  and  especially  of  that  of  the  latter  form.  Schwann  and 
all  other  observers  after  him  have  described  the  cellular  tissue  as 
taking  its  origin  in  cells  of  an  elongated  form,  from  the  extremities  of 
which  fibres,  mostly  branched,  proceed,  the  cells  themselves  ultimately 
becoming  absorbed :  microscopists,  however,  have  not  as  yet  attempted 
to  point  out  the  differences  which  doubtless  exist  in  the  development 
of  the  two  forms  of  cellular  tissue,  but  have  for  the  most  part  con- 
tented themselves  with  the  above  general  description. 

It  appears  to  me  that  the  observations  already  made  on  the  devel- 
opment of  the  cellular  tissue  apply  only  to  the  yellow  or  elastic  kind ; 
and  to  this  conclusion  I  am  led  by  the  fact  that  observers  describe 
the  elongated  nuclei  as  giving  origin  to  branched  filaments;  and  we 
know  that  the  fibres  of  the  inelastic  fibrous  tissue  are  simple,  and  not 
branched. 

According  to  my  observations,  both  forms  of  cellular  tissue  origin- 
ate in  cells. 

The  cells  of  the  white  fibrous  tissue  exist  first  as  rounded  nuclei, 
around  which  the  cell  wall  gradually  makes  its  appearance,  and  these 
cells  when  fully  formed  are  large,  granular,  elongated,  fusiform,  and 
from  each  extremity  at  length  proceeds  a  single  unbranched  thread, 
which  gradually  becomes  extended  into  a  filament  or  fibre,  which  is 
produced  by  the  growth  and  extension  of  the  cell  wall  itself,  and  the 
extremity  of  which  unites  for  the  production  of  an  elongated  thread 
with  that  proceeding  from  the  other  cells  placed  above  and  below  it : 
finally,  the  process  terminates  by  the  absorption  of  the  nuclei.  (See 
Plate  XLIII.jffe.  2.) 

The  cells  of  the  yellow  fibrous  tissue  also  exist,  at 'first  as  nuclei, 
then  as  fusiform  cells,  but.  differ  from  those  of  the  white  fibrous  tissue 
in  the  subsequent  steps  of  their  development,  in  that  the  cells  are  dis- 
posed in  lines,  each  fibre  being  formed,  as  is  the  case  with  the  unstriped 


DEVELOPMENT     OF     CELLULAR     TISSUE.  353 

muscular  fibre,  by  the  union  of  the  filaments,  proceeding  from  each 
series  of  linearly  disposed  cells,  and  in  that  the  filaments  proceeding 
from  the  cells  are  very  frequently  branched.  (See  Plate  XXXIX.  figs 
1,  2.    Plate  XL.  figs.  3.  5.) 

The  above-described  mode  of  development  may  be  followed  out  in 
longitudinal  and  cross  sections  of  tendon  treated  with  acetic  acid;  also, 
in  the  smaller  vessels  of  the  pia  mater,  and  in  those  placed  in  the 
mixed  cellular  tissue  which  separates  the  different  striped  muscular 
fasciculi:  we  thus  perceive,  that  in  the  case  of  the  yellow  fibrous 
tissue,  many  nuclei  are  required  to  form  a  single  filament ;  and  further, 
that  there  is  a  strong  analogy  in  the  mode  of  its  development  with 
that  of  muscular  fibre,  as  also  in  the  physical  properties  of  the  two 
tissues. 

In  the  fibrillation  of  the  fibrin  of  the  blood  we  have  an  example  of 
the  formation  of  filaments  independently  of  any  development  from 
cells,  and  at  one  time  I  conceived  that  the  fibres  of  the  white  fibrous 
tissue  might  possibly  originate  in  a  similar  manner. 

23 


354  THE     SOLIDS. 


ART.    XVIII.  —  MUSCLE. 

Few  of  the  animal  tissues  have  been  more  extensively  examined 
than  the  muscular:  the  multiplied  observations  made  on  its  structure 
have,  however,  led  neither  to  that  uniformity  of  opinion  respecting  it, 
nor,  indeed,  to  that  accurate  knowledge  of  its  minute  anatomy,  which 
might  have  been  anticipated;  of  the  truth  of  this  position,  evidence 
will  be  shortly  adduced. 

Muscles  admit  of  division  into  the  voluntary,  or  those  which  are 
under  the  control  of  the  will,  and  the  involuntary,  or  those  of  which 
the  action  takes  place  independently  of  the  will;  the  former  consist 
of  the  muscles  of  animal  life — those,  for  example,  of  locomotion — and 
the  latter  embrace  those  of  organic  life,  as  the  muscles  of  the  aliment- 
ary canal  (the  sphincters  of  the  oesophagus  and  anus  excepted,  which 
are  to  a  certain  extent  voluntary),  the  heart,  the  uterus,  the  bladder,  &c. 

It  will  be  observed,  that  the  involuntary  muscles,  or  those  of 
organic  life,  usually  encircle  the  hollow  viscera;  there  are  some  other 
situations,  however,  in  which  involuntary  muscular  fibres  are  met 
with,  as  in  the  trachea  and  its  bronchial  ramifications,  the  iris,  the 
sarcolemma,  and,  according  to  some  observers,  as  Bowman,  they  are 
also  encountered  in  the  dartos  and  covering  the  excretory  ducts  of 
the  larger  glands,  as  the  ductus  communis  choledochus,  the  ureters, 
and  vasa  deferentia;  and  it  is  with  them  a  matter  of  question  how 
far  the  contractility  of  the  skin,  and  the  erection  of  the  penis,  clitoris 
and  nipple,  may  be  dependent  upon  the  presence  of  involuntary  mus- 
cular fibrillae.  In  the  preceding  article  I  have,  however,  shown  that 
the  contractility  of  these  parts  depends  upon  the  presence  of  a  nucle- 
ated form  of  elastic  tissue,  allied  to  unstriped  muscular  fibre  in  many 
of  its  properties,  but  yet  distinct  therefrom. 

Corresponding  with  the  division  of  muscles  into  voluntary  and  invol- 
untary, there  exist  differences  of  structure:  thus,  the  muscles  under 
the  control  of  the  will  are  all  striped,  while  those  which  are  not  under 
its  influence  are  unstriped.  To  this  rule,  however,  one  remarkable 
exception  may  be  mentioned,  viz:  the  muscles  of  the  heart,  the  action 
of  which  is  to  a  great  extent  involuntary,  and  which  are  yet  striped : 
this  exception  is  rather  apparent  than  real,  as  will  be  seen  hereafter. 


MUSCLE.  355 


STRUCTURE    OF     MUSCLE. 

A  striped  muscle  is  made  up  of  a  number  of  unbranched  fibres,  each 
of  which  is  included  in  a  distinct  sheath,  the  sarcolemma,  and  consists 
of  a  number  of  threads  or  fibrillae :  the  fibres  again  are  collected  into 
sets  or  bundles  called  lacerti;  these  are  held  together,  and  yet  separ- 
ated by  a  mixed  form  of  cellular  tissue,  which  also  contains  fat  vesicles, 
blood-vessels  and  nerves. 

An  unstriped  muscle  consists  of  fibrillae,  intermingled  with  fibrous 
tissue:  these  do  not  form  fibres,  and  consequently  there  is  no 
sarcolemma. 

Between  striped  and  unstriped  muscle  there  is  no  essential  or  spe- 
cific structural  difference:  the  one  is  not  to  be  regarded  as  typically 
distinct  from  the  other,  but  both  should  rather  be  considered  as  differ- 
ent conditions  in  the  development  of  one  and  the  same  tissue.  Of 
this  position,  evidence  will  be  hereafter  adduced. 

According  to  the  above  view,  muscular  fibre  presents  two  grand 
stages  of  development;  the  first  of  which  is  represented  by  the 
unstriped  fibrilla,  and  the  second  by  the  striped  muscular  fibre. 

We  shall  first  describe  the  structure  of  the  unstriped  muscular 
fibrilla,  because  it  represents  an  earlier  condition  of  development  than 
the  striped. 

Structure  of  Unstriped  Muscular  Fibrillce. — Unstriped  muscles 
consist  of  fibrillae  which  are  unbranched,  rather  broad,  somewhat  flat, 
and  which  contain,  imbedded  in  their  substance,  elongated  and  gran- 
ular nuclei.     (See  Plate  X.hl.  fig.  2.) 

The  fibrillae  usually  run  parallel  to  each  other,  and  form  thin  layers 
and  fasciculi,  which  are  separated  from  each  other  by  cellular  tissue, 
and  frequently  interlace. 

The  nuclei  are  sometimes  imbedded  in  the  substance  of  the  fibrillae, 
without  at  the  same  time  increasing  their  diameter:  at  others,  they 
render  the  fibrillae  ventricose  from  their  great  size ;  and  again,  in  other 
cases,  they  protrude  from  their  sides.  (See  Plate  Uhl.fig.  2.)  They 
are  best  seen  after  the  addition  of  acetic  acid. 

Unstriped  muscles  are  doubtless  freely  supplied  with  blood-vessels 
and  with  nerves. 

The  unstriped  muscle  is  called  into  action  with  greater  difficulty 
than  the  striped;  its  action  is  also  slower,  and  of  a  peculiar  kind,  giv- 
ing rise  to  the  vermicular  and  peristaltic  motion,  seen  especially  in 
the  intestines. 


356  THE     SOLIDS. 

This  slower  and  less  energetic  action  results  from  its  lower  degree 
of  organization. 

The  muscular  structure  of  the  heart,  the  action  of  which  is  to  a 
considerable  extent  involuntary,  requires  a  special  description.  The 
muscular  tissue  of  this  organ  has  been  usually  supposed  to  constitute 
an  exception  in  its  structure  to  that  of  other  involuntary  muscles,  and 
that  while  it  performed  the  office  of  an  involuntary  muscle,  it  yet 
possessed  the  structure  of  a  voluntary  muscle,  its  fibres  being  striped. 

Mr.  Bowman,  one  of  the  very  best  authorities  on  the  structure  of 
the  muscular  fibre,  gives  the  following  description  of  the  tissue  of  the 
heart :  "  The  cross  stripes  on  the  fibres  of  the  heart  are  not  usually 
so  regular  or  distinct  as  in  those  of  the  voluntary  muscles.  They  are 
often  interrupted,  or  even  not  visible  at  all.  In  some  of  the  lower 
animals  their  sarcous  elements  never  form  transverse  stripes.  These 
fibres  are  usually  smaller  than  the  average  diameter  of  those  of  the 
voluntary  muscles  of  the  same  subject  by  two-thirds,  as  stated  by  Mr. 
Skey."* 

This  description  is  very  imperfect,  and  in  some  respects,  according 
to  my  observations,  incorrect.  Thus,  the  muscular  substance  of  the 
heart  does  not  form  fibres  at  all,  but  consists  simply  of  fibrillae,  which 
agree  in  every  respect  with  those  of  other  involuntary  muscles,  save 
in  their  transverse  striation:  thus  they  have  the  same  considerable 
diameter:  they  are,  in  like  manner,  abundantly  nucleated  (see  Plate 
XLI.  fig.  3),  and  they  have  the  same  arrangement,  interlacing  with 
each  other,  and  not  forming  fibres  included  in  a  sarcolemma,  as  is  the 
case  with  the  voluntary  muscular  tissue.  The  transverse  striae,  too, 
have  not  the  deep  and  permanent  character  belonging  to  the  fibrillas 
of  ordinary  striped  muscle,  as  is  evinced  by  the  fact  that  acetic  acid 
effaces  all  vestige  of  striation. 

It  thus  appears  that  the  muscles  of  the  heart  agree  in  structure 
much  more  closely  with  that  of  other  involuntary  muscles,  which  is 
contrary  to  what  is  generally  supposed,  than  they  do  with  that  of  the 
voluntary  muscles. 

Thus,  then,  the  structure  and  the  function  of  the  muscles  of  the 
heart  are  in  accordance,  and  not  in  antagonism,  as  is  usually  con- 
ceived, the  single  point  of  difference  between  its  fibrillae  and  those  of 
other  involuntary  muscles  consisting  in  the  feeble  transverse  striation, 
the  presence  of  which  evinces  a  somewhat  higher  degree  of  develop- 
ment, as  well  as  a  greater  power  of  contractility. 

*  Physiological  Anatomy,  p.  161. 


MUSCLE 


357 


St 'ructure  of  Striped  Muscular  Fibre. — The  striped  muscle  consists 
of  fibres:  each  of  these  is  included  in  a  distinct  envelope,  termed 
Sarcolemma,  and  is  made  up  of  a  number  of  lesser  fibres  or  fibrillae. 
(See  Plate  XLII.  fig.  1.) 

The  fibres  vary  very  considerably  in  size,  not  merely  in  different 
animals,  but  also  according  to  the  age  of  an  animal,  and  even  in  a 
single  bundle  of  the  same  animal,  some  of  them  being  three  or  four 
times  larger  than  others,  and  the  smaller  being  usually  adherent  to 
the  larger  fibres;  a  fact  which  has  reference  to  the  development  of 
muscular  tissue,  and  which  will  be  explained  when  we  arrive  at  the 
consideration  of  that  portion  of  our  subject.  (See  Plate  XLII.  fig  A) 
The  difference  in  the  size  of  the  fibres  according  to  age  is  very 
remarkable,  those  of  the  foetus  being  several  times  smaller  than  the 
fibres  of  the  adult.     (See  Plate  XLIL  fig.  1,  and  Plate  XLIII.  fig.  1.) 

They  differ  also  to  a  very  considerable  extent  in  form  as  well  as 
magnitude:  thus,  in  a  cross-section  and  in  a  recent  state,  they  are 
seen  to  be  more  or  less  angular  and  compressed,  but  still  preserving, 
in  most  cases,  much  of  the  character  of  cylinders.  In  the  dry  con- 
dition, this  angularity  is  greatly  increased,  and  to  this  state  of  the 
fibres  the  representations  hitherto  given  chiefly  refer.  (See  Plate 
XLII.  fig.  5.) 

The  fibres,  both  great  and  small,  are,  as  already  observed,  arranged 
in  bundles  or  lacerti,  of  variable  size;  those  of  the  same  bundle  run 
parallel  to  each  other,  and  the  different  bundles  are  separated,  and  yet 
held  together  by  mixed  fibrous  tissue. 

Examined  with  a  moderate  power  of  the  microscope,  each  fibre 
is  seen  to  exhibit  numerous  transverse  striae,  which  are  placed  at 
tolerably  regular  distances  from  each  other:  some  fibres,  also,  and 
especially  such  as  have  been  preserved  in  spirit,  present  numerous 
fainter  longitudinal  striae. 

When  viewed  with  a  somewhat  higher  object-glass,  and  when  each 
fibre  has  been  torn  into  pieces  by  needles,  its  entire  bulk  will  be  seen 
to  be  made  up  of  a  number  of  slender  threads  of  equal  diameter, 
which  present  a  distinct  transverse  striation. 

It  was  formerly  very  generally  supposed  that  the  transverse  lines 
on  the  striped  muscular  fibre  were  produced  by  a  filament  which 
wound  spirally  around  it :  this  notion  is,  doubtless,  erroneous,  as 
indeed  it  is  now  generally  allowed  to  be. 

It  has  been  observed,  that  the  fibrillae  are  themselves  marked  with 
transverse  striae :  now,  it  is  not  difficult  to  convince  one's  self  that  the 


358  THE     SOLIDS. 

striation  of  the  fibre  is  produced  by  the  striae  of  the  fibrillar,  the  striae 
of  one  fibrilla  corresponding  with  that  of  another,  and  thus  giving  rise 
to  a  line  which  extends  entirely  across  the  diameter  of  the  fibre. 

The  correctness  of  this  explanation  might  have  been  easily  inferred 
from  a  knowledge  of  the  composition  of  the  striated  muscular  fibre 
of  banded  fibrillae,  and  from  the  aspect  of  the  transverse  line  itself, 
which,  when  examined  with  a  high  power  of  the  microscope,  does 
not  present  the  appearance  of  an  uninterrupted  and  continuous  line, 
such  as  would  be  produced  by  the  winding  of  a  filament  around  it, 
but  rather  of  a  line  formed  by  the  apposition  of  a  series  of  dots  or 
shorter  lines ;  in  which  manner,  indeed,  it  is  that  the  striation  of  the 
fibre  is  really  produced,  as  we  have  seen. 

The  fibrillae  contained  in  each  fibre  are  unbranched,  of  great 
tenuity,  of  nearly  equal  diameter  (see  Plate  XLII.  fig.  1),  and  their 
number  varies  greatly,  amounting  in  the  larger  fibres  to  as  many  as 
fifty  or  sixty,  while  in  the  smaller  they  may  not  exceed  from  one  to 
five  and  upwards,  according  to  the  breadth  of  the  filament. 

The  striae  present  a  very  uniform  and  strongly  marked  character: 
the  spaces  between  them  are  not,  however,  equal:  thus,  they  are 
sometimes  rather  longer  than  the  diameter  of  the  fibrilla:  at  other 
times,  they  are  shorter,  and  when  the  striae  are  very  close,  the  fibrilla 
becomes  ventricose  or  moniliform. 

Much  difference  of  opinion  prevails  as  to  the  nature  of  the  striation 
exhibited  by  the  fibrillae.  Drs.  Sharpey*  and  Carpenterf  incline  to 
the  opinion  that  each  fibrilla  consists  of  a  series  of  particles  or  cells 
cohering  in  linear  series,  and  that  the  lines  indicate  the  point  of 
junction  of  these ;  Mr.  Erasmus  WilsonJ  attributes  a  still  more 
complicated  structure  to  the  striated  fibrilla.  He  believes  that  two 
kinds  of  cells  exist  in  each  fibrilla;  a  pair  of  light  cells,  separated  by 
a  delicate  line,  being  interposed  between  each  pair  of  dark  ones. 

Lastly,  Bowman  considers  that  the  lines  indicate  the  divisions 
between  particles,  which  he  denominates  "sarcous  elements." 

My  own  view  of  the  nature  of  these  lines  differs  from  that  of  all 
the  gentlemen  named.  I  consider  that  the  lines  in  question  are 
produced  by  the  simple  corrugation  or  wrinkling  of  the  threads  at 
regular  distances :  a  view,  the  accuracy  of  which  is  all  but  proved 
by  a  consideration  of  the  development  of  muscular  fibre,  and  by  the 

*  Quain's  Anatomy,  5th  edition,  vol.  ii.  p.  168. 

f  Human  Physiology,  p.  176. 

\  Manual  of  Anatomy,  3d  edition,  p.  16. 


MUSCLE.  350 

action  of  acetic  acid  on  the  fibrillar  of  the  heart,  the  transverse 
markings  of  which  it  entirely  obliterates. 

The  fibrillae  are,  as  already  stated,  included  in  a  sheath,  the  sarco- 
lemma  of  Bowman,  both  together  constituting  the  fibre.  The  sheath 
cannot  at  all  times  be  seen:  it  may,  however,  frequently  be  so,  and 
especially  when  the  fibrillae  have  been  torn  across,  the  sheath  at  the 
same  time  not  having  been  divided,  its  greater  elasticity  enabling  it 
to  resist  the  force  which  was  sufficient  to  rupture  the  muscular 
fibrillae.  It  is  in  such  cases  that  the  best  view  of  this  membrane  is 
obtained.     (See  Plate  XLU.  fig.  1.) 

Treated  with  acetic  acid,  each  fibre  discloses  most  distinctly  a 
considerable  number  of  elongated  and  granular  nuclei,  the  outlines 
of  which  are  in  some  cases  visible,  even  without  the  application  of 
the  acid.     (See  Plate  XLII.  fig.  2.) 

Of  these  nuclei,  Mr.  Bowman  remarks:  "In  the  fully-formed  fibre, 
if  it  be  large,  they  lie  at  various  depths  within  it;  but  if  small,  they 
are  at  or  near  the  surface.  They  are  oval  and  flat,  and  of  so  little 
substance,  that  though  many  times  larger  than  the  sarcous  elements, 
and  lying  among  them,  they  do  not  interfere  with  their  mutual  apposi- 
tion and  union."  "It  is  doubtful  whether  the  identical  corpuscles, 
originally  present,  remain  through  life,  or  whether  successive  crops 
advance  and  decay  during  the  progress  of  growth  and  nutrition:  but 
it  is  certain  that  as  development  proceeds,  fresh  corpuscles  are  depos- 
ited, since  their  absolute  number  is  far  greater  in  the  adult  than  in 
the  foetus,  while  their  number  relatively  to  the  bulk  of  the  fibre  at 
these  two  epochs  remains  nearly  the  same."* 

The  above  description  is  in  part  only  correct.  Thus  I  find,  first, 
that  the  nuclei  are  invariably  situated  on  the  external  surface  of  the 
fibre,  the  majority  within  the  sheath,  and  either  adherent  to  this,  or  to 
the  exterior  fibrillae,  some  also  being  placed  on  the  outer  surface  of 
the  sarcolemma;  facts  which  throw  much  light  upon  the  development 
of  the  muscular  fibre;  secondly,  that  the  nuclei  are  not  usually  free 
nuclei,  but  are  contained  in  most  cases  in  filaments  in  every  way 
similar  to  those  of  unstriped  muscle,  and  with  which  they  are  identical. 

Were  the  nuclei  really  scattered  throughout  the  substance  of  a 
muscular  fibre,  they  would  infallibly  destroy  the  parallelism  of  the 
striae,  and  greatly  interfere  with  its  contractile  power. 

The  interpretation  to  be  given  of  the  location  of  the  nuclei  and 
fibres  of  unstriped  muscle  in  the  situations  indicated,  will  be  explained 

*  Physiological  Anatomy,  vol.  i.  pp.  158, 159. 


360 


THE     SOLIDS. 


when  the  subject  of  the  development  of  muscular  fibre  is  considered ; 
at  the  same  time,  also,  the  point  raised  by  Mr.  Bowman,  as  to  the 
persistence  of  the  nuclei,  will  be.  discussed. 

The  fibres  of  the  upper  part  of  the  oesophagus  are  striped,  while  those 
of  the  lower  half  are  unstriped.  It  has  been  considered  a  matter  of 
uncertainty  whether  the  two  pass  by  insensible  gradations  of  structure 
into  each  other,  or  whether  they  terminate  abruptly.  I  believe,  after 
careful  examination,  that  the  latter  supposition  is  the  correct  one. 

With  a  few  remarks  upon  the  peculiar  views  entertained  by  Mr. 
Bowman,  in  reference  to  the  structure  of  the  striated  muscular  fibre, 
the  discussion  of  the  structure  of  muscle  may  be  brought  to  a 
conclusion. 

"It  was  customary,"  writes  Mr.  Bowman,*  "both  before  and  since 
his  time  (the  time  of  Fontana),  as  at  the  present  day,  to  regard  the 
fibre  as  a  bundle  of  smaller  ones,  whence  the  term  primitive  fasci- 
culus, first  given  to  it  by  him,  and  adopted  by  Muller;  but  this  view 
of  the  subject  is  imperfect.-'  The  fibre  always  presents,  upon  and 
within  it,  longitudinal  dark  lines,  along  which  it  will  generally  split 
up  into  fibrillae ;  but  it  is  by  a  fracture  alone  that  such  fibrillae  are 
obtained.  They  do  not  exist  as  such  in  the  fibre.  And  further,  it 
occasionally  happens  that  no  disposition  whatever  is  shown  to  the 
longitudinal  cleavage;  but  that,  on  the  contrary,  violence  causes  a 
separation  along  the  transverse  dark  lines,  which  always  intersect  the 
fibre  in  a  plane  perpendicular  to  its  axis.  By  such  cleavage,  discs, 
and  not  fibrillae,  are  obtained,  and  this  cleavage  is  just  as  natural, 
though  less  frequent,  than  the  former.  Hence,  it  is  as  proper  to  say 
that  the  fibre  is  a  pile  of  discs,  as  that  it  is  a  bundle  of  fibrillae :  but,  in 
fact,  it  is  neither  the  one  nor  the  other,  but  a  mass  in  whose  structure 
there  is  an  intimation  of  the  existence  of  both,  and  a  tendency  to 
cleave  in  the  two  directions.  If  there  was  a  general  disintegration 
along  all  the  lines  in  both  directions,  there  would  result  a  series  of 
particles,  which  may  be  termed  primitive  particles,  or  sarcous 
elements,  the  union  of  which  constitutes  the  mass  of  the  fibre. 
These  elementary  particles  are  arranged  and  united  together  in 
two  directions.  All  the  resulting  discs,  as  well  as  fibrillae,  are  equal 
to  one  another  in  size,  and  contain  an  equal  number  of  particles. 
The  same  particles  compose  both.  To  detach  an  entire  fibrilla,  is  to 
abstract  a  particle  of  every  disc,  and  vice  versa.     The  width  of  the 

*  Physiological  Anatomy,  vol.  i.  pp.  151, 152. 


MUSCLE.  361 

fibre  is  therefore  uniform,  and  is  equal  to  the  diameter  of  any  one  of 
its  fibrillae,  and  is  liable  to  the  greatest  variety." 

This  view  of  the  structure  of  the.  striated  muscular  fibre  is  inge- 
niously conceived  and  well  expressed;  nevertheless,  it  can  be  shown, 
I  think,  notwithstanding  its  ingenuity,  to  be  incorrect. 

There  are  two  considerations  which  appear  to  me  to  be  sufficient 
to  disprove  the  view  just  propounded.  The  first  is,  that  the  rudi- 
mentary muscular  fibre  consists  of  one  or  more  threads  or  fibrillae, 
containing  imbedded  in  them  a  number  of  elongated  nuclei,  which, 
however,  have  no  correspondence  with  the  transverse  markings ;  and 
the  second  is,  that,  while  any  muscular  fibre  may  at  any  time  be 
readily  separated  into  its  component  fibrillae,  the  simultaneous  trans- 
verse cleavage  spoken  of  and  figured  by  Mr.  Bowman  is  an  occurrence 
of  extreme  rarity,  and  one,  moreover,  of  which  I  have  never  been  able 
to  perceive  the  slightest  trace  in  any  muscular  fibre  which  has  fallen 
under  my  notice. 

It  would  thus  appear  that  the  older  view  is  the  correct  one,  and 
that  the  striped  muscular  fibre  is  made  up,  as  already  described,  of  a 
variable  number  of  fibrillae  enclosed  in  a  tubular  sheath.* 

Blood  Vessels  of  Muscles. — Muscles  are  copiously  supplied  with 
blood-vessels;  the  larger  vessels  are  contained  in  the  cellular  tissue 
separating  the  fascicles  or  lacerti  of  the  muscles,  and  which  serves  to 
support  and  to  conduct  them ;  the  smaller  vessels  or  capillaries  are 
not  encircled  by  cellular  tissue,  but  penetrate  between  the  fibres, 
forming  numerous  capillary  loops  and  meshes,  having  their  long  axes 
disposed  in  the  direction  of  the  length  of  the  fibres.  This  arrange- 
ment of  the  capillaries  is  shown  in  Plate  XLI.  fig.  4. 

Much  of  the  colour  of  a  muscle  arises  from  the  blood  enclosed  in 
the  vessels,  but  not  all,  a  portion  of  it  being  contained  in  the  muscular 
fibres  themselves. 

It  is  evident  that  the  contraction  of  the  fibres  exercises  much 
influence  upon  the  capillary  circulation,  reducing  the  calibre  of  the 
capillaries  to  such  an  extent  as  that  the  blood-corpuscles  can  pass 
through  them  only  in  an  elongated  form. 

In  the  course  of  the  larger  vessels,  imbedded  in  the  inter-fascicular 
cellular  tissue,  fat  corpuscles  are  often  abundantly  distributed,  as 
represented  in  Plate  XLI.  fig.  1 . 

Nerves  of  Muscles. — Muscles  are  also  abundantly  supplied  with 
nerves,  principally  those  of  locomotion.     Burdach  has  figured  and 

*  See  Appendix,  page  548. 


362  THE     SOLIDS. 

described  the  nerves  in  muscles  as  forming  loops,  which  either  join 
other  neighbouring  loops  or  else  return  into  themselves.  The  figure 
and  description  given  by  Burdach  have  been  adopted  by  almost  all 
succeeding  anatomists ;  notwithstanding  which,  I  would  observe,  that 
I  have  never  seen  the  nerves  terminating  in  muscle  in  the  manner 
indicated;  not,  however,  that  I  doubt  the  fact  of  their  doing  so, 
because  such  a  mode  of  termination  is  common  to  nerves;  but  would 
simply  infer  from  this,  that  the  loop-like  arrangement  is  neither  very 
general  nor  very  obvious. 

According,  then,  to  the  latest  physiologists,  nerves,  strictly  speaking, 
really  have  no  termination  whatever  in  muscles :  an  opinion,  the 
accuracy  of  which  is  more  than  doubtful. 

I  find  that  the  nerves,  after  branching  in  a  dichotomous  manner, 
have  a  real  termination,  and  that  from  time  to  time  certain  tubules 
leave  the  main  trunks,  and  end  in  the  formation  of  elongated  and 
ganglioniform  organs  situated  between  the  fibres  of  muscle.  (See 
Plate  XLLJig.  4.) 

UNION    OF    MUSCLE    WITH    TENDON. 

The  unstriped  muscular  fibrilla  is  rarely,  if  ever,  attached  to  tendon 
or  aponeurosis  :  the  striped  fibre,  on  the  contrary,  is  almost  con- 
stantly so. 

Two  errors  have  prevailed  in  reference  to  the  union  of  the  striated 
muscular  fibre  with  tendon. 

The  first  has  reference  to  the  form  of  the  extremity  of  the  fibre  in 
connexion  with  the  tendon;  the  second  to  the  precise  mode  of  junc- 
tion between  the  two. 

Thus,  most  observers  have  described  and  figured  the  fibre  as 
terminating  in  a  conical  point,  from  which  the  fibres  of  the  fibrous 
tissue  of  the  tendon  proceed  in  a  straight  line. 

This  description  is  contrary  to  fact,  both  as  respects  the  form  of 
the  fibre  and  its  mode  of  union  with  the  tendon:  muscular  fibre  is 
rarely,  if  ever,  inserted  vertically  into  a  tendon  or  aponeurosis ;  but  in 
all  the  instances  which  have  fallen  under  my  observation,  the  insertion 
has  been  either  oblique  or  occasionally  at  right  angles  with  the  tendon; 
the  extremity  of  the  fibre  being  in  the  one  case  also  oblique,  and  in 
the  other  truncate :  this  termination  is  the  very  opposite  of  that 
usually  attributed  to  it.  Let  us  next  see  in  what  way  the  two  struc- 
tures are  united.  In  no  one  instance  have  I  ever  seen  the  fibres  of 
the  fibrous  tissue  of  the  tendon  unite  themselves  directly  with  the 
muscular  fibre :  on  the  contrary,  the  mode  of  junction  has  always 


MUSCLE.  3G3 

been  effected  in  the  following  manner: — the  sheath  of  each  fibre  is 
prolonged  upon  the  surface  of  the  tendon  where  the  union  is  oblique, 
and  certain  of  the  fibres  of  the  tendon  are  extended  upon  and  inter- 
lace with  the  terminal  portions  of  the  muscular  fibres  and  their 
investing  sheaths.     (See  Plate  XLII.  fig.  4.) 

MUSCULAR    CONTRACTION. 

Many  attempts  have  been  made  to  determine  the  exact  changes 
which  the  muscular  fibre  undergoes  in  its  passage  to  a  state  of  con- 
traction; these  attempts  do  not  appear  to  me  to  be  altogether  satis- 
factory and  successful. 

The  earliest  opinion  formed,  in  reference  to  muscular  contraction, 
supposed  that  during  contraction  the  fibres  and  fibrillae  of  muscle  are 
disposed  in  a  zigzag  manner,  such  a  disposition  of  the  fibres  of  course 
having  the  effect  of  materially  shortening  the  muscle.     (Plate  XLIII. 

fig-  5.) 

The  advocates  of  this  view  seem  to  have  overlooked  the  fact  that 
fibres  thus  disposed,  having  no  fixed  or  direct  points  from  which  to 
act,  would  have  their  power  by  such  an  arrangement  rather  diminished 
than  increased:  this  idea  has  therefore  been  justly  discarded,  and  an 
account  of  the  nature  of  muscular  contraction,  much  more  closely 
approximating  to  the  truth,  substituted  in  its  place. 

Mr.  Bowman,  who  has  written  by  far  the  best  account  of  muscular 
contraction  which  has  yet  appeared,  discriminates  between  passive 
and  active  contraction  of  muscle :  the  former  he  conceives  to  be  a 
uniform  act,  involving  and  affecting  equally  the  entire  mass  of  the 
muscle :  the  latter,  on  the  other  hand,  he  considers  to  be  a  partial  act, 
implicating,  first,  a  particular  part  or  parts  of  a  fibre ;  subsequently 
leaving  these,  and  advancing  to  other  and  neighbouring  parts  of  the 
same  fibre. 

This  view  is  founded  principally  upon  the  experiment  detailed 
below,  made  upon  a  fibre  of  the  claw  of  a  crab,  which  still  retained 
its  contractility.  "In  an  elementary  fibre  from  the  claw,  laid  out  on 
glass,  and  then  covered  with  a  wet  lamina  of  mica,  the  following 
phenomena  are  always  to  be  observed:  The  ends  become  first  con- 
tracted and  fixed.  Then  contractions  commence  at  isolated  spots 
along  the  margin  of  the  fibre,  which  they  cause  to  bulge.  At  first 
they  only  engage  a  very  limited  amount  of  the  mass,  spreading  into 
its  interior  equally  in  all  directions,  and  being  marked  by  a  close 
approximation  of  the  transverse  stripes.      These  contractions  pull 


364  THE     SOLIDS. 

upon  the  remainder  of  the  fibre  only  in  the  direction  of  its  length; 
so  that  along  its  edge  the  transverse  stripes  in  the  intervals  are  very 
much  widened  and  distorted.  These  contractions  are  never  station- 
ary, but  oscillate  from  end  to  end,  relinquishing  on  the  one  hand  what 
they  gain  on  the  other.  When  they  are  numerous  along  the  same 
margin,  they  interfere  most  irregularly  with  one  another,  dragging 
one  another  as  though  striving  for  the  mastery,  the  larger  ones  con- 
tinually overcoming  the  smaller;  then  subsiding,  as  though  spent, 
stretched  by  new  spots  of  contraction ;  and  again,  after  a  short  period 
of  repose,  engaged  in  their  turn  by  some  advancing  wave.  This  is 
the  first  stage  of  the  phenomenon.  At  a  subsequent  stage,  the  ends 
of  the  fibre  commonly  cease  to  be  fixed,  in  consequence  of  the  inter- 
mediate portions,  by  their  contraction,  receiving  some  of  the  pressure 
of  the  glass.  The  contractions,  therefore,  increasing  in  number  and 
extent,  gradually  engage  the  whole  substance  of  the  fibre,  which  then 
is  reduced  to  at  least  one-third  of  its  original  length."* 

To  this  experiment,  which  I  have  never  been  able  successfully  to 
repeat,  some  exceptions  may  be  taken.  Thus,  it  is  known  that  water 
has  a  powerful  and  remarkable  effect  in  exciting  muscular  fibre  which 
still  retains  its  irritability  to  contraction,  and  the  nodulated  aspect  of 
the  fibre  mentioned,  may  have  been  due  to  the  fact  that  the  fibre  was 
not  entirely  immersed  in  water  (the  piece  of  mica  being  merely 
moistened),  but  only  touched  by  that  fluid  at  certain  intervals,  which 
most  probably  corresponded  with  the  bulgings  of  the  fibre  referred  to. 
This  explanation  is  supported  by  the  effect  of  water  on  recent  mus- 
cular fibre,  entirely  immersed  in  that  liquid.  Thus,  on  the  moment 
of  immersion,  the  fibres  contract  greatly  in  length,  increase  in  a 
corresponding  proportion  in  bulk,  become  irregularly  bulged  and 
nodulated:  the  transverse  lines  on  the  fibres  disappear,  the  longitu- 
dinal lines  at  the  same  time  becoming  more  strongly  marked  than 
usual.  (See  Plate  XLII.  jig.  3.)  These  several  effects  are  due  to 
the  extraordinary,  unequal,  and  doubtless,  also,  abnormal  contraction 
induced  by  the  stimulus  of  water.  Presuming,  therefore,  that  in  the 
experiment  referred  to,  the  phenomena  occur  in  the  order  described, 
yet  it  would  not  be  safe  to  adopt  the  conclusion,  from  this,  that  they 
represent  the  several  stages  of  the  normal  contraction  of  a  muscular 
fibre.  Again,  it  might  be  argued,  that  the  nodular  condition  described 
as  belonging  to  a  muscle  in  a  state  of  active  contraction  would  be 
most  unfavourable  for  the  full  exercise  of  the  power  of  contraction, 

*  Physiological  Anatomy,  pp.  180,181. 


MUSCLE.  365 

seeing  that  the  nodules  of  one  fibre  would  necessarily  interfere  with 
those  of  the  contiguous  fibres,  and  thus  impede  its  own  as  well  as 
their  contraction. 

For  the  above  reasons,  therefore,  I  would  place  but  little  reliance 
upon  the  experiment  quoted,  and  prefer  to  adopt  an  explanation  more 
simple  in  its  character,  and  yet  entirely  sufficient  to  explain  the 
condition  of  a  muscle  during  its  state  of  most  active  yet  entirely 
normal  contraction. 

I  conceive  that  no  distinct  line  of  demarcation  exists  whereby 
active  and  passive  muscular  contraction  can  be  discriminated:  the 
two  are  but  different  degrees  of  the  same  power,  and  manifest  them- 
selves by  phenomena  which  differ  not  in  kind,  but  simply  in  extent. 

If  a  muscle  of  the  leg  of  a  frog  be  isolated  from  its  fellows,  or  if 
the  tongue  of  the  same  animal  be  extended  and  pinned  to  the  margins 
of  an  aperture  made  in  a  piece  of  cork,  the  only  change  which  can  be 
observed  to  take  place  in  the  muscular  fibre,  when  stimulated  to  con- 
traction, consists  in  an  approximation  of  its  striae,  neither  waves  nor 
nodules  manifesting  themselves  in  its  course. 

Again;  immersion  of  muscular  fibre,  which  has  almost  lost  its  con- 
tractile power  in  water,  will  be  followed  by  an  approximation  of  the 
striae,  and  a  proportionate  increase  in  the  diameter  of  the  filament. 

Now,  the  approximation  of  the  striae  is  the  only  visible  sign  which  I 
have  ever  been  able  to  detect  in  natural  muscular  contraction ;  and  it  is 
amply  sufficient  to  account  for  the  shortening  and  increase  in  diameter 
which  a  muscle  undergoes  during  its  state  of  most  active  contraction. 

The  distance  between  the  striae  in  a  fibre  placed  somewhat  on  the 
stretch,  as  are  all  muscular  fibres  in  their  natural  state,  and  in  that 
which  is  in  a  state  of  contraction,  varies  greatly,  and  is  very  evident, 
the  striae  in  the  contracted  fibre  being  often  one-third  or  even  one- 
half  closer  together  than  they  are  in  the  fibre  in  its  ordinary  state 
of  tension.  The  approximation  of  the  striae  to  the  extent  just  men-' 
tioned,  presuming  the  entire  length  of  the  fibres  to  be  in  a  contracted 
condition,  would  reduce  the  length  of  the  muscle  in  the  same  pro- 
portion, viz:  to  the  extent  of  a  third  or  even  one-half. 

Muscular  contraction,  then,  I  would  define  to  be  a  simple  shorten- 
ing of  the  fibres  of  a  muscle,  accompanied  by  an  increase  in  their 
breadth ;  this  shortening  in  the  striped  muscular  fibre  being  evinced 
by  an  approximation  of  the  transverse  striae,  as  well  as  by  an  increase 
in  its  diameter,  while  in  the  unstriped  fibre  it  is  manifested  solely  by 
an  increase  in  the  thickness  of  the  fibrillae.     (Plate  XJAI.jig.  3.  a,  b.) 


306  THE     SOLIDS. 

Whether,  in  muscular  contraction,  the  whole  length  of  the  fibres 
of  a  muscle  is  engaged,  or  part  only  of  their  length,  or  whether,  during 
the  continuance  of  the  contraction  of  a  muscle,  its  fibres  remain  in  a 
state  of  quiescence ;  or  whether  they  undergo  an  alternate  contrac- 
tion and  relaxation,  in  obedience  to  the  interrupted  stimulus  derived 
through  the  medium  of  the  nerves,  it  is  not  easy  to  determine  with 
certainty;  nevertheless,  it  is  most  probable  that  where  the  contraction 
is  very  intense,  and  long  sustained,  such  an  alternation  of  condition 
does  exist. 

The  stiffening  of  the  body,  which  occurs  after  death,  known  by  the 
terms  "rigor  mortis,"  "cadaveric  rigidity,"  is  due  to  muscular  con- 
traction. This  rigidity  usually  comes  on  a  few  hours  after  death; 
and  after  continuing  for  a  variable  time,  not  exceeding  six  or  seven 
days,  again  disappears.  There  is  much  variety,  however,  in  the 
exact  periods  of  the  advent  and  departure  of  the  rigidity:  it  has  been 
observed  to  come  on  latest,  attain  its  greatest  intensity,  and  to  last 
longest  in  the  bodies  of  robust  persons,  who  have  either  died  of  short 
and  acute  diseases,  or  who  have  suffered  a  violent  death.  On  the 
contrary,  it  has  been  remarked  to  set  in  soonest,  and  to  disappear 
earliest,  in  persons  of  feeble  constitution,  and  those  who  have  died  of 
a  lingering  and  exhausting  malady. 

The'  immediate  cause  of  cadaveric  rigidity  has  never  yet  been 
satisfactorily  explained.  Some  have  supposed  that  it  depends  upon 
the  coagulation  of  the  blood  in  the  capillaries — an  hypothesis  scarcely 
tenable:  others,  with  more  reason,  conceive  that  it  proceeds  from 
the  solidification  of  the  fibrin  of  which  muscle  is  chiefly  constituted — 
that  it  is,  in  fact,  a  phenomenon  precisely  analogous  to  the  coagulation 
of  the  fibrin  of  the  blood. 

An  explanation  differing  from  both  of  the  former  has  suggested 
itself  to  my  mind.  I  conceive  that  muscular  contraction  may  possibly 
be  brought  about  by  the  stimulus  of  the  thinner  and  more  watery 
parts  of  the  blood,  &c,  acting  on  the  still  irritable  muscular  fibre, 
and  which  are  known  to  escape  from  their  containing  vessels  very 
shortly  after  the  extinction  of  life.  Of  this  passage  of  fluid  through 
the  walls  of  its  receptacle,  we  have  a  familiar  instance  in  the  case  of 
the  gall-bladder  and  its  contents. 

Two  other  points  require  to  be  briefly  alluded  to,  in  relation  to  the 
subject  of  muscular  contraction:  the  first  is  the  muscular  sound 
heard  on  applying  the  ear  to  a  muscle  in  action,  and  which  has  been 


MUSCLE.  3G7 

likened  by  Dr.  Wollaston*  to  the  distant  rumbling  of  carriage-wheels  ; 
the  second  relates  to  the  fact  made  known  by  MM.  Bequerel  and 
Breschet,  that  a  muscle  during  contraction  experiences  an  augment- 
ation of  the  temperature. 

DEVELOPMENT    OF    MUSCLE. 

The  muscular  tissue,  like  the  majority  of  those  which  have  hitherto 
been  described,  takes  its  origin  in  cells. 

The  term  fibre  is  applicable  only  to  the  striped  form  of  muscle,  in 
which  a  number  of  fibrillse  are  included  in  an  investing  sheath  common 
to  them;  these  striped  fibrillse  of  the  striped  fibre  of  voluntary  muscles, 
are  analogous  to  the  unstriped  fibrillse  of  the  involuntary  muscles. 

The  process  of  the  development  of  muscle  may  be  divided  into 
three  stages: 

In  the  first,  isolated  cells,  arranged  in  linear  series,  unite  to  form 
the  unstriped  fibrilla,  the  nuclei  remaining. 

This  stage  appertains  to  all  unstriped  muscular  fibre. 

In  the  second,  the  transverse  striee  or  markings  appear  upon  the 
fibrillse,  the  nuclei  still  remaining. 

This  stage  is  permanently  exemplified  in  the  muscles  of  the  heart, 
temporarily  in  the  voluntary  muscles  of  the  foetus,  and  probably  also 
in  some  few  other  muscles. 

In  the  third  period,  the  fibrillse  become  very  slender,  the  transverse 
markings  more  defined,  and  the  nuclei  altogether  disappear. 

This  condition  is  represented  in  all  the  fully-developed  striped 
muscles  of  animal  life. 

But  the  striped  voluntary  muscular  fibre,  even  of  the  adult,  con- 
stantly exhibits,  and  is  constantly  passing  through  the  three  stages 
just  described ;  a  fact  not  generally  known.  It  has  been  ascertained, 
indeed,  since  the  time  of  Valentin,  that  the  striped  muscular  fibre  of 
the  foetus  originates  in  cells,  and  also  that  cell  nuclei  are  contained 
in  each  fibre  of  the  adult ;  but  it  has  not  been  perceived  that  the 
fibrillse  also  proceed  from  cells,  and  that  the  stage  of  muscular  devel- 
opment, that  of  unstriped  muscular  fibre,  likewise  exists  in  the  volun- 
tary muscles  of  both  the  foetus  and  the  adult. 

It  has  been  supposed,  as  we  have  already  seen,  that  the  nuclei 
which  are  met  with  in  the  striped  muscular  fibre  are  scattered 
throughout  its  entire  thickness :  this  has  been  shown  to  be  erroneous, 
and  also  that  the  nuclei  are  situated  only  on  the  exterior  of  each  fibre. 

*  Phil.  Trans.  1811. 


368  THE     SOLIDS. 

Now,  in  every  adult  striped  muscular  fibre,  we  find  the  nuclei 
under  the  following  circumstances :  some  few  of  them  are  in  a  free 
state;  others,  more  numerous,  are  contained  in  fibrillae,  both  striped 
and  unstriped;  of  these  fibrillae,  the  majority  are  on  the  inside  of  the 
sarcolemma;  but  some  of  them  are  also  on  its  exterior,  adhering  to 
its  surface,  and  constituting  a  considerable  part  of  its  substance: 
lastly,  internal  to  these  nucleated  fibrillae,  other  fibrillae,  which  form 
the  chief  bulk  of  each  fibre,  exist  destitute  of  nuclei. 

With  a  good  defining  object-glass  many  of  these  unstriped  fibres 
may  be  traced  for  a  considerable  distance  along  the  fibre,  and  may 
be  observed  to  contain  as  many  as  twenty  nuclei.    . 

From  these  several  facts  it  would  thus  appear,  that  striped  and 
unstriped  muscular  fibre  do  not  represent  distinct  types  of  structure, 
but  that  each  is  to  be  regarded  as  a  different  stage  in  the  development 
of  the  same.  The  unstriped  muscular  fibrilla  passes  through  but  one 
stage  of  growth,  and  then  its  development  becomes  permanently 
arrested :  the  fibrillae  of  the  heart,  &c,  attain  a  higher  degree  of 
development,  the  nucleated  fibres  becoming  marked  with  transverse 
striae ;  after  which  their  growth  permanently  ceases :  lastly,  the 
striped  fibrillae  of  the  voluntary  muscles  reach  the  third  and  last 
period  in  the  development  of  the  muscular  tissue,  having  their  nuclei 
obliterated,  and  becoming  exceedingly  slender. 

It  would  appear,  also,  that  new  fibrillae  are  constantly  being  devel- 
oped, even  in  the  adult  muscular  fibre. 

But  certain  appearances  may  be  observed  which  render  it  extremely 
probable  that  not  merely  new  fibrillae  are  constantly  being  developed, 
but  also  that  new  fibres  are  continually  being  formed. 

Thus,  it  is  a  common  thing  to  meet  with  unstriped  and  even  striped 
fibrillae,  which  are  slightly  adherent  to  the  external  surface  of  the 
sarcolemma ;  again,  small  muscular  fibres  attached  to  the  larger 
fibres,  and  consisting  of  but  very  few  fibrillae,  may  constantly  be 
observed.     (Plate  XLII.  fig.  4.) 

In  the  uterus  we  have  a  very  remarkable  example  of  a  periodic 
development  and  subsequent  absorption  of  unstriped  muscular  fibrillae. 

The  last  point  to  which  reference  need  be  made  is,  to  the  doubt 
expressed  as  to  "whether  the  identical  corpuscles  originally  present" 
(in  the  fibre)  "remain  through  life,  or  whether  successive  crops 
advance  and  decay  during  the  progress  of  growth  and  nutrition."* 
This  matter  is  no  longer  doubtful :  the  particulars  observed  in  relation 

*  Loc.  eit,  pp.  182, 183. 


MUSCLE.  .}".) 

to  the  development  of  muscular  fibre  enable  us  to  give  a  solution  of 
the  difficult  v.  Thus,  there  is  no  question  but  that  successive  crops 
of  corpuscles  or  nuclei  are  continually  being  formed  in  both  the 
striped  and  the  unstriped  muscles,  and  that  those  in  the  former  are 
permanent,  while  in  the  latter  they  are  only  transitory. 

It  will  be  readily  perceived  that  the  above-detailed  views  of  the 
structure  and  development  of  the  muscular  fibre  differ,  in  very  many 
important  particulars,  from  those  generally  entertained.  According 
to  the  views  of  most  physiologists,  the  unstriped  muscular  fibre  is  the 
analogue  of  the  striped  fibre ;  while,  according  to  those  of  the  author, 
the  striped  fibrilla  is  the  analogue  of  the  unstriped  fibrilla,  or  "fibre" 
of  most  writers.  Dr.  Carpenter,  in  the  third  edition  of  the  '•'Princi- 
ples of  Human  Physiology,"  thus  clearly  gives  expression  to  the 
notion  that  the  striped  and  unstriped  muscular  fibres  are  the  analogues 
of  each  other.  "From  the  preceding  history,  it  appears  that  there 
is  no  difference  at  an  early  stage  of  development  between  the  striated 
and  the  non-striated  forms  of  muscular  fibre.  Both  are  simple  tubes, 
containing  a  granular  matter,  in  which  no  definite  arrangement  can 
be  traced,  and  presenting  enlargements  occasioned  by  the  presence 
of  the  nuclei.  But  while  the  striated  fibre  goes  on  in  its  develop- 
ment, until  the  fibrilla?,  with  their  alternation  of  light  and  dark  spaces, 
are  fully  produced,  the  non-striated  retains  throughout  life  its  original 
embryonic  character."  The  description  just  quoted,  in  its  application 
to  the  fibrillce  of  the  striped  and  unstriped  muscle,  would  be  most 
true,  but  in  its  comparison  of  the  unstriped  fibrillar  with  the  entire 
striped  fibre,  it  is  completely  at  fault. 

There  is  considerable  discrepancy  between  the  views  entertained 
by  Bowman  and  Valentin,  and  those  expressed  in  this  work,  in  relation 
to  the  development  of  muscle,  as  will  be  evident  from  the  statement  of 
them  by  the  former  gentleman.  "The  researches  of  Valentin  and 
Schwann  have  shown  that  a  muscle  consists,  in  the  earliest  stage,  of 
a  mass  of  nucleated  cells,  which  first  arrange  themselves  in  a  linear 
series,  with  more  or  less  regularity,  and  then  unite  to  constitute  the 
elementary  fibres.  As  this  process  of  the  union  of  the  cells  is  going 
forward,  a  deposit  of  contractile  material  gradually  takes  place  within 
them,  commencing  on  the  inner  surface,  and  advancing  towards  the 
centre,  till  the  whole  is  solidified.  The  deposition  occurs  in  granules, 
which,  as  they  come  into  view,  are  seen  to  be  disposed  in  the  utmost 
order,  according  to  the  two  directions  already  specified.  These 
granules  or  sarcous  elements  being  of  the  same  size  as  in  the  perfect 

24 


370  THE     SOLIDS. 

muscle,  the  transverse  stripes  resulting  from  their  opposition  are  of 
the  same  width  as  in  the  adult;  but  as  they  are  very  few  in  number, 
the  fibres  which  they  compose  are  of  corresponding  tenuity.  From 
the  very  first  moment  of  their  formation  these  granules  are  parts  of  a 
mass,  and  not  independent  of  one  another;  for,  as  soon  as  solid  matter 
is  deposited  in  the  cells,  faint  indications  of  a  regular  arrangement  in 
granules  are  usually  to  be  met  with.  It  is  common  for  the  longitudinal 
lines  to  become  well  defined  before  the  transverse  ones:  when  both 
are  become  strongly  marked,  as  is  always  the  case  at  birth,  the  nuclei 
of  the  cells,  which  were  before  visible,  disappear  from  view,  being 
shrouded  by  the  dark  shadows  caused  by  the  multitudinous  refractions 
of  the  light  transmitted  through  the  mass  of  granules ;  but  they  can 
still  be  shown  to  exist  in  the  perfect  fibre,  in  all  animals,  and  at  all 
periods  of  life,  by  immersion  in  a  weak  acid;  which,  while  it  swells 
the  fibrous  material  of  the  granules,  and  obliterates  their  intervening 
lines,  has  no  action  on  the  nuclei." 

According  to  the  views  entertained  by  the  author,  a  striated  mus- 
cular fibre,  in  the  earliest  period  of  its  development,  consists  of  cells 
arranged  in  linear  series :  these  unite  together,  giving  origin  to  the 
fibrilla  and  not  the  fibre,  and  that  each  fibrilla  of  a  fibre  is,  in  like 
manner,  developed  from  cells. 

Dr.  Sharpey,  in  the  fifth  edition  of  Quain's  "Anatomy,"  makes  the 
remark,  in  treating  of  the  subject  of  the  development  of  muscle,  "  But 
much  still  remains  to  be  explained  by  future  investigation."  The 
truth  of  this  remark  it  is  conceived  is,  in  some  degree,  exemplified  in 
the  foregoing  article  on  muscular  fibre. 


MUSCLE. 


371 


MUSCLE. 

[To  what  the  striation  of  muscular  fibre  is  owing,  is  not  yet  satisfactorily 
established.  The  opinion  of  Drs.  Sharpey  and  Carpenter,  again  referred  to 
in  the  Appendix,  and  seemingly  adopted  by  the  author,  that  the  striation,  or 
dark  spots  on  the  fibrillse,  indicate  the  cavities  of  the  cells  which  compose 
each  fibrilla,  is  more  probably  the  correct  explanation.  The  junctions  of 
these  cells,  according  to  the  same  authorities,  are  further  marked  by  delicate 
transverse  lines,  intermediate  between  the  cells.  These  lines  are  readily 
seen  in  the  muscular  fibre  of  the  pig,  with  a  power  of  600  diameters. 

That  the  striation  depends  on  the  corrugation  of  the  muscular  fibre,  a 
theory  which  the  author  seemed  disposed  to  adopt  in  his  explanation  of 
Plate  XLIIL,  fig.  6,  is  not  probable.  The  striations  are  too  regular  to  result 
from  such  cause. 

Professor  Kolliker  has  ascertained  that  non-striated  muscular  fibre  more 
generally  enters  into  the  structure  of  different  organs,  than  was  usually 
believed.  His  researches  on  this  subject  have  been  very  laborious,  and  an 
abstract  of  the  results  obtained  by  him  has  been  published  in  the  eleventh 
number  of  the  "British  and  Foreign  Medico-Chirugical  Review,"  for  July 
1850.  This  abstract  is  so  clear  and  concise,  and  affords  such  assistance  to 
the  student,  that  it  is  here  inserted. 

ON    A    NEW   FORM    OF    SMOOTH    OR    NON-STRIATED    MUSCULAR    FIBRE. 
BY    PROFESSOR    KOLLIKER. 

"Kolliker  describes  the  smooth  muscles  as  composed  of  short,  isolated  fibres, 
each  containing  a  nucleus.  He  calls  them  muscular  or  contractile  fibre-cells,  and 
gives  three  varieties: 

1.  "Short,  round,  spindle-shaped,  or  rectangular  plates,  like  those  of  epithelium, 
0-01"'  long,  and  0-006"'  broad. 

2.  "  Long  plates  of  irregular  rectangular,  spindle  or  club-like  shape,  with  fringed 
edges,  0-02'"  long,  and  0-001'"  broad. 

3.  "  Narrow,  spindle-shaped,  round,  or  flat  fibre,  with  fine  ends,  which  are  either 
straight  or  wavy,  0-02'",  or  even  0-25'"  long,  and  0-002'"  to  0'01'"  broad. 

"  The  first  and  second  of  these  forms  are  only  to  be  found  in  the  walls  of  vessels ; 
the  first  may  be  mistaken  for  the  cells  of  epithelium. 

"These  muscular  fibre-cells  are  composed  of  soft,  light  yellow  substance,  which 
swells  in  water  and  acetic  acid,  in  which  last  it  becomes  of  a  paler  colour.  There  is 
no  appreciable  difference  between  the  outer  and  inner  parts,  though  in  acetic  acid  it 
would  seem  as  if  each  fibre-cell  had  a  delicate  covering.  Their  substance  is  homo- 
geneous, with  longitudinal  stripes ;  and  they  often  contain  small  pale  granules, 
sometimes  yellow  globules  of  fat.  Each  fibre-cell  has  without  exception  a  pale 
nucleus,  sometimes  only  perceptible  in  acetic  acid.  Its  form  is  peculiar,  being  like  a 
small  staff  rounded  at  each  end.  The  substance  of  the  nucleus  is  homogeneous; 
its  length  is  0-006'"  —0-004'",  its  breadth  0-0008"  —0-00013'".  The  muscular 
fibre-cells  lying  side  by  side,  or  end  to  end,  form  the  smooth  muscles  as  they  appear 
to  the  naked  eye.     They  may  be  divided  into: 


£72  THE     SOLIDS. 

1.  "Purely  smooth  muscles  containing  no  other  tissue;  such  are  those  of  the 
nipple,  corium,  of  the  interior  of  the  eye,  of  the  intestines,  of  the  perspiratory  glands 
of  the  axilla,  of  the  cerumen  glands  ot  the  ear,  of  the  bladder,  of  the  prostate,  of  the 
vagina,  of  the  small  arteries,  of  the  veins  and  lymphatics. 

2.  "Mixed  smooth  muscles,  which  contain,  besides  the  muscular  fibre-cells,  cellu- 
lar tissue,  nuclear  fibre,  and  elastic  fibre:  such  are  the  trabecula?  of  the  spleen  and 
corpora  cavernosa  of  both  sexes.  They  are  also  found  in  the  tunica  dartos,  gall- 
ducts,  the  fibres  of  the  trigonum  vesicae,  the  circular  fibres  of  the  larger  arteries  and 
veins,  the  long  and  transverse  fibres  of  the  prostata,  urethra,  Fallopian  tubes,  and  of 
the  womb:  they  change  by  imperceptible  transitions  into  the  first  form;  this  is  the 
case  in  the  trachea,  bronchi,  urethra,  the  inner  muscular  layer  of  the  testicles, 
seminal  ducts,  &c. 

"Kolliker  says,  that  he  has  found  smooth  muscles  in  the  skin  to  a  far  greater 
extent  than  is  generally  supposed.  In  the  sub-cutaneous  cellular  membrane  of  the 
scrotum,  penis  (prepuce),  and  the  anterior  portion  of  the  perineum,  they  are  well 
developed.  The  greater  number  seems  to  exist  in  the  tunica  dartos;  in  the  peri- 
neum and  prepuce  there  are  fewer.  In  the  tunica  dartos  they  form  a  muscular  coat 
resembling,  on  a  small  scale,  the  tissue  of  the  bladder.  In  the  nipple  and  areola 
(especially  in  the  female),  the  smooth  muscles  are  strongly  developed,  somewhat 
resembling  those  of  the  tunica  dartos,  but  having  no  fibrous  covering.  In  the  areola, 
up  to  the  base  of  the  nipple,  they  are  arranged  in  circular  order;  in  the  nipple  they 
are  circular  and  vertical,  the  ducts  passing  between  them.  Some  lie  in  the  corium, 
and  form  the  corpus  reticulare;  others  belong  to  the  sub-cutaneous  tissue.  Smooth 
muscles  are  also  found  in  every  part  of  the  body  covered  with  hair,  in  the  hair-bulb, 
and  in  the  upper  portion  of  the  corium.  In  the  parts  not  covered  with  hair,  such  as 
the  palm  of  the  hand,  the  smooth  muscles  are  wanting.  One  or  two  bundles  of 
muscular  fibre  encircle  each  hair-bulb  or  sebaceous  gland.  Kolliker  remarks,  that 
the  tensor  choroidese  does  not  insert  itself  into  the  processus  ciliaris,  but  that  it  lies 
fiat  on  its  anterior  surface,  and  that  it  arises  from  the  canalis  schlemmii.  The 
sphincter  pupillae,  he  says,  may  be  easily  seen  in  the  eye  of  the  white  rabbit,  and  in 
the  blue  eye  in  man,  on  removing  the  uvea.  In  man  it  is  \'"  broad,  and  forms  the 
pupillar  edge  of  the  iris.  He  has  also  observed  a  muscular  ring  near  the  annulus 
iridis  minor.  The  dilator  pupillse  does  not  form  a  continuous  membrane,  but  seems 
to  consist  of  isolated  bundles  of  fibres  passing  between  the  muscles  to  insert  them- 
selves in  the  edge  of  the  sphincter.  He  has  never  seen  the  anastomosis  of  these 
fibres  mentioned  by  Todd  and  Bowman.  The  writer  thinks  that  the  elements  of  all 
these  muscles  are  smooth  muscular  fibre,  thougli  he  admits  that  he  has  seldom  suc- 
ceeded in  isolating  the  muscular  fibre-cells  in  the  human  body.  He  does  not  think 
that  the  M.  cochlearis  discovered  in  the  ear  by  Todd  and  Bowman  deserves  the  name 
of  a  muscle;  he  is  rather  disposed  to  consider  it  as  a  ligamentous  structure,  and  calls 
it  the  ligamentum  spirale;  he  looks  upon  it  as  a  means  of  attachment  for  the  zonula 
membranacea.  Remarking  that  the  smooth  muscles  of  the  intestines  resemble  one 
another  in  their  histological  characters,  he  points  out  one  peculiarity,  viz  :  that  they 
present  a  knotty  appearance  with  ends  running  out  into  fine  spirals.  He  thinks  that 
it  is  not  improbable  that  the  knots  are  due  to  a  contraction  of  the  fibre.  The  fibre- 
cells  of  the  intestine  seem  to  be  striped,  as  if  they  were  composed  of  an  envelope 
and  some  homogeneous  striped  contents.  No  muscular  fibre  is  found  among  them, 
but  they  are  covered  and  bound  together  by  cellular  membrane. 


MUSCLE.  373 

"  The  small  perspiratory  glands  seldom  possess  smooth  muscular  fibres,  although 
these  are  always  present  in  the  large  perspiratory  glands  of  the  axilla,  and  in  the 
cerumen  glands  of  the  ear. 

"Kolliker  does  not  admit  the  presence  of  muscular  fibre  in  the  lacteal  glands. 
"In  the  lungs  he  finds  that  the  structure  of  the  small  and  large  bronchi  is  the 
same.  Outside  of  the  epithelium  they  present  a  layer  composed  of  longitudinal 
fibres  of  areolar  tissue,  and  a  number  of  strong,  fine,  elastic  fibres.  Then  follow  one 
or  more  circular  layers  of  smooth  muscular  fibre,  with  some  nuclear  fibre  running 
transversely ;  lastly,  a  layer  of  cellular  tissue,  with  nuclear  fibre.  He  never  could 
find  muscular  fibre  running  longitudinally  through  the  bronchi.  With  respect  to  the 
vesicles  of  the  lungs,  he  could  come  to  no  satisfactory  conclusion.  Long  nuclei  are 
seen  in  the  walls  of  the  vesicles,  but  they  are  not  so  long  and  narrow  as  those  of 
the  smooth  muscles,  and  appear  to  him  to  belong  to  the  capillaries.  The  smooth 
muscles  of  the  trachea  and  bronchi  resemble  in  their  elements  those  of  the  intestines. 
In  the  ox,  the  gall-bladder,  the  ductus  cysticus,  d.  choledocus,  and  the  ducts  lying 
out  of  the  substance  of  the  liver,  present  a  large  amount  of  muscular  fibre  of  the 
smooth  species.  It  is  strongly  developed  in  the  canals,  in  which  it  is  so  disposed 
longitudinally;  in  the  gall-bladder  this  is  not  so  much  the  case,  a  transverse,  and 
even  an  oblique  layer  of  the  fibres  being  placed  between  two  longitudinal  layers. 
In  the  human  body,  the  muscular  structure  is  very  faintly  developed  in  the  gall-ducts. 
Kolliker  could  only  discover  a  very  delicate  layer  at  all  approaching  muscular  fibre. 
In  the  pancreatic  ducts  of  the  human  body,  no  trace  of  muscular  fibre  exists.  In  the 
lacrymal  apparatus  there  are  no  muscular  fibres:  in  the  ductus  stenonianus  none; 
the  ductus  whartonianus  has  a  very  faint  layer  of  smooth  muscular  fibre. 

"No  part  of  the  internal  structure  of  the  kidney  shows  traces  of  museular  fibre; 
it  is  only  in  the  calices  and  pelves  that  it  becomes  apparent.  The  muscular  fibres 
of  the  pelves  and  calices  are  composed  of  an  outer  longitudinal  coat,  and  an  inner 
transversal  layer;  they  are  continuations  of  the  same  in  the  urethra,  and  all  partake 
of  the  general  characters  of  smooth  muscular  fibre.  Supposing  the  disposition  of 
the  muscular  fibres  of  the  bladder  to  be  well  known,  the  writer  observes  that  the 
trigonum  vesicas  consists  of  a  pretty  strong  layer  of  pale  yellow  fibres  immediately 
under  the  mucous  membrane;  this  is  to  be  considered  as  an  expansion  of  the 
longitudinal  fibres  of  the  urethra. 

"  The  canaliculi  of  the  testes  have  no  muscular  fibres,  but  on  the  inner  side  of  the 
interior  surface  of  the  tunica  vaginalis  communis,  smooth  muscular  fibre  is  evident. 
The  vas  deferens  presents  a  thick  layer  of  smooth  muscular  fibre,  forming  an  outer 
longitudinal,  a  middle  transverse,  and  an  oblique  layer  directly  under  the  mucous 
membrane.  The  canaliculi  of  the  epididymis  present  the  same  conditions  of  their 
walls  as  the  vasa  deferentia.  Kolliker  thinks  he  has  seen  some  muscular  fibres  in 
the  body  of  the  epididymis.  The  ductus  ejaculatorii  are  formed  like  the  vas  defer- 
ens ;  the  seminal  vesicles  present  also  the  same  conditions.  Both  coverings  of  the 
prostate — that  derived  from  the  seminal  vesicles,  and  its  own  peculiar  covering — are 
more  or  less  muscular. 

"  The  pars  membranacea  urethrae  possesses  but  little  smooth  fibre,  compared  with 
the  prostate.  Under  the  mucous  membrane  (whose  cellular  tissue  is  rich  in  elastic 
or  nucleus-fibre)  there  is  a  layer  of  longitudinal  fibre,  mostly  composed  of  fibro- 
cellular  membrane,  containing  nuclear  fibre  and  contractile  fibre-cells:  this  layer  is 


374  THE     SOLIDS. 

succeeded  by  another  of  transverse  fibre  belonging  to  the  musculus  urethralis;  it 
also  contains  smooth  muscular  fibre.  In  the  pars  cavernosa  urethra  the  fibres  are 
but  slightly  developed;  but  they  are  still  found  at  a  certain  depth. 

"The  corpora  cavernosa  may  be  considered  as  highly  developed  muscular 
structures,  furnished  with  peculiar  blood-vessels,  since  the  smooth  muscular  fibres 
exist  in  the  fibrous  septa,  even  in  the  glans. 

"  The  inner  portions  of  the  uropoietic  viscera  in  the  female  resemble  those  of  the 
male  witli  regard  to  their  structure.  The  urethra  has,  besides  the  longitudinal 
fibres,  a  transverse  layer  of  smooth  muscular  fibre.  Fallopian  tubes  have  a  thick, 
middle  layer  of  longitudinal  and  transverse  fibre ;  the  elements  of  which  are  smooth 
muscular  fibre-cells,  with  moderate-sized  nuclei.  The  smooth  muscular  fibre  is  with 
difficulty  isolated  in  the  virgin  state ;  but  in  the  gravid  uterus  it  is  seen  in  great  per- 
fection. In  the  fifth  month  Kolliker  saw  bundles  of  red  fibre  of  the  smooth  muscular 
kind,  mixed  with  cellular  membrane,  without  nucleated  fibre;  the  fibre-cells  were 
spindle-shaped,  and  very  long.  As  pregnancy  advances,  no  new  cells  seem  to  form; 
but  those  already  formed  increase  in  size.  Sometimes  they  measure  j^" ' -\" ' ', 
they  are  spindle-shaped,  and  ran  out  into  long,  thin  tails.  After  birth,  they  rapidly 
decrease  in  size.  The  middle  or  vascular  layer  of  the  uterus  is  rich  in  smooth  mus- 
cular fibre;  it  differs  only  from  the  inner  and  outer  coat,  in  the  fibres  crossing  each 
other  in  every  direction. 

"  The  ligamenta  uteri  anteriora  et  posteriora  present  a  red  fibrous  tissue,  enclosed 
in  the  two  folds  of  the  peritoneum;  in  this,  smooth  muscular  fibre  maybe  traced. 
In  the  ligamenta  ovarii  very  few  are  found.  The  writer  says  he  has  seen  muscular 
fibre  in  the  lower  portion  of  the  anterior  fold  of  the  peritoneum;  on  the  ligamenta 
lata  these  fibres  expand  between  the  folds,  and  he  even  thinks  that  they  insert  them- 
selves in  the  walls  of  the  pelvis.  Directly  under  the  mucous  membrane  of  the 
vagina,  a  layer  of  muscular  fibre  exists,  stretching  from  the  bottom  of  the  vagina  to 
the  vestibule,  and  containing  a  thick  plexus  of  veins;  it  is  composed  of  longitudinal, 
but  more  especially  of  transverse,  long  fibre-cells,  with  wavy  ends.  The  structure 
of  the  clitoris,  glans  clitoridis,  bulbus  vestibuli,  &c,  is  analogous  to  that  of  the 
corpora  cavernosa  in  the  male. 

"In  the  spleen  of  the  human  body,  Kolliker  has  never  been  able  to  discover  smooth 
muscular  fibre,  either  in  its  covering,  or  in  the  larger  fibrous  bands;  but  in  the 
microscopical  fibrous  bands  he  has  found  elements  which  he  thinks  are  of  a  muscular 
nature.  He  also  states,  that  in  birds,  reptiles,  and  fishes  he  has  found  some  muscu- 
lar fibre  in  the  fibrous  bands  of  the  spleen.  The  existence  of  smooth  muscular 
fibre  in  the  blood-vessels  and  lymphatics  is  indubitable;  Kolliker  recommends  the 
middle-sized  arteries  and  veins  for  examination.  In  the  aorta  and  trunks  of  the 
pulmonary  arteries,  the  middle  coat  is  composed  alternately  of  muscular  and  elastic 
membrane,  with  fibro-cellular  tissue.  These  muscles  consist  of  fibre-cells,  contain- 
ing nuclei.  The  larger  veins  of  the  human  body  present,  externally  to  their  lining,  a 
single  or  double  layer  of  elastic  fibre,  a  simple  coat  of  transverse  muscular  fibre-cells, 
mixed  with  cellular  tissue,  to  which  succeeds  externally  a  coat  of  longitudinal  fibres. 
In  the  middle-sized  veins  there  is  a  middle  coat  of  a  pale  reddish  colour,  composed 
of  alternate  transverse  and  longitudinal  fibres;  the  former  are  of  fibro-cellular  tissue 
and  contractile  fibre-cells.  Towards  the  periphery,  the  muscular  structure  decreases. 
The  veins  of  the  uterus,  which  in  the  unimpregnated  state  present  no  peculiarities. 


MUSCLE.  375 

acquire  a  great  development  during  pregnancy  with  regard  to  length  and  organization. 
This  does  not  so  much  proceed  from  the  thickening  of  their  walls,  as  from  the 
increasing  size  of  the  fibre-cells  existing  in  the  middle  coat  before  pregnancy,  and  in 
certain  changes  in  the  outer  and  inner  coat  caused  by  their  acquiring  a  considerable 
quantity  of  smooth  muscular  fibre.  The  very  large  veins  which  pierce  the  inner 
muscular  coat  of  the  uterus  at  the  point  of  attachment  of  the  placenta,  and  which 
communicate  with  its  uterine  portion,  make  an  exception  to  this  rule,  as  they  have 
only  longitudinal  muscular  coats,  which  with  the  epithelium  form  the  walls  of  the 
vein. 

"The  following  veins  have  no  muscular  structure: 

1.  "  The  veins  of  the  uterine  portion  of  the  placenta. 

2.  "The  veins  of  the  cerebral  substance,  which  are  formed  of  epithelium  and 
cellular  membrane. 

3.  "  The  sinuses  of  the  dura  mater. 

4.  "Breschet's  veins  of  the  bones. 

5.  "The  venous  cells  of  the  corpora  cavernosa  in  the  male  and  female. 

6.  "Probably  the  venous  cells  ef  the  spleen.  The  muscular  fibres  of  the 
lymphatics  are  like  those  of  the  veins,  they  exist  sparingly  in  the  trunks,  and  in 
greater  number  in  the  smaller  branches." 

MANIPULATION. 

Muscular  fibre  is  best  studied  by  placing  a  small  fragment  of  muscle 
on  a  glass  slide,  moistening  it  with  water,  and  tearing  it  with  fine  needles, 
until  the  fibrillse  are  made  apparent. 

The  sarcolemma  or  sheath  of  muscular  fibre  may  be  displayed  on 
rupturing  the  fibrillse  by  tension  ;  the  sarcolemma  will  sometimes  remain 
unbroken  after  the  fibrillse  are  ruptured,  and  may  thus  be  examined.  Another 
method  is  to  immerse  the  fibre  in  water  before  irritability  be  extinguished ; 
the  fibre  imbibes  the  moisture,  then  contracts,  and  presses  out  the  fluid 
which  raises  the  sheath  into  vesicles. 

The  study  of  the  muscular  fibre  in  the  inferior  animals  is  replete  with 
interest,  the  largest  fibres  being  found  in  fishes  and  reptiles.  In  the  lobster 
and  shrimp,  the  fibrillas  are  well  seen,  even  after  they  have  been  boiled. 

The  muscular  fibre  of  the  pig  is  worthy  of  examination;  it  is  so  capable 
of  being  resolved  into  oblong  squares  by  sufficient  magnifying  power,  that 
it  has  been  adopted  as  a  test  for  object  glasses  of  high  power. 

Mr.  Quekett  states  that  the  nerves  of  muscular  fibre  are  best  studied  in 
the  thin  layer  of  muscle,  which  forms  part  of  the  abdominal  wall  of  the  frog. 
Some  of  the  capillary  vessels  maybe  also  here  seen:  these  vessels,  how- 
ever, are  best  observed  after  they  have  been  filled  with  fine  injection  when 
their  relation  to  the  primary  fasciculi  can  be  made  apparent. 

Muscular  fibre,  whether  injected  or  not,  is  best  preserved  in  fluid,  in  flat 
or  thin  glass  cells,  so  it  may  be  examined  with  high  powers.] 


376 


THE      SOLIDS. 


ART.   XIX;  —  NERVES. 


The  nervous  system  has  been  divided  into  two  orders  or  lesser 
systems;  the  cerebro-spinal,  which  includes  the  brain  and  spinal  cord, 
together  with  the  nerves  which  proceed  therefrom,  and  the  sympa- 
thetic systems.  The  former,  which  admits  of  still  further  leading 
divisions,  presides  over  animal  life,  its  nerves  administering  to  sensa- 
tion, and  being  distributed  to  the  principal  organs  of  locomotion,  the 
muscles,  as  well  as  to  those  of  the  senses;  the  latter  is  connected 
with  the  functions  of  organic  life,  and  supplies  principally  the  viscera 
and  glands  with  nerves. 

Corresponding  with  the  presumed  functional  differences  of  the  two 
systems,  there  are  also  certain  structural  differences,  the  nature  of 
which  will  shortly  be  described. 


STRUCTURE    OF    NERVES. 


Cerebro-spinae  System. — The  nervous  matter  constituting  the 
cerebro-spinal  system  consists  of  two  very  distinct  substances,  a  gray, 
cineritious,  cellular,  or  secreting  structure,  and  a  white,  conducting, 
or  tubular  structure. 

Secreting  or  Cellular  Structure. — The  very  numerous  situations 
in  which  the  gray  matter  of  the  brain  and  spinal  cord  is  encountered 
need  not  here  be  described  at  any  length:  it  will  be  sufficient  to 
observe,  that  in  the  cerebrum  it  occupies  principally  an  external  sit- 
uation, a  layer  of  it  of  about  the  one-eighth  of  an  inch  in  thickness, 
extending  over  the  entire  surface  of  its  convolutions;  but  that  it  is 
also  found  in  lesser  quantities  in  several  localities  in  the  interior  of 
the  cerebrum,  as  in  the  optic  thalami,  corpora  striata,  tuber  cinereum, 
crura  cerebri,  &c;  that,  on  the  other  hand,  in  the  cerebellum,  pons 
Varollii,  medulla  oblongata,  and  spinal  cord,  it  is  deep  seated,  forming 
the  central  portion  of  these  organs. 

The  secreting  substance,  or  gray  matter  of  the  brain,  is  made  up 
of  a  granular  base,  in  which  are  contained  numerous  nucleated  cells 
of  different  sizes  and  forms.  In  the  gray  matter  of  the  convolutions  of 
the  brain  the  granular  base  is  very  abundant,  the  cells  small  and  round, 
and  in  less  proportion  than  the  base  itself:  in  the  tuber  cinereum,  in 
the  cerebellum,  and  in  the  gray  matter  of  the  cord,  the  small  granular 
cells  are  extremely  abundant,  and  the  granular  base  is  diminished  in 
quantity.     (See  Plate  XLV.  figs.  2,  3.)  ■ 


NERVES.  377 

Now,  the  granular  base  and  the  small  granular  cells  constitute  the 
principal  portion  of  the  substance  of  the  gray  matter,  wherever- 
encountered:  in  certain  localities,  however,  cells  of  different  forms 
and  of  considerable  magnitude  are  met  with:  these  cells  have  been 
termed  ganglion  cells. 

Ganglion  Cells. — Ganglion  cells  are  encountered  in  different  por- 
tions of  the  cerebro-spinal  system,  as  in  the  locus  niger  of  the  crura 
cerebri,  in  the  gray  matter  of  the  arbor  vitas,  and  corpus  dentatum  of 
the  cerebellum;  in  the  medulla  oblongata;  in  the  spinal  cord  for  its 
entire  length,  and  according  to  Valentin  and  Purkinje,  in  all  the  extent 
of  the  cerebral  hemispheres,  especially  in  the  posterior  lobes,  and  in 
the  gray  lamina  of  the  spiral  fold  of  the  cornu  Ammonis. 

These  cells  vary  greatly  both  in  size  and  shape;  many  of  them 
attain  a  very  considerable  diameter,  and  they  are,  almost  without 
exception,  all  provided  with  caudate  prolongations,  which  are  fre- 
quently branched.     (See  Plate  XLIV.  fig.  4.) 

The  ganglioniform  cells  of  the  locus  niger  are  for  the  most  part 
small,  and  irregularly  stelliform  in  shape:  those  of  the  gray  matter 
of  the  cerebellum  are  pyriform,  the  spinous  and  often-branched 
processes,  usually  two  or  three  in  number,  proceeding  from  their 
narrow  extremities:  many  of  the  cells  of  the  medulla  oblongata  are 
triangular,  the  spines  arising  from  the  angles,  and  being  much  pro- 
duced, those  of  the  spinal  cord  are  usually  very  large,  irregular  in 
form,  and  are  furnished  with  numerous  prolongations. 

These  cells  are  highly  and  uniformly  granular:  they  frequently 
contain  pigmentary  matter,  and  enclose  a  nucleus,  which  again  is 
provided  with  its  nucleolus,  and  both  of  which  are  remarkable  for 
their  exceeding  brilliancy. 

Ganglion  cells  are,  doubtless,  connected  with  the  secretion  of  the 
nervous  element  or  fluid :  the  use  of  the  prolongations  with  which 
they  are  furnished,  and  the  precise  relation  of  these  with  the  adjacent 
structures,  the  smaller  secreting  cells  and  the  nerve  tubules,  is  not  yet 
well  ascertained:  it  has  been  conjectured,  however,  that  the  caudiform 
processes  are  directly  continuous  with  the  tubules ;  a  view  which  is 
certainly  incorrect. 

Mixed  up  with  the  ganglion  cells  wherever  met  with,  but  especially' 
with  those  occurring  in  the  gray  matter  of  the  cerebellum  and  spinal 
cord,  a  considerable  number  of  branched  and  nucleated  fibres  may  be 
seen,  similar  in  appearance  and  structure  to  those  of  unstriped  muscle, 
and  more  particularly  resembling  the  gelatinous  filaments  of  the  sym- 
pathetic system,  from  which  they  in  all  probability  really  proceed. 


378  THE     SOLIDS. 

There  is  a  second  description  of  ganglion  cell,  not  contained  in 
either  the  brain  or  spinal  cord,  but  found  in  the  various  ganglia,  as 
the  Casserian,  Optic,  Ophthalmic,  Spinal,  &c,  formed  in  connexion 
with  the  nerves  of  the  cerebro-spinal  and  sympathetic  systems,  and 
which  may  be  here  described. 

These  cells  resemble  the  ganglion  corpuscles  already  noticed  in 
their  general  structure,  but  differ  from  them  in  form,  being  more  or 
less  round  in  shape,  and  destitute  of  the  branched  processes  belonging 
to  the  latter.     (See  Plate  XLV.  fig.  4.) 

The  mode  of  multiplication  of  ganglion  cells  is  not  well  understood : 
it  is  possible  that  the  numerous  granules  contained  in  each  are  the 
germs  of  the  future  cells  Adhering  to  the  surface  of  many  of  the 
larger  ganglion  cells  of  the  second  form,  a  number  of  nucleated  par- 
ticles or  lesser  cells  may  frequently  be  observed,  forming  a  kind  of 
capsule  around  them,  which,  however,  is  entirely  external  to  the 
proper  membrane  of  the  cells.     (See  Plate  XLV.  fig.  4.) 

Tubular  Structure. — The  white  fibrous  substance  of  the  brain, 
spinal  cord,  the  nerves  of  motion  and  of  special  sensation,  is  composed 
of  unbranched  tubules,  the  diameter  of  which  is  subject  to  considerable 
variation.  The  tubules  of  the  cerebrum  are  exceedingly  slender,  as 
are  also  those  of  the  nerves  of  special  sense :  those  of  the  cerebellum, 
spinal  cord,  posterior  root  of  spinal  nerves,  and  of  the  sympathetic 
system,  are  of  somewhat  larger  calibre,  while  those  of  the  motor 
nerves  are  of  still  larger  size,  and  of  firmer  texture.  See  the  figures. 
The  tubules  of  the  white  substance  of  the  cerebrum  are  especially 
prone  to  become  dilated  at  intervals,  or  varicose.  (See  Plate  XLIV. 
fig.  7.)  This  condition  was  formerly  supposed  to  be  natural,  and  it 
was  presumed  that  by  this  character  the  nerves  of  special  sense 
could  be  discriminated  from  those  of  motion:  there  is  little  doubt, 
however,  but  that  this  varicose  condition  of  the  fibres  is  abnormal, 
and  that  it  is  produced  by  the  pressure  and  disturbance  to  which 
they  are  subject  during  examination.  The  tubules  of  the  cerebellum 
are  subject  to  a  like  change,  although  in  a  less  degree;  those  of  the 
nerves  of  motion  are  but  little  prone  to  the  alteration,  these  becoming, 
when  much  disturbed,  broken  into  fragments,  many  of  which  assume 
a  globular  form,  and  all  of  which  are  greatly  corrugated.  (See  Plate 
XUY.  fig.  1.) 

The  nerve  tubules  contain  a  fluid  matter,  and  it  is  the  collection 
of  this  fluid  in  certain  parts  of  each  tubule,  the  result  of  pressure, 
which  occasions  the  distension  of  the  membranous  wall  of  the  tubes. 


NERVES.  3T9 

and  which  gives  rise  to  the  varicose  condition  described.  Such  is, 
at  least,  the  most  probable  explanation  of  the  exact  nature  of  this 
condition. 

The  tubules  of  the  cerebrum,  cerebellum,  spinal  cord,  and  motor 
nerves,  &c,  present  an  average  diameter:  nevertheless,  much  differ- 
ence may  be  detected  in  the  size  of  the  tubules  taken  from  the  same 
portion  of  the  nervous  system :  those  of  the  spinal  cord  agree  in  their 
average  size  with  those  of  the  cerebellum. 

The  tubes  of  the  cerebrum,  of  the  nerves  of  special  sense,  and  of 
the  cerebellum,  are  so  small,  that  it  is  impossible  to  ascertain  with 
certainty  the  amount  of  organization  which  really  belongs  to  them : 
this,  however,  is  not  the  case  with  those  of  the  motor  nerves,  which 
are  so  much  larger.     (See  Plate  XLIV.  jig.  1.) 

Each  tube  of  a  motor  nerve  consists  of  an  investing  sheath  or 
neurilemma,  an  inner  elastic  and  but  little  consistent  matter,  the 
"white  substance  of  Schwann,"  which  forms  a  pseudo  membrane, 
and  which  includes  the  third  constituent  of  the  nerve  tube,  a  soft  and 
semi-fluid  matter,  which,  however,  would  appear  in  some  cases  to 
become  solid,  and  to  exhibit  a  fibrous  fracture:  this  matter  has  been 
termed  the  "axis  cylinder." 

It  is  a  matter  of  some  difficulty  to  display  the  investing  sheath,  or 
neurilemma,  around  the  fibres  in  their  fresh  and  unaltered  state:  it 
may,  however,  be  easily  detected,  and  its  structure 'recognised  in  a 
portion  of  motor  nerve  which  has  been  immersed  for  some  hours  in 
spirit :  it  will  then  be  seen  that  it  is  made  up  of  nucleated  fibres,  the 
nuclei  in  the  sheath  of  fcetal  nerve  tubes  being  of  considerable  size, 
and  presenting  a  smooth  aspect.     (See  Plate  XLIV.  jig.  2.) 

Todd  and  Bowman  describe  the  outer  membrane  of  the  nerve 
tube,  and  to  which  alone  the  word  neurilemma  should  be  applied, 
"as  an  homogenous  and  probably  elastic  tissue  of  extreme  delicacy, 
analogous  to  the  sarcolemma  of  striped  muscle,  and,  according  to  our 
observation,  not  presenting  any  such  distinct  longitudinal  or  oblique 
fibres  in  its  composition  as  have  been  described  by  some  writers." 
It  will  be  observed  that  this  description  does  not  accord  with  that 
given  by  the  author. 

The  white  substance  of  Schwann,  on  the  contrary,  is  best  seen  in 
the  motor  nerve  tubes,  which  are  perfectly  recent,  and  which  have 
been  but  little  disturbed :  its  thickness  is  indicated  by  a  double  line 
which  runs  along  each  side  of  the  tube :  it  does  not  present  any  trace 
of  organization :  it  is  very  elastic,  and  its  contraction  gives  rise  to  the 


380  THE     SOLIDS. 

corrugated  appearance  presented  by  the  tubes  of  motor  nerves  which 
have  been  disturbed  and  broken.     (Plate  XLIV.  fig.  1.) 

The  existence  of  -the  third  constituent  of  the  nerve  tube,  the  "axis 
cylinder"  of  Rosenthal  and  Purkinje,  is  best  determined  by  the  immer- 
sion of  the  fibres  in  either  ether  or  acetic  acid,  which  breaks  it  up  into 
granules  and  vesicles.     (Plate  HJAV.fig.  3.) 

In  albumen  the  nerve  tubes  and  nervous  tissue  in  general  undergo 
but  little  alteration,  and  it  is  therefore  in  this  fluid  that  its  examination 
is  best  conducted. 

But  the  tubes  of  the  white  fibrous  material  of  the  cerebrum, 
cerebellum,  and  spinal  marrow,  just  described,  form  one  element  only 
of  its  structure;  another  is  invariably  present,  forming  indeed  the 
greater  portion  of  its  substance;  and  it  is  somewhat  strange  that  it 
should  have  been  overlooked  by  observers:  this  element  consists  of 
globules  of  every  possible  size,  which,  when  free  from  pressure  and 
undisturbed,  are  perfectly  spherical,  but  which  are  put  out  of  shape 
by  the  slightest  compression  or  disturbance.  It  is  not  easy  to  deter- 
mine whether  these  globules  are  true  cells  or  not:  they  present  the 
greatest  possible  variety  of  size :  they  have  the  colour  and  consistence 
of  oil;  but  nevertheless  appear  to  be  hollow,  and  frequently  present  a 
spot  which  bears  much  resemblance  to  a  nucleus.  (See  Plate  XLIV. 
fig.  6.) 

It  now  only  remains  to  be  observed,  that  the  nerves  of  special 
sense,  as  the  optic,  olfactory,  and  auditory,  present  a  structure  pre- 
cisely analogous  to  that  of  the  white  substance  of  the  cerebrum. 

Sympathetic  System. — The  nerves  entering  into  the  formation 
of  the  sympathetic  or  organic  system,  differ  both  in  appearance  and 
structure  from  those  derived  from  the  cerebro- spinal  system:  thus, 
the  great  sympathetic  cord  itself,  as  well  as  the  organic  nerves  con- 
nected with  it,  present  a  reddish  gray  colour,  are  soft  and  gelatinous, 
and  do  not  readily  admit  of  division  in  the  longitudinal  direction, 
although  they  are  easily  torn  across  by  any  extending  force :  these 
differences  of  colour  and  of  consistence  are  dependent  upon  a  differ- 
ence of  structure.  The  great  sympathetic  cord  itself,  and  the  organic 
nerves  connected  with  it,  are  composed  of  two  distinct  descriptions 
of  fibre;  first,  of  the  ordinary  tubular  fibre,  which,  however,  is  of 
small  diameter,  and  therefore  readily  becomes  varicose,  and  second, 
of  nucleated  filaments,  in  every  appreciable  respect  resembling  those 
of  unstriped  muscular  fibre.  Henle  has  called  these  fibres  "gelatinous 
nerve  fibres." 


NERVES.  381 

The  relative  proportions  existing  between  these  two  kinds  of  fibre 
differ  in  different  nerves :  thus,  in  some  cases,  the  gelatinous  fibres 
are  by  far  the  most  numerous ;  in  others,  the  tubular  fibres  prepon- 
derate. The  gelatinous  or  gray  filaments  are  best  seen  in  what  are 
called  the  roots  of  the  sympathetic ;  that  is  to  say,  in  the  branches 
which,  accompanying  the  carotid  artery,  proceed  from  the  superior 
cervical  ganglion  to  the  fifth  and  sixth  pair  of  cerebral  nerves,  and  in 
those  which  descend  from  the  same  ganglion  and  follow  the  course 
of  the  carotid.  In  these  the  proportion  of  tubular  fibres'  is  but  small, 
as  one  to  six;  and  they  are  also  isolated  from  each  other,  each  being 
surrounded  with  a  number  of  gelatinous  fibres.  This  disposition  of 
the  nucleated  fibres  has  led  Valentin  to  consider  that  they  form  a 
sheath  around  the  tubular  fibres,  each  gray  nerve,  according  to  that 
observer,  being  composed  of  a  number  of  fascicles  or  bundles.  Henle, 
however,  objects  to  this  view,  considering  that  the  fibres  are  too  large 
for  a  sheath,  and  remarking  that  the  gray  nerves  do  not  separate  into 
such  bundles,  but  divide  much  more  readily  in  such  a  way  as  that  the 
tubular  fibre,  is  found  at  the  border  of  the  bundle.  Henle,  therefore, 
considers  it  to  be  more  natural  to  regard  the  gray  nerves  as  forming 
solid  threads,  composed  of  nucleated  filaments,  between  which  the 
tubular  fibres  run. 

The  tubular  fibres  are  more  numerous  than  in  the  roots  of  the 
great  sympathetic,  in  the  majority  of  the  visceral  nerves,  in  the 
branches  which  proceed  from  the  cardiac  and  hypo-gastric  plexuses, 
&c;  in  these  the  tubular  fibres  may  be  seen  enclosed  within  the  gray 
filaments,  forming  many  bundles.  Their  number  becomes  still  more 
considerable  in  the  great  sympathetic  cord  itself  and  the  splanchnic 
nerves;  the  cardiac  nerves  are  almost  entirely  formed  of  tubular 
fibres.  In  all  these  nerves  the  tubular  fibres  are  observed  to  be  of 
smaller  diameter  than  they  are  in  those  which  are  distributed  to  the 
voluntary  muscles. 

In  consequence  of  the  great  difference  which  exists  between  the 
structure  of  the  tubular  nerve  fibre  and  that  of  the  gelatinous  nerve 
fibre,  it  has  been  a  matter  of  doubt  with  some  observers  whether  the 
latter  should  be  regarded  as  a  true  nerve  fibre  or  not. 

The  following  is  a  brief  enumeration  of  the  various  anatomical 
and  microscopical  facts  hitherto  recorded,  both  in  favour  of  and 
opposed  to  the  opinion  of  the  nervous  character  of  the  gelatinous 
filaments  just  described. 

The  chief  structural  considerations  which  may  be  urged  in  favour 


382  THE     SOLIDS. 

of  the  opinion  that  the  nucleated  filaments  associated  with  the  various 
nerves  of  the  sympathetic  system  are  true  nerve  filaments  are — 

1st.  The  origin  of  the  gelatinous  filaments  from  the  ganglia  of  the 
sympathetic,  as  first  distinctly  affirmed  in  the  researches  of  Volkmann 
and  Bidder.* 

2d.  The  tubular  character  of  these  filaments,  as  shown  by  T. 
Wharton  Jones. f 

3d.  The  peripheral  distribution  of  the  gelatinous  filaments,  as 
asserted  by  many  observers,  but  particularly  by  Bidder,  who  even 
states  that  he  succeeded  in  counting  their  number  in  the  transparent 
septum  of  the  auricles  of  the  frog's  heart. 

4th.  The  peculiar  structure  of  the  ganglion  caecum,  discovered  by 
Mr.  T.  Wharton  Jones,  in  connexion  with  one  of  the  ciliary  nerves 
of  the  dog.  J 

5th.  The  variable,  yet  fixed  proportions  of  gelatinous  and  tubular 
fibres  occurring  in  different  nerves,  as  described  especially  by  Henle. 

6th.  The  occurrence,  as  stated  by  Todd  and  Bowman,  of  nucleated 
filaments  very  similar  to  the  gelatinous  fibres  of  the  sympathetic,  "in 
parts  where  their  nervous  character  is  indubitable,  as  in  the  olfactory 
filaments,  and  the  nerve  in  the  axis  of  the  Pacinian  corpuscle,  exhibits 
very  much  the  same  appearance,  save  that  it  is  devoid  of  nuclei. "§ 

7th.  The  resemblance  borne,  according  to  the  observations  of 
Schwann, ||  between  the  tubular  nerve  fibre  in  the  early  stages  of  its 
development,  in  which  it  is  described  as  being  nucleated,  and  the 
adult  gelatinous  fibre. 

8th.  The  origin  of  the  gelatinous  filaments  from  the  cells  themselves 
composing  the  ganglia  of  the  sympathetic,  as  the  observations  of 
several  observers  tend  to  prove. 

These  various  facts  thus  briefly  referred  to,  could  they  all  be  fully 
depended  upon,  would,  doubtless,  make  out  not  merely  a  strong,  but 
even  a  convincing  and  unanswerable  case  in  favour  of  the  nervous 
character  of  the  gelatinous  filaments:  unfortunately,  however,  those 
facts  which,  if  they  could  be  relied  upon,  would  be  the  most  conclu- 
sive, are  open  to  question:  such,  for  instance,  as  the  peripheral 
distribution  of  the  gelatinous  filaments,  their  presumed  origin  from 

*  Die  Selbstandigkeit  des  Sympathislten  Nervensyslems  durch  Analomische  Unter- 
suchungen  nachgewiesen  Von  J.  H.  Bidder  und  A.  W.  W.  Volkmann.     Leipsig,  1842. 
f  Lancet,  April  24th,  1847.  \  Lancet,  November  14th,  1846. 

§  Physiological  Anatomy,  part  hi.  p.  142. 
11  See  Wagner's  Physiology,  translation  by  Willis. 


NERVES.  383 

the  ganglionic  corpuscles,  and  the  asserted  resemblance  between  the 
tubular  nerve  fibre  in  an  early  stage  of  its  development  and  the  fully- 
grown  gelatinous  filament:  it  will  presently  be  shown,  indeed,  in  the 
observations  on  the  growth  of  the  primitive  nerve  tubule,  that  no 
such  resemblance  exists. 

Subtracting,  then,  the  points  referred  to  in  the  3d,  7th.  and  8th 
headings,  no  one  conclusive  fact  remains  of  the  position  that  the 
gelatinous  fibres  are  really  nervous. 

Against  the  opinion  that  the  gelatinous  filaments  are  nervous,  may 
be  urged : 

1st.  The  positive  structural  identity  between  the  gelatinous  nerve 
filament  and  the  fibrilla  of  unstriped  muscle,  and  the  great  improba- 
bility, as  a  consequence,  that  one  and  the  same  structure  should  have 
to  perform  two  such  distinct  functions  as  must  necessarily  belong  to 
a  muscular  fibre  and  a  nerve  tube. 

2d.  The  apparent  structural  unfitness  of  nucleated  filaments  to 
serve  as  a  conducting  medium  of  the  nervous  force. 

3d.  The  evidently  tubular  character  of  the  nerve  filaments  in  parts 
which,  from  their  nature,  we  should  expect  would  be  preeminently 
supplied  by  the  gelatinous  filaments. 

4th.  The  fact  of  the  non-occurrence  of  gelatinous  fibres,  separate 
from  the  tubular,  is  strongly  opposed  to  the  idea  of  the  independence 
of  the  former. 

The  above  short  summary  will  serve  to  give  some  idea  of  the  state 
of  the  much-canvassed  question  of  the  nervous  or  non-nervous  char- 
acter of  the  gray  or  gelatinous  filaments  of  the  sympathetic. 

STRUCTURE    OF    GANGLIA. 

The  ganglia  consist  of  the  peculiar  globules  already  described,  of 
nerve  tubules,  and  of  gelatinous  filaments. 

Each  ganglion  is  enclosed  in  an  investing  tunic  of  fibrous  tissue? 
a  continuation  of  the  common  envelope  of  the  nerves  which  enter  and 
depart  from  it,  and  which  sends  down  dissepiments  which  divide  the 
contained  globules  into  parcels,  and  thereby  give  the  ganglion  the  gen- 
eral arrangement  and  character  of  a  gland. 

The  gelatinous  nerve  filaments  in  the  ganglion  form  a  kind  of  inner 
capsule,  and  their  arrangement  is  thus  described  by  Henle:  "Besides 
the  nervous  fibres  properly  so  called  of  the  soft  nerves,  one  meets 
with  also,  in  the  ganglions  of  the  great  sympathetic,  gelatinous  fibres 
which  have  special  relations  with  the  ganglionic  globules.     The  fibres 


384  THE     SOLIDS. 

of  a  bundle  expand  in  the  form  of  a  funnel,  in  order  to  embrace  a 
globule  or  a  series  of  globules,  and  unite  together  afterwards  afresh, 
to  separate  again  a  second  time.  In  this  way  we  often  come  to  draw 
out  of  a  ganglion  entire  threads  of  gelatinous  fibres,  which  are  dilated, 
in  the  manner  of  a  chain  of  pearls,  and  enclosing  the  globules  in  their 
dilatations." 

The  proper  tubular  fibres  enter  the  divisions  of  the  ganglion  in 
bundles,  subsequently  separate  from  each  other,  and  ramify  among  the 
ganglion  globules  in  a  waved  and  serpentine  manner. 

The  arrangement  of  the  ganglion  globules  and  nerve  tubules  just 
indicated,  tends  to  show  that  these  are  really  the  only  essential 
elements  of  a  ganglion. 

The  ganglia  are  supplied  with  blood-vessels. 

It  will  be  apparent  from  the  above  description  that  the  ganglia  have 
all  the  structural  characteristics  of  glands,  and  therefore  there  can 
be  little  question  but  that  they  are  really  glandular  organs,  and  that 
the  tubular  fibres  which  pass  through  them  carry  away  the  fluid, 
which  is  destined  to  exercise  its  influence  on  the  parts  and  organs  to 
which  the  nerves  are  themselves  distributed. 

The  question  as  to  the  origin  of  either  the. tubular  fibre  or  the  gela- 
tinous filament  from  the  ganglionary  corpuscles,  is  still  an  undecided 
one,  the  weight  of  evidence  being  opposed  to  the  idea  that  either  order 
of  fibres  has  any  origin  from  these  corpuscles. 

ORIGIN    AND    TERMINATION    OF    NERVES. 

Origin. — But  little  that  is  certain  is  known  respecting  the  exact 
mode  of  origin  of  the  numerous  tubules  composing  the  nerves,  and  of 
the  precise  relation  of  these  with  the  cellular  or  secreting  element  of 
the  ganglionic  centres.  The  observations  of  Dr.  Lonsdale,*  however, 
render  it  highly  probable  that  the  greater  portion  at  least  of  the  nerve 
tubes  have  a  looped  origin  in  the  brain  and  spinal  cord :  that  gentle- 
man having  made  out  the  interesting  fact,  that  in  two  fetuses,  in  the 
one  of  which  both  the  brain  and  spinal  cord  were  deficient,  and  in  the 
other  the  brain  only,  the  extremities  of  the  nerves,  which  extended 
into  the  cavities  of  the  spinal  column  and  cranium,  were  made  up  of 
looped  nerve  tubes  imbedded  in  an  imperfectly  developed  granular  and 
cellular  matter,  apparently  of  a  ganglionic  character.  Now,  from 
what  is  known  respecting  the  laws  of  development,  it  would  appear  to 

*  Edinburgh  Medical  and  Surgical  Journal,  No.  cxvii. 


NERVES.  3S"> 

be  a  perfectly  justifiable  and  natural  inference,  that  the  nerve  tubes, 
when  fully  developed,  have  a  similar  mode  of  origin. 

According  to  some  observers,  certain  nerve  tubes  are  connected 
with  and  take  their  origin  from  the  prolongations  with  which  the  cau- 
date variety  of  ganglionary  cells  are  provided ;  this  view,  however,  is 
confidently  denied  by  many  other  investigators,  and  the  point  is  one 
which  is  still  involved  in  considerable  uncertainty :  for  myself,  I  would 
observe,  that  I  have  never  succeeded  in  making  a  single  observation 
favourable  to  such  a  conclusion.  Notwithstanding,  however,  the 
doubts  which  are  now  entertained  respecting  the  modes  of  origin  of 
nerve  tubes,  the  question  is  assuredly  one  which,  at  some  future  day, 
will  be  satisfactorily  determined  by  direct  observation. 

It  is  also  still  uncertain  whether  nerve  tubules  originate  in  the 
ganglia  not  included  in  the  brain,  as  in  those  connected  with  the 
encephalic  nerves,  and  those  of  the  sympathetic  system. 

When  speaking  in  the  preceding  remarks  of  the  origin  of  nerves, 
that  extremity  of  them  is  implied  which  is  in  connexion  with  the  brain 
and  spinal  cord:  it  is  questionable,  however,  in  the  case  of  the  nerves 
of  special  sense,  whether  it  would  not  be  more  proper  to  consider 
their  peripheral  rather  than  their  central  extremities  as  their  true 
origins;  a  view  supported  by  the  consideration  that  the  .sensations 
arise  in,  and  proceed  from,  the  organs  of  the  senses  inwards  towards 
the  brain,  the  great  centre  of  nervous  structure  and  force,  as  well  as 
by  the  fact,  that  the  peripheral  extremities  of  these  nerves  are  gener- 
ally, if  not  invariably,  connected  with  ganglionic  cells;  such  an 
association  of  the  two  elements  is  known  to  exist  in  the  eye,  in  the 
ear,  in  the  nose,  and  probably  exists  also  in  the  papillae  of  the  tongue 
and  skin. 

Termination. — It  was  not  known  until  within  the  last  four  or  five 
years  that  nerves  had  any  real  termination:  it  was  up  to  that  time 
generally  considered  that  the  nerve  tubes  invariably  ended  in  the 
same  manner  as  it  is  now  supposed  that  they  originate,  viz :  in  loops ; 
and  there  can  be  little  question  but  that  such  a  mode  of  termination, 
though  not  universal,  is  at  least  very  frequent:  thus,  the  arrangement 
of  the  primitive  nerve  fibres  in  loops  has  been  described  by  Valentin, 
in  the  pulps  of  the  teeth;  by  Muller,  in  the  membrana  nictitans,  and 
in  the  mucous  membrane  of  the  throat  of  the  frog;  in  the  papillae  of 
the  skin  and  tongue,  by  Todd  and  Bowman.  The  loops  are  formed 
by  one  or  more  of  the  nerve  tubes,  separating  themselves  from  the 
bundle  of  tubes  composing  every  nerve  of  any  magnitude,  and  after- 

•25 


386  THE     SOLIDS. 

wards  either  passing  into  and  mingling  with  those  of  a  neighbouring 
nerve,  or  else  returning  back  to  that  from  which  originally  it  started. 
It  is  now,  however,  very  certain  that  some  at  least  of  the  nerve 
tubes  have  a  real  termination :  this  is  indisputably  the  case  with  the 
single  filaments  which  enter  the  Pacinian  bodies;  it  has  also  been  shown 
to  occur  with  many  of  the  primitive  tubes  distributed  to  muscles. 

PACINIAN    BODIES.* 

The  Pacinian  bodies  are  found  in  considerable  numbers  attached 
to  the  cutaneous  nerves  of  the  hands  and  feet,  especially  to  those  of 
the  extremities  of  the  fingers  and  toes ;  they  are  also  met  with,  though 
more  sparingly,  on  other  spinal  nerves,  on  the  plexuses  of  the  sympa- 
thetic, but  never  on  the  nerves  of  motion,  and  in  the  mesentery ;  in 
that  of  the  human  subject,  however,  they  are  only  with  great  difficulty 
to  be  discovered,  owing  to  its  thickness,  and  the  quantity  of  fat  usually 
contained  in  it :  in  the  mesentery  of  the  smaller  mammalia,  as  the  cat, 
rabbit,  &c,  and  more  particularly  when  these  are  in  a  lean  state,  they 
may  be  readily  discerned  with  the  naked  eye,  and  the  entire  of  their 
structure  followed  out  without  even  the  employment  of  a  reagent:  it 
is,  therefore,  in  these  animals  that  they  are  studied  to  most  advantage. 

The  Pacinian  bodies  vary  greatly  in  size,  but  are  usually  as  large 
as  the  head  of  a  pin  of  ordinary  magnitude;  they  are  of  an  oval  or 
pyriform  shape,  are  perfectly  translucent,  attached  to  the  nerve 
filaments  by  short  pedicles,  and  occur  either  singly  or  sometimes  in 
pairs.     (See  Plate  XL VI.  fig.  1.) 

So  large  are  these  peculiar  bodies,  that  the  whole  of  their  structure 
may  be  followed  out  with  object  glasses  of  an  inch  and  half-inch  foci; 
when  examined  with  these  magnifying  powers,  each  Pacinian  body  is 
observed  to  consist  of  numerous  concentric  lamellae  or  capsules 
disposed  with  much  regularity;  these  lamellae  are  formed  of  white 
fibrous  tissue,  contain  numerous  nuclei  in  their  substance,  and  are- 
separated  from  each  other  by  distinct  intervals  which  contain  fluid ; 
the  spaces  intervening  between  the  plates  do  not  communicate  and 
diminish  gradually,  but  regularly  from  without  inwards,  so  that  the 

*  The  discovery  of  these  remarkable  bodies  constitutes  one  of  the  happiest  and 
most  beautiful  results  of  the  application  of  the  microscope  to  minute  anatomy. 
Pacini  first  noticed  them  in  1830,  subsequently  in  1835;  but  it  was  not  until  1840 
that  he  gave  an  account  of  them. — (Nuoci  organi  scoperli  nel  Corpo  umano  dal  Dolt 
Filippo  Pacini,  Pislqja.)  A.  G.  Andral,  Camus,  and  Lacroix,  announced  their  exists 
ence  at  a  Concours  at  Paris,  in  1833,  but  do  not  appear  to  have  recognised  their  real 
character. 


NERVES.  387 

central  lamellae  are  almost  in  contact  with  each  other,  from  which 
cause  they  present  a  darker  aspect  than  do  those  having  appreciable 
spaces  dividing  them  the  one  from  the  other:  these  capsules  have 
been  distinguished  from  the  rest  by  the  term  the  "inner  system  of 
capsules."  It  is  this  regular  disposition  of  the  lamella?,  together  with 
their  gradual  approximation,  which  imparts  so  beautiful  an  appearance 
to  these  strangely  constituted  organs.  The  capsules,  however,  are 
not  continued  to  the  very  centre  of  the  Pacinian  body;  but  in  that 
situation  a  cavity,  having  a  somewhat  elliptical  form,  and  filled  with 
fluid,  exists.  This  cavity  opens  externally  by  means  of  a  canal  which 
pierces  the  whole  of  the  lamellae,  and  the  sides  of  which  canal  are 
formed  by  the  union  of  those  lamellae  ;  into  this  canal  a  single  nerve 
tube  passes,  enters  the  central  cavity  just  described,  which  it  trav- 
erses from  end  to  end  in  a  straight  line,  terminating  in  a  slightly 
enlarged  extremity,  which  is  described  as  being  attached  to  the  inner 
wall  of  the  distal  end  of  the  central  chamber;  the  nerve  tube,  imme- 
diately on  its  entrance  into  this  chamber,  loses  its  double  and  defined 
border,  in  consequence,  it  is  presumed,  of  the  absence  of  the  white 
substance  of  Schwann.     (Plate  XLVI.  figs.  2,  3.) 

Such  is  a  brief  and  general  description  of  the  Pacinian  body ;  one 
or  two  other  points  of  a  less  evident  character  still  remain  to  be 
noticed.  It  has  been  stated  that  the  capsules  contain  elongated 
nuclei  in  their  parietes,  that  they  are  formed  of  fibrous  tissue,  and 
that  the  spaces  between  them  have  no  communication  with  each 
other:  if  the  outer  and  larger  capsules  be  carefully  examined,  it  will 
frequently  be  observed  that  they  present  a  double  edge,  separated  by 
a  faint  interval,  and  conveying  the  impression  that  each  capsule  is 
made  up  of  two  distinct  membranes ;  it  is  in  this  interval  that  the 
nuclei  are  lodged:  that  the  inter-capsular  spaces  do  not  communicate 
with  each  other,  is  proved  by  the  fact,  that  when  the  outer  capsules 
are  pierced  through,  the  fluid  escapes  only  from  the  spaces  which 
have  been  opened  into;  if  the  whole  of  the  capsules  have  been 
divided,  the  entire  corpuscle  immediately  collapses.  (It  is  a  curious 
fact  that  a  Pacinian  body,  allowed  to  dry  up,  does  not  again  absorb 
fluid,  and  expand  to  its  natural  size.)  It  has  also  been  observed  that 
the  capsules  are  united  to  each  other  at  the  proximate  extremity  of 
the  Pacinian  body  along  the  sides  of  the  canal  already  described: 
according  to  Pacini,  they  are  also  bound  together  at  the  distal  end  by 
a  band  of  fibrous  tissue,  which  he  calls  the  "inter-capsular  liga- 
ment :"  the  existence  of  this  ligament  has  been  denied  by  Henle  and 


88S 


THE     SOLIDS. 


Kolliker.*  Todd  and  Bowman  do  not  deny  its  existence,  but  state 
that  they  have  seldom  seen  it  reach  the  surface  of  the  corpuscle.")" 

Pacinian  bodies  not  unfrequently  present  varieties  of  form  and 
structure:  it  is  possible  that  many  of  these  admit  of  explanation  on 
the  supposition  that  in  some  instances  they  are  multiplied  by  self- 
division:  thus,  sometimes  the  distal  end  of  the  central  chamber  is 
bifid,  the  nerve  tube  being  also  divided;  in  others,  a  single  corpuscle 
will  be  found  to  contain  two  distinct  chambers  and  nerve  tubes,  each 
being  surrounded  by  a  certain  number  of  capsules,  but  which  again 
are  themselves  included  in  a  number  of  other  capsules  which  embrace 
both  the  sets  of  inner  membranes:  again,  in  other  instances,  two 
Pacinian  corpuscles,  entirely  formed,  but  yet  not  altogether  separated 
from  each  other,  being  connected  by  a  few  of  the  capsules,  will  be 
situated  upon  a  single  primitive  nerve  tube:  a  fourth  peculiarity, 
which  may  be  noticed  more  frequently  than  any  of  the  others,  is  the 
curling  back  of  the  extremity  of  the  central  chamber,  the  innermost 
capsules  describing  the  same  curvature.     (See  Plate  HhYI.figs.  4,  5.) 

•DEVELOPMENT    AND    REGENERATION    OF    NERVOUS    TISSUE. 

Development  of  nerve  fibres. — The  following  is  the  account  given 
by  Schwann  of  the  development  of  the  nervous  cords  as  rendered  by 
Willis  in  his  translation  of  Wagner's  "Physiology,"  the  references  to 
the  figures  only  being  omitted.  "The  nerves  appear  to  be  formed 
after  the  same  manner  as  the  muscles,  viz :  by  the  fusion  of  a  number 
of  primary  cells,  arranged  in  rows  into  a  secondary  cell.  The  primary 
nervous  cell,  however,  has  not  yet  been  seen  with  perfect  precision, 
by  reason  of  the  difficulty  of  distinguishing  nervous  cells  while  yet 
in  their  primary  state  from  the  indifferent  cells  out  of  which  entire 
organs  are  evolved.  When  first  a  nerve  can  be  distinguished  as  such, 
it  presents  itself  as  a  pale  cord  with  a  longitudinal  fibrillation,  and  in 
this  cord  a  multitude  of  nuclei  are  apparent.     It  is  easy  to  detach 

individual  filaments  from  a  cord  of  this  kind, in  the  interior 

of  which  many  nuclei  are  included,  similar  to  those  of  the  primitive 
muscular  fasiculus,  but  at  a  greater  distance  from  one  another.  The 
filaments  are  pale,  granulated,  and  (as  appears  by  their  farther  devel- 
opment) hollow.  At  this  period,  as  in  muscle,  a  secondary  deposit 
takes  place   upon  the   inner  aspect   of  the  cell  membrane  of  the 

*  Ueber  die  Pacinisclien  Kbrperchen  an  den  Nerven  des  Menschen  und  der  Sauge- 
ihiere.    Zurich,  1844. 

f  Physiological  Anatomy,  vol.  i.  p.  397. 


NERVES.  389 

secondary  nervous  cell.  This  secondary  deposit  is  a  fatty  white- 
coloured  substance,  and  it  is  through  this  that  the  nerve  acquires  its 
opacity.  With  the  advance  of  the  secondary  deposit,  the  fibrils 
become  so  thick,  that  the  double  outline  of  their  parietes  comes  into 
view,  and  they  acquire  a  tubular  appearance.  On  the  occurrence  of 
this  secondary  deposit,  the  nuclei  of  the  cells  are  generally  absorbed ; 
yet  a  few  may  still  be  found  to  remain  for  some  time  longer,  when 
they  are  observed  lying  outwardly  between  the  deposited  substance 
and  the  cell  membrane,  as  in  the  muscles.  The  remaining  cavity 
appears  to  be  filled  by  a  pretty  consistent  substance,  the  band  of 
Remak,  and  discovered  by  him.  In  the  adult,  a  nerve,  consequently, 
consists,  1st,  of  an  outer  pale  thin  cell  membrane — the  membrane  of 
the  original  constituent  cells,  which  becomes  visible  when  the  white 
substance  is  destroyed  by  degrees;  2d,  of  a  white  fatty  substance, 
deposited  on  the  inner  aspect  of  the  cell  membrane,  and  of  greater  or 
less  thickness;  3d,  of  a  substance,  which  is  frequently  firm  or  consist- 
ent, included  within  the  cells,  the  band  of  Remak." 

The  author's  observations  lead  him  to  entertain  views  of  the  devel- 
opment of  the  primitive  nerve  tube  essentially  distinct  from  those 
expressed  by  Schwann  in  the  account  quoted  above :  according  to 
these  observations,  the  outer  covering  of  the  nerve  tube  does  not 
consist  of  a  structureless  membrane,  as  is  supposed  by  Schwann,  as 
well  as  most  other  observers,  but  is  constituted  of  a  nucleated  form 
of  fibrous  tissue.  (See  Plate  XLIV.  jig.  2.)  Now,  the  nuclei 
observed  by  Schwann  the  author  believes  to  be  concerned  in  the 
development  of  the  fibres,  of  which  the  proper  membrane  of  each 
primitive  nerve  tube  is  wholly  constituted,  and  that  they  do  not  by 
their  growth  give  origin  to  a  transparent  tubular  membrane. 

In  the  nerve  tubes  of  both  young  and  adult  animals,  smooth  bodies 
of  an  oval  form  and  large  size,  their  diameter  exceeding  that  of  the 
tube  itself,  may  always  be  observed ;  the  nature  of  these,  and  the 
part  taken  by  them  in  the  structure  and  development  of  the  nerve 
tube,  I  have  not  been  able  to  determine. 

Development  of  Glandular  Nerve  or  Ganglionary  Cells. — The 
nervous  matter  composing  the  two  or  three  systems  into  which,  in 
the  present  day,  it  is  divided,  presents  all  the  essential  and  distinctive 
characters  of  a  true  gland,  so  that  its  description  would  have  been 
more  correctly  given  under  the  general  heading  of  "  Glands." 

The  nerve  or  ganglionary  cells  present  essentially  the  same  structure 
as  all  other  glandular  cells,  and  are  doubtless  continually  passing  through 


390  THE     SOLIDS. 

the  same  phases  of  development  and  destruction  during  the  progress 
of  nutrition  and  secretion. 

The  secreting  or  glandular  cells  in  the  brain  and  spinal  marrow  are, 
for  the  most  part,  aggregated  into  distinct  masses,  the  term  ganglia 
being  equally  applicable  to  these  masses  as  it  is  to  those  existing  in 
connexion  with  the  nerves  of  the  sympathetic  system.     Henle  con- 
siders that  the  principal  development  of  new  cells  takes  place  on  the 
outer  surface  of  the  brain,  which  is  the  most  vascular  from  its  con- 
tiguity to  the  pia  mater,  and  that  the  more  mature  cells  are  gradually 
conveyed  inwards,  coming  thus  into  nearer  connexion  with  the  tubu- 
lar or  conducting  fibres,  the  disintegration  and  removal  of  the  older 
cells  determining  the  movement  of  the  cells  from  without  inwards. 
This  view,  as  applied  to  the  gray  matter  of  the  convolutions  of  the 
brain,  is  probably  correct,  and  is  to  some  extent  confirmed  by  an 
observation  which  I  made  several  months  since,  viz :  that  the  cortical 
substance  of  the  cerebellum  consists  of  two  distinct  portions,  separated 
by  a  well-defined  line,  perceptible  with  a  common  magnifying-glass : 
the  outer  portion  is  made  up  of  a  granular  base,  containing  but  few 
fully-developed  cells,  while  the  inner  portion  consists  almost  entirely 
of  completely-formed  cells.     The  distinct  separation  of  the  cortical 
or  secreting  matter  of  the  cerebellum  into  two  portions  is  very  remark- 
able, and  the  purpose  fulfilled  by  such  an  arrangement  wholly  obscure. 
Regeneration  of  Nervous  Matter. — The  regeneration  of  the  primi- 
tive nerve  tube  admits  of  proof,  both  by  experiment  and  direct  observ- 
ation.    The  experimental  proof  consists   in  the  simple  division  of 
nerves,  and  even  in  the  removal  of  portions  of  them :  the  parts  to 
which  the  nerve  is  distributed,  of  course  at  first,  lose  their  sensory 
and  motor  endowments:  these,  however,  after  a  variable  time,  are 
more  or  less  perfectly  recovered,  thus  completing  the  experimental 
proof.     The  direct  proof  is  derived  from  the  former :   the  recovery 
of  the  power  of  a  nerve  after  the  excision  of  a  portion  of  it,  argues 
strongly  the  fact  of  the  regeneration  of  the  nerve  tubes;  and  this 
result,  by  a  careful  microscopic  examination,  can  be  positively  demon- 
strated:  the  number  of  tubes  in  the  renewed  part  of  the  nerve  is 
stated,  however,  to  be  less  than  in  the  original  portions;  and  this  in 
part  explains  the  reason  of  the  restoration  of  the  functions  of  a  divided 
nerve  being  usually  but  imperfect.     Other  proofs  of  the  regeneration 
of  the  nerve  tubes  may  be  gathered  from  the  more  or  less  complete 
restoration  of  various  sensitive  and  motor  parts  of  the  body,  as  well 
as  from  the  reunion  of  parts  which  have  been  entirely  detached  from 
the  body,  as  the  nose,  the  top  of  the  finger,  &c. 


NERVES.  391 

With  respect  to  the  regeneration  of  the  glandular  element  of  the 
nervous  matter,  but  little  definite  or  microscopic  is  known:  from 
analogy,  however,  it  may  be  inferred,  that  like  other  cellular  structures, 
as  the  epidermis,  epithelium,  &c,  it  also  is  capable  of  a  more  or  less 
complete  reproduction. 

RESEARCHES    OF    M.    ROBIN. 

The  following  is  a  translation  of  an  abstract  made  by  the  author 
himself,  M.  C.  Robin,  of  a  paper  communicated  to  the  Royal  Academy 
of  Sciences  at  the  Seance  of  June  21st,  1847,  entitled  "Researches 
on  the  Two  Orders  of  Elementary  Nerve  Tubes,  and  the  Two  Orders 
of  Ganglionary  Globules  which  correspond  to  them." 

"  The  end  of  these  researches  is  to  show  that  the  ganglions  of  the 
spinal  nerves  and  of  the  great  sympathetic,  do  not  give  origin  to 
elementary  nerve  tubes,  as  many  modern  anatomists  admit,  as  Han- 
nover, Valentin,  Remak,  Bidder,  and  Volkmann,  &c,  &c. ;  but  that 
all  the  nerve  tubes  arise  exclusively  from  the  spinal  cord  and  the 
encephalon;  consequently  that  one  can  only  regard  these  ganglions 
as  special  little  nervous  centres,  performing,  with  respect  to  certain 
functions,  the  same  office  as  does  the  cerebro-spinal  centre  for  the 
other  functions.  These  reflections  naturally  occur  to  the  mind  when 
one  sees  the  cavity  of  the  tubes  or  elementary  nerve  fibres  given  off 
from  the  spinal  cord,  or  from  the  encephalon,  merge  into  the  cavity 
of  the  ganglionary  globules  at  one  of  their  poles,  and  reappear  at  the 
opposite  pole  of  the  globule  in  the  same  manner  that  they  entered. 

"Setting  out  from  a  globule  (cell),  these  nerve  tubes  proceed  to  lose 
themselves  in  the  organs.  Thus,  those  peculiar  cells,  the  agglomera- 
tion of  which  constitutes  the  ganglions  of  nerves,  are  no  other  than 
organs  which  are  interposed  between  the  origin  of  the  nerve  tube  and 
its  termination  at  a  determined  point  of  its  course,  and,  perhaps,  there 
is  more  than  one  upon  each  tube :  they  interrupt  it  in  its  course  to 
allow  it  once  more  to  reappear;  they  change  it,  they  modify  its 
structure  at  a  point  to  immediately  restore  it. 

"  The  authors  who  have  hitherto  written  upon  the  subject  have  not 
observed  the  entrance  and  exit  of  each  elementary  tube  at  the  two 
opposite  poles  of  each  globule,  but  only  the  one  or  the  other.  It  is 
this  circumstance  which  has  led  them  to  consider  each  of  these  gang- 
lionary globules  as  a  little  nervous  centre  of  origin  for  each  tube. 

"  There  is  yet  another  fact,  still  more  important  than  the  first,  which 
has  not  been  pointed  out  by  anatomists  who  have  studied  the  structure 
of  nerves. 


392  THE     SOLIDS. 

"They  have  all  described  but  one  order  of  globules:  there  are, 
nevertheless,  two  which  differ,  the  one  from  the  other,  in  numerous 
characters,  deduced  from  the  consideration  of  size,  form,  contents, 
walls,  &c.  One  of  these  orders  of  globules  is  always  in  connexion 
with  the  elementary  nerve  tubes  of  animal  life,  or  the  large  tubes,  &c. 
The  other  is  associated  especially  with  the  elementary  tubes  of  organic 
or  sympathetic  life,  or  with  the  small  tubes,  &c.  One  never  finds  the 
large  tubes  communicating  with  the  second  order  of  globules,  and 
reciprocally  the  small  tubes  are  never  in  connexion  with  the  poles  of 
the  globules  of  the  first  order. 

"It  follows,  from  these  facts,  that  one  can  no  longer  doubt  the 
existence  of  the  two  orders  (altogether  distinct)  of  elementary  nerve 
tubes  named  above,  which,  nevertheless,  some  authors  have  done 
recently.     (Kolliker.) 

"The  two  orders  of  globules,  and  of  the  corresponding  tubes,  exist 
in  the  posterior  or  sensitive  roots  of  the  nerves  of  the  spinal  cord,  but 
the  globules  do  not  exist  in  the  anterior  or  motor  roots. 

"They  exist  also  in  the  ganglions  of  the  encephalic  nerves  and  of 
the  great  sympathetic;  only  in  these  last  there  is  a  much  greater 
number  of  globules  and  of  slender  tubes,  than  of  globules  and  of  large 
tubes  (thirty  or  fifty  to  one),  more  or  less  according  to  the  ganglions. 
In  the  spinal  ganglions,  on  the  contrary,  there  are  about  four  or  five 
globules  and  large  tubes  to  one  of  the  other  kind. 

"These  facts  tend  to  confirm  the  observations  of  anatomists  who 
have  pointed  out  the  existence  of  the  two  orders  of  elementary  tubes 
in  the  nerves  of  animal  life,  and  those  of  the  great  sympathetic,  but 
with  predominance  of  the  large  tubes  in  the  first,  and  of  the  slender 
tubes  in  the  second;  notwithstanding  which,  no  one  of  them  has 
pointed  out  the  existence  and  the  difference  of  the  two  orders  of 
ganglionary  globules, 

"The  absence  of  ganglionary  globules  on  the  anterior  or  motor 
roots  of  the  spinal  nerves  anatomically  distinguishes  the  elementary 
tubes  of  motor  nerves  of  animal  life  from  those  of  the  sensitive  nerves. 
But  this  decisive  character  can  be  remarked  only  in  the  short  course 
of  the  roots  of  the  spinal  nerves  before  their  union  and  the  mixture  of 
their  tubes.  If  wishing  to  push  still  further  the  deductions  to  be  drawn 
from  the  preceding  facts,  we  demand  of  ourselves  what  functions 
should  be  attributed  to  the  ganglionary  globules,  we  should  answer, 
that  they  are  the  modifiers  of  the  action  which  takes  place  in  the 
sensitive  and  in  the  organic  nerves;  but  it  is  impossible  to  determine 
the  nature  of  this  modification. 


NERVES.  393 

"Since  the  ganglia  of  the  sympathetic  and  of  the  cereb#o-spinal 
nerves  enclose  the  same  ganglionary  globules,  and  the  same  element- 
ary tubes,  but  only  in  different  proportions,  we  see  that  we  cannot, 
with  Reil,  Bichat,  &c,  acknowledge  two  nervous  systems  independent 
of  each  other.  This  opinion  is  founded  on  the  communications  of 
the  great  sympathetic  with  the  spinal  nerves;  on  the  fact  of  nerves 
being  furnished  to  the  abdominal  diaphragm  of  birds,  exclusively  by 
the  great  sympathetic  (Sappey)  on  the  partial  and  successive  substi- 
tution of  sympathetic  nerves  for  spinal  and  encephalic  in  a  great 
many  vertebrata." 

The  above  highly  interesting  observations  of  M.  Robin  need  con- 
firmation, and  it  is  to  be  hoped  that  microscopic  anatomists  will  direct 
their  attention  to  the  subject.  In  the  many  examinations  which  I 
have  made  of  ganglia,  I  have  never  recognised  the  presence  of  two 
orders  of  ganglionary  cells,  nor  have  I  ever  perceived  any  attachment 
between  the  tubes  and  cells.  I  would  remark,  however,  that  I  have 
made  no  examination  of  the  ganglia  and  their  constituent  cells  since 
the  publication  of  the  researches  of  M.  Robin.  There  is  one  defect 
in  the  abstract  of  the  author,  of  which  we  have  given  a  somewhat 
literal  translation,  viz  :  that  the  distinctive  characters  of  the  two 
orders  of  ganglionary  cells  are  not  recited :  it  will  be  observed,  also, 
that  no  mention  is  made  of  their  occurrence  in  either  the  brain  or 
spinal  cord :  from  this  I  should  judge  that  M.  Robin  was  not  acquainted 
with  the  delicate  cells  described  by  me  in  Part  X.  of  this  work,  as 
existing  in  vast  numbers  in  the  white  substance  of  the  cerebrum,  cere- 
bellum, spinal  cord,  and  nerves  of  special  sense  wherever  this  occurs. 


394  THE     SOLIDS. 


NERVES. 

[The  examination  of  the  nerves  is  best  conducted  by  cutting  thin  slices 
with  a  very  sharp  scalpel,  or  flat-bladed  knife,  in  different  directions,  and 
subjecting  these  to  moderate  pressure,  having  previously  moistened  them  with 
water  or  with  serum.  Other  sections  may  be  gently  dissected  with  fine 
needles,  and  the  fibrillse  separated.  In  all  instances,  the  sooner  the  nerves 
are  examined  after  death,  the  more  readily  will  their  structure  be  determined. 

Hints  have  already  been  given  for  viewing  the  neurilemma,  the  white 
substance  of  Schwann,  and  the  "  axis  cylinder  "  of  Rosenthal  and  Purkinge, 
and  the  localities  pointed  out  in  which  the  Pacinian  bodies  are  found. 

Dr.  Stilling*  gives  the  following  instructions  for  examining  the  spinal 
cord : 

"I  place  a  fresh  spinal  cord,  and  medulla  oblongata,  as  they  are  taken  from  the 
body,  in  weak  spirit,  and  allow  them  to  remain  in  it  twenty-four  hours;  then  I  pour 
off  the  spirit,  and  place  fresh  but  stronger  spirit  on  the  parts,  which,  after  two  or 
three  days,  is  again  poured  off,  and  then  the  strongest  rectified  spirit  is  used;  the 
specimens  being  allowed  to  remain  in  it  from  four  to  eight  days,  acquire  by  degrees 
such  hardness  as  to  allow  of  the  finest  sections  being  made.  The  sections  being 
provided  (if  from  a  recent  cord),  are  then  to  be  extended  by  means  of  a  compres- 
sorium.  Low  powers  are  best  adapted  for  the  examination;  a  lens  of  two-inch 
focus  being  first  used,  and  then  others  of  higher  power." 

He  directs  the  sections  to  be  made  with  a  sharp  and  broad  razor,  the  sur- 
face of  which  must  be  kept  moistened  with  the  spirits  of  wine. 

Preparations  of  nerves  can  only  be  preserved  in  fluid ;  for  this  purpose, 
the  naphtha-water,  chromic  acid,  or  Goadby's  B-solution  may  be  employed.] 

*  Lancet,  Oct.  7th,  1843. 


ORGANS     OF     RESPIRATION.  395 


ART.  XX.  — ORGANS   OP   RESPIRATION. 

The  organs  of  respiration  seem  to  stand  alone  in  the  animal 
economy,  and  not  to  exhibit  any  strong  structural  relationship  or 
affinity  with  any  other  organ  or  organs  comprised  in  that  economy. 
In  their  position  and  general  form  they  bear  some  resemblance,  in 
the  mammalia  at  least,  to  glands :  this  resemblance,  however,  is  more 
apparent  than  real,  as  becomes  evident  from  the  single  consideration 
that  the  lungs  are  essentially  destitute  of  the  innumerable  granular 
cells  which  constitute  the  chief  bulk  of  true  glands,  and  form  their 
distinctive  and  essential  element.  In  a  strictly  natural  arrangement, 
the  lungs  would  be  more  properly  and  correctly  described  in  connexion 
with  the  circulatory  apparatus ;  for  essentially  they  are  vascular  organs, 
their  only  indispensable  constituent  being  blood-vessels,  so  situated, 
indeed,  as  to  admit  of  their  being  brought  continually  into  contact 
either  with  air,  or  with  water  impregnated  with  air. 

The  great  object  aimed  at  in  the  formation  of  the  lungs  of  mam- 
malia is  the  construction  of  organs  which  shall  occupy  but  little 
comparative  space,  and  which  shall  yet  present  a  greatly  extended 
surface,  throughout  which  the  blood  and  air  may  be  brought  into 
close  approximation.  We  shall  now  proceed  to  describe  the  manner 
in  which  this  purpose  is  accomplished. 

The  tissue  of  the  lungs  of  man  and  other  mammalia  may  be  divided 
into  two  systems  of  apparatus :  the  first  comprises  the  circulatory  or 
vascular  apparatus,  consisting  of  arteries  and  veins,  together  with  the 
plexuses  formed  by  the  union  of  the  capillaries  proceeding  from  both 
sets  of  vessels;  the  second  comprises  the  respiratory  or  aeriferous 
system,  which  includes  the  bronchial  tubes,  the  air  cells,  and  the 
ciliated  epithelium.  The  intimate  structure  of  the  lungs  will  be  best 
understood  by  an  examination  in  the  first  place  of  the  aeriferous 
apparatus. 

AERIFEROUS    APPARATUS. 

The  aeriferous  apparatus  of  the  lungs  consists  of  bronchial  tubes 
and  air  cells. 

Bronchial  Tubes. — The  bronchial  tubes  are  formed  of  cartilaginous 
rings  united  by  elastic  tissue:  the  rings,  however,  are  imperfect,  and 
are  only  present  in  the  larger  tubes,  as  those  of  the  first,  second,  and 
third  or  fourth  diameters:  in  the  smaller  tubes  they  are  absent,  these 
being  composed  entirely  of  a  nucleated  form  of  fibro-elastic  tissue: 


396 


THE     SOLIDS. 


they  divide  repeatedly  in  a  dichotomous  manner :  it  is  not  easy,  how- 
ever, to  determine  the  number  of  divisions  which  each  bronchial  tube 
undergoes  after  its  entrance  into  each  lobule ;  it  would  appear,  how- 
ever, that  the  intra-lobular  ramifications  are  less  numerous  than  the 
inter-lobular  branchings,  the  bulk  of  the  lobule  consisting  chiefly  of 
air  cells. 

The  bronchial  tubes  are  lined  throughout  by  mucous  membrane, 
which  is  invested  by  a  stratum  of  cylinder  ciliated  epithelium.  The 
smaller  bronchial  tubes  are  eminently  elastic  and  contractile,  by 
virtue  principally  of  the  elastic  tissue  of  which  they  are  chiefly 
formed.  This  elasticity  is  still  further  increased  in  the  case  of  the 
larger  tubes  by  the  presence  of  muscular  fibrillee  of  the  unstriped  kind. 

Air  Cells. — The  air  cells  are  minute  cavities  of  variable  size,  of  an 
angular  form,  not  dilated,  which  communicate  freely  with  each  other, 
and  the  parietes  of  which  are  formed  of  a  diaphanous,  tough,  highly 
elastic  and  delicately  fibrous  membrane,  which  contains  and  supports 
the  capillary  blood-vessels,  and  the  interior  of  which  is  lined  by  a  modi- 
fied mucous  membrane  also  invested  with  a  layer  of  ciliated  epithelium. 

From  this  description,  it  becomes  evident  that  the  air  cells  contain 
the  same  structural  elements  as  the  smaller  bronchial  tubes  themselves, 
and  that  they  therefore  differ  from  these  solely  in  form  and  arrange- 
ment, possessing  precisely  the  same  general  physical  properties,  being 
in  the  same  manner  highly  elastic,  a  property  mainly  dependent  upon 
the  abundance  of  fibro-elastic  tissue  present  in  the  lungs.  (See 
Plates  XLVII.  and  XLVIII.) 

That  the  air  cells  do  really  communicate  freely  with  each  other  (a 
fact  which  is  now  generally  admitted,  but  which  is  yet  denied  by 
Dr.  T.  Williams*)  may  be  satisfactorily  determined  in  many  ways. 
Thus,  it  is  by  no  means  difficult  to  see  the  circular  and  ever  patent 
openings  of  communication,  both  in  injected  and  uninfected  lungs ; 
again,  by  injection  with  size,  perfect  casts  of  the  cells  may  be 
obtained :  these  casts,  when  a  fragment  of  lung  is  torn  up  in  water, 
readily  escape,  by  which  means  the  variety  presented  by  the  cells  in 
form  and  magnitude  may  be  accurately  determined,  as  well  as  the 
shape  and  number  of  the  openings  of  communication.  (See  Plate 
XLVIII.  Jig.  2.)  Not  unfrequently  these  casts  are  more  or  less 
coated  with  the  epithelium  lining  the  cells,  as  also  represented  in  the 
figure  just  referred  to. 

*  "Essay  on  the  Structure  and  Functions  of  the  Lungs."  College  of  Surgeons 
London,  1842. 


ORGANS     OF     RESPIRATION.  397 

So  perfect  and  consistent  are  the  models  of  the  air  cells  procured 
in  this  way,  that  for  some  time  I  was  led  to  entertain  the  idea  that 
each  little  mass  of  size  was  really  enclosed  in  a  delicate  and  structure- 
less membrane,  which  I  conceived  to  be  the  true  air  cell  lining,  and  I 
have  scarcely  yet  been  able  to  discard  the  notion  altogether  from  my 
mind.  If  the  lung  be  injected  with  tallow,  we  do  not  procure  casts 
in  the  same  number  and  perfection,  because  the  tallow  adheres  closely 
to  the  sides  of  the  air  cells.  Sometimes  I  have  seen  casts  even  with- 
out injection;  but  the  occurrence  of  these  is  rare.  It  is,  therefore,  yet 
possible  that  I  have  not  been  deceived,  and  that  a  structureless  mem- 
brane does  really  line  the  air  cells,  a  modification  of  the  mucous  lining 
of  the  tubes,  the  "basement  membrane"  of  Bowman. 

It  would  appear  from  an  examination  of  these  casts,  that  the  num- 
ber of  openings  of  communication  varies  from  one  to  five;  usually, 
however,  but  one,  two,  or  three,  are  present. 

When  looking  attentively  at  these  casts,  covered  with  epithelial 
cells,  and  labouring  under  the  impression  that  they  were  really  distinct 
structures,  I  have  sometimes  perceived  cells  of  glandular  epithelium, 
one  much  larger  than  the  rest,  with  a  transparent  border ;  and  this  I 
fancied  was  a  fresh  cell  membrane  in  process  of  development. 

The  presence  of  epithelial  scales  in  the  air  cells  was  first  observed 
by  Mr.  Addison;*  but  that  gentleman  was  unable  10  determine 
whether  these  were  ciliated  or  not;  subsequently  Mr.  Raineyf 
advanced  the  statement  that  healthy  air  cells  contain  no  epithelium. 
In  sections  of  recent  lungs,  it  is  a  very  easy  matter  not  merely  to 
determine  the  existence  of  epithelium  in  the  air  cells,  but  also  the 
fact  of  its  cylinder  and  ciliated  form  and  character.  Circular  and 
oval  epithelial  cells  also  occur;  these  are  most  probably  ciliated  cells 
in  a  less  advanced  condition  of  development.  (See  Plate  XLVIII. 
fig.  3.  and  Plate  XLIX.  fig.  2.) 

It  has  been  stated  that  the  air  cells  vary  in  size.  This  is  the  case 
with  even  contiguous  cells,  as  may  be  seen  by  a  reference  to  the 
figures :  the  air  cells  in  the  lungs  of  an  adult  are  also  much  larger 
than  those  of  a  child. 

The  fact  of  the  epithelium  extending  from  the  bronchial  tubes  into 
the  air  cells,  would  seem  in  itself  to  imply  that  the  mucous  membrane 

*"  Observations  on  the  Anatomy  of  the  Lungs,"  by  Thomas  Addison,  M.  D.,  1841. 
— Transactions,  Medico- Chirurgic  Society. 

f  "On  the  Minute  Structure  of  the  Lungs,  and  on  the  Formation  of  Pulmonary 
Tubercle,"  by  George  Rainey. — Transactions,  Medico- Chirurgic  Society,  1845. 


398  THE     SOLIDS. 

also  lined  them,  at  least  in  a  modified  condition,  which  is  contrary  to 
the  opinion  expressed  by  Mr.  Rainey. 

VASCULAR    APPARATUS. 

The  vascular  apparatus  of  the  lungs  consists  of  arteries  and  veins: 
these  vessels,  after  numerous  ramifications  in  the  inter-lobular  spaces, 
unite  together  on  the  surface  of  the  air  cells,  through  the  medium  of 
a  beautiful  and  elaborate  system  of  plexuses,  each  air  cell  being 
furnished  with  its  own  separate  plexus. 

The  manner  in  which  the  vessels,  either  arteries  or  veins,  are  dis- 
tributed throughout  each  lobule  is  as  follows: — first,  large  branches, 
after  having  reached  the  lobule  through  the  inter-lobular  spaces, 
extend  over  an  area  of  several  cells  (see  Plate  XLVII.  fig.  2) ;  from 
these,  secondly,  a  number  of  smaller  vessels  proceed,  which  run  in 
the  spaces  between  the  cells,  forming  loops  around  them  (see  Plate 
XLVII.  fig.  3);  third  and  last,  from  these  inter-cellular  vessels  the 
capillaries  constituting  the  plexuses  are  given  off.  (See  Plate  XLIX. 
fig.  3.)  This  distribution  of  the  vessels  is  especially  evident  on  the 
pleural  surface  of  the  lung. 

From  the  preceding  description  it  does  not  appear  that  the  capillarv 
plexus  belonging  to  each  air  cell  is  compounded  of  both  venous  and 
arterial  capillaries,  but  that  in  most  cases  it  consists  entirely  of  capil- 
laries derived  exclusively  either  from  a  vein  or  an  artery. 

It  is  thus  evident  that  an  air  cell  with  its  investing  plexus  of  capil- 
laries contains  all  the  essential  constituents  of  an  entire  lung,  and 
therefore  that  each  air  cell  may  be  regarded  as  a  lung  in  miniature. 

It  is  well  known  that  it  is  frequently  a  matter  of  great  moment,  in 
a  medico  legal  respect,  to  discriminate  between  a  lung  naturally 
inflated  and  one  artificially  so:  the  test  proposed,  and  ordinarilv 
employed  and  relied  upon,  seems  to  me  to  be  unworthy  of  full  confi- 
dence. I  allude  to  the  hydrostatic  test:  it  is  stated  that,  by  firm 
pressure,  all  the  air  contained  in  a  portion  of  lung  artificially  inflated 
may  be  expressed,  so  that  it  will  sink  in  water;  but  that  this  cannot 
be  done  in  the  case  of  a  lung  naturally  inflated ;  a  portion  of  air  will 
always  remain  unexpressed  sufficient  to  keep  it  afloat.  I  see  no  good 
reason  for  this  constant  difference,  since  it  is  perfectly  certain  that  a 
lung  may  be  most  completely  and  entirely  injected  with  air  or  fluid, 
far  more  completely,  I  should  be  inclined  to  say,  than  occurs  with  air 
naturally  inspired,  except  perhaps  during  a  forced  inspiration.  Not- 
withstanding the  uncertainty  which  seems  to  me  to  be  attached  to 


ORGANS     OF     RESPIRATION.  399 

this  test,  I  yet  consider  that  by  a  careful  examination  of  the  condition 
of  the  blood  vessels  in  the  two  lungs,  the  question  may  in  most  cases 
be  satisfactorily  determined,  whether  has  the  lung  been  artificially  or 
naturally  extended  with  air? 

Previous  to  birth,  it  is  known  that  the  circulation  of  blood  through 
the  lungs  is  of  a  very  limited  character,  and  that  it  is  only  after  that 
period,  and  during  the  first  act  or  acts  of  respiration  that  the  great 
mass  of  vessels,  principally  capillaries,  become  carriers  of  blood. 

The  vessels,  then,  in  the  one  case,  viz:  before  respiration,  will  be 
almost  devoid  of  blood,  and,  in  the  other,  after  that  act,  replete  with 
that  fluid. 

Dependent  upon  this  difference  in  the  condition  of  the  vessels,  we 
shall  notice  certain  distinctive  features,  both  general  and  micro- 
scopical, in  the  case  of  the  artificially  and  the  naturally  inflated  lung. 
The  former,  after  inflation,  will  be  observed  to  collapse  to  nearly  its 
previous  size  on  the  escape  of  the  air :  it  will  present  a  pale  appear- 
ance, especially  evident  if  the  lung  be  cut  into,  and  when  examined 
with  a  lens,  it  will  be  seen  that  the  inter-spaces  between  the  lobules 
and  cells  are  pale,  not  being  occupied  with  red  vessels.  Now,  on  the 
other  hand,  the  latter  will  be  characterized  by  appearances  the  very 
reverse:  it,  after  inflation,  will  not  collapse  to  nearly  its  previous  size; 
it  will  be  somewhat  red,  and  the  intervals  between  the  lobules  and 
cells  will  be  seen  to  contain  red  vessels,  in  which,  as  well  as  in  the 
capillaries,  the  higher  powers  of  the  microscope  will  reveal  the  exist- 
ence of  red-blood  discs. 

PATHOLOGY. 

Now  that  the  normal  anatomy  of  the  lungs  is  well  understood,  the 
several  pathological  conditions  of  those  organs  admit  of  a  precise 
and  satisfactory  explanation.  The  principal  diseases  of  the  lungs, 
upon  the  exact  nature  and  seat  of  which  the  microscope  affords, 
directly  or  indirectly,  satisfactory  information,  are  Emphysema, 
Asthma,  Pulmonary  Apoplex)^,  Pneumonia,  and  Tubercle. 

Emphysema. — The  essential  pathological  and  microscopical  char- 
acters of  Emphysema  consist  in  an  enlargement  and  rupture  of  a 
greater  or  less  number  of  air  cells,  whereby  the  cavities  of  several 
distinct  cells  become  thrown  into  one,  with  sometimes  the  escape  of 
air  from  the  ruptured  air  cells  into  the  inter-lobular  cellular  tissue. 
When  the  air  cells  are  simply  dilated  and  ruptured,  without  any 
escape  of  air  from  them,  the  Emphysema  is  lobular ;  when,  on  the 


400  THE     SOLIDS. 

; 

contrary,  the  air  passes  from  the  cells  into  the  cellular  tissue,  which 
unites  the  lobules  to  each  other,  the  Emphysema  is  termed  inter-lobular. 
It  cannot  be  doubted  but  that  this  condition  of  the  lungs  interferes 
very  greatly  with  the  efficiency  of  these  organs ;  the  extent  of  surface 
over  which  the  air  and  blood  are  brought  into  contact  being  very 
considerably  diminished. 

Asthma. — The  microscope  has  revealed  the  fact  that  the  smaller 
bronchial  tubes  and  air  cells  are  principally  constituted  of  a  form  of 
elastic  tissue,  which,  possessing  marked  physical  properties,  is  yet,  to 
a  certain  extent,  under  the  control  of  the  nervous  system.  It  is  then 
the  irregular  action  and  contraction  of  this  tissue,  determined  partly 
by  physical  causes  and  partly  by  irregular  and  unequal  impressions 
arising  from  internal  causes  conveyed  to  this  tissue  by  the  nerves, 
which  occasion  and  account  for  the  distressing  and  peculiar  symptoms 
of  Asthma. 

Pulmonary  Apoplexy. — Pulmonary  apoplexy  is  simply  a  highly 
congested  condition  of  the  vessels,  which  are  principally  capillary. 
of  the  lungs.  A  congested  vessel  is  of  greater  diameter  than  an 
uncongested  one,  and,  therefore,  is  capable  of  containing,  and  really 
does  contain,  a  far  larger  quantity  of  blood  than  the  vessel  in  its 
normal  state.  There  are  many  stages  or  degrees  of  congestion  and 
of  pulmonary  apoplexy:  the  congestion  may  be  slight,  may  engage 
only  one  lung  or  a  portion  of  one;  the  dilatation  of  the  vessels  may 
be  but  trifling,  and  therefore  the  increased  quantity  of  blood  conveyed 
by  them  will  be  but  small;  or,  on  the  other  hand,  the  congestion  may 
be  very  great,  both  lungs  may  be  affected,  and  the  dilatation  of  the 
vessels  may  be  considerable;  the  quantity  of  blood  also  contained  in 
such  vessels  will  be  very  great.  In  cases  of  trivial  or  partial  conges- 
tion, a  slight  retardation  in  the  progress  of  the  blood  only  occurs ;  in 
the  more  severe  and  complete  cases,  the  blood  accumulates  in  the 
vessels  to  such  an  extent  as  that  the  circulation  is  totally  annihilated, 
death  being  the  necessary  result  of  such  a  condition  of  things. 

In  what  way  may  the  occurrence  of  this  congestion  be  explained, 
and  what  is  the  cause  of  the  cessation  of  the  circulation?  The  cap- 
illary vessels  of  the  lungs  are,  of  course,  incapable  of  coveying  beyond 
a  certain  quantity  of  blood :  any  causes,  therefore,  and  there  are  sev- 
eral, which  drive  in  upon  the  lungs  a  greater  amount  of  the  vital  fluid 
than  its  vessels  are  capable  of  circulating,  would  produce  congestion: 
the  first  effect  of  which  is  an  accumulation  of  blood  in  the  vessels; 
the  second,  an  enlargement  of  those  vessels,  the  coats  of  which  are 


ORGANS     OF     RESPIRATION.  401 

highly  elastic,  as  a  necessary  consequence  of  the  first;  third,  a  total 
cessation  of  the  circulation,  arising  from  the  rapid  aggregation  of  the 
blood  corpuscles  in  the  vessels.  The  various  degrees  of  congestion 
may  be  followed  out  with  the  microscope  in  the  most  satisfactory 
manner  in  the  tongue  of  the  frog,  or  in  the  web  of  the  feet  of  that 
creature.  Some  of  the  vessels  will  be  but  slightly  dilated;  other 
capillaries,  which  in  their  normal  state  are  capable  of  conveying  only 
a  single  row  of  corpuscles,  will  now  be  observed  to  contain  two  or 
three  rows;  in  others,  again,  the  blood  will  have  ceased  to  move 
altogether. 

These  several  changes  in  the  condition  of  the  blood  and  its  vessels 
during  congestion,  are  all  unaccompanied  by  structural  alterations,  by 
which  character  congestion  may  be  distinguished  from  inflammation. 

Pneumonia. — The  phenomena  of  congestion  precede  those  of  pneu- 
monia, of  which  indeed  it  may  be  considered  as  the  first  stage;  the 
second  stage  of  pneumonia,  consists  in  the  rupture  of  some  of  the 
capillary  vessels,  and  the  escape  of  a  portion  of  their  contents  (whence 
proceeds  the  characteristic  rust-coloured  expectoration),  as  well  as  the 
effusion  without  rupture  of  coagulable  lymph  through  the  walls  of  the 
vessels,  the  consolidation  of  which  in  the  air  cells  constitutes  the  con- 
dition of  the  lung  known  by  the  name  of  hepatization :  these  results 
are  probably  necessary  consequences  of  the  protracted  congestion : 
the  third  stage  of  pneumonia  is  attended  by  the  formation  and  excre- 
tion of  granular  cells  in  large  quantities,  imbedded  in  a  fibrinous  fluid : 
the  excreted  matter  may  be  either  mucus,  constituting  the  stage  of 
resolution,  or  it  may  be  pus,  when  the  pneumonia  is  said  to  terminate 
in  purulent  infiltration:  the  difference  between  the  two  excretions  is 
one  of  degree  rather  than  of  kind.  With  respect  to  the  nature  and 
origin  of  the  granular  corpuscles,  some  physiologists  will  have  it  that 
they  are  the  white  corpuscles  of  the  blood  escaped  from  the  vessels — 
an  opinion  completely  untenable:  they  doubtless  have  an  origin 
external  to  the  blood  vessels,  and  are  to  be  regarded  as  of  an  epithelial 
character,  representing  as  a  rule  the  peculiar  epithelium  of  the  surfaces 
or  parts  from  which  they  emanate. 

Tubercle. — The  earlier  microscopic  observers  approached  the 
investigation  of  tubercle,  especially  of  tubercle  in  the  lungs,  with  the 
expectation  of  finding  in  tubercular  matter  some  peculiar  element 
or  structure  which  should  account  for  the  fatality  and  apparent  malig- 
nity of  that  fearful  affection,  not  knowing  fully  the  true  structure  of 

the  organs  of  respiration,  and  therefore  not  perceiving  clearly  that  this 

26 


402  THE     SOLIDS. 

fatality  is  occasioned  rather  by  the  peculiar  structure  of  the  lungs 
themselves,  than  by  any  malignity  in  the  character  of  the  tuberculous 
formation.  Some  of  these  observers  have  even  fancied  that  they  have 
discovered  in  the  matter  of  tubercle  peculiar  and  characteristic  cells : 
it  is  now  scarcely  necessary  to  remark,  that  careful  and  extended 
microscopic  investigation  does  not  warrant  any  such  conclusion. 

One  of  the  most  accurate  views  with  which  I  am  acquainted 
respecting  the  nature  of  tubercle,  is  that  put  forth  by  Dr.  Addison:* 

"Tubercles  of  the  lungs,"  he  writes,  "are  composed  of  objects 
originating  from  blood  corpuscles,  which  have  been  arrested  in  their 
circulation  through  the  minute  vessels  of  the  structure  of  the  air  cells. 
So  long  as  this  retardation  is  confined  to  the  colourless  corpuscles, 
the  morbid  actions  which  ensue  are  strictly  those  of  an  abnormal 
nutrition,  and  various  forms  of  imperfect  and  degenerated  epithelium 
are  the  results ;  but  if  it  extend,  so  as  to  interfere  with  the  free  cir- 
culation of  the  red  corpuscles,  we  then  have  all  the  phenomena  of 
inflammation.  No  new  elementary  particles  are  formed  to  constitute 
a  tubercle,  and  although  from  the  insidious  nature  of  the  primary 
actions,  from  the  delicacy  of  the  structure,  and  the  important  charac- 
ter of  the  function  of  the  lungs,  the  treatment  of  tubercular  diseases 
must  always  be  attended  with  more  than  common  difficulties,  still 
there  is  every  reason  to  believe  that  they  are  susceptible  of  prevention 
and  cure,  especially  if  our  efforts  for  the  attainment  of  these  ends  be 
enforced  previous  to  the  appearance  of  a  cough,  which  is  not  a  con- 
comitant of  the  first  stages  of  tubercular  deposition  in  the  lungs." 

My  own  views  of  the  nature  of  tubercle  in  the  lungs  differ  in  one 
important  respect  from  those  of  Dr.  Addison ;  that  is,  with  reference 
to  the  precise  origin  of  the  imperfect  and  degenerated  epithelial  cells. 
Dr.  Addison  conceives  that  they  are  derived  immediately  from  the 
blood  itself,  while  I  consider  that  they  proceed  from  the  epithelium, 
which  has  been  described  as  lining  the  air  cells  themselves. 

A  tubercle,  then,  I  would  define  as  an  accumulation  of  epithelial 
scales,  the  imperfect  and  degenerate  representatives  of  the  true 
epithelial  cells  of  the  organ  or  part  in  which  the  tubercle  is  itself 
developed. 

*  "Experimental  Researches." — Transactions  of  Provincial  Medical  and  Surgical 
Association,  vol.  xi.  pp.  287,  288. 


ORGANS     OF     RESPIRATION.  403 

A  tubercle  of  the  lungs,  at  the  earliest  period  of  its  formation,  is 
exceedingly  small,  occupying  a  single  cell  only ;  when  this  cell  becomes 
filled  with  tubercular  matter,  a  rupture  of  its  membrane  occurs,  and 
thus  the  extension  of  the  tubercle  takes  place  from  cell  to  cell;  this 
extension  at  the  same  time  being  accompanied  by  a  destruction  and 
displacement  of  numerous  of  the  capillary  plexuses. 

After  the  above  description,  it  need  scarcely  be  observed  that 
tubercles  of  the  lungs  are  not  vascular. 


404  THE     SOLIDS. 

LUNGS. 

[The  presence  or  absence  of  epithelium  in  the  air-cells  of  the  lungs  is  a 
point  of  considerable  importance,  since  Dr.  Hassall  defines  tubercle  to  be  an 
accumulation  of  degenerate  epithelial  scales  in  the  air-cells;  a  definition 
that  would  possess  little  value  if  no  epithelium  was  there  present. 

Since  the  paper  by  Mr.  Rainey,  in  1845,  referred  to  in  the  text,  in  which 
he  contended  that  the  air-cells  were  not  furnished  with  epithelium,  the  same 
gentleman  has  extended  his  inquiries  to  the  lungs  of  inferior  animals,  and 
he  here  finds  in  several  instances  demonstrative  proof  of  the  non-existence 
of  epithelium.  His  paper*  thus  refers  to  the  opinion  of  those  who  still  main- 
tain "that  the  air-cells  are  lined  with  ciliated  epithelium." 

"The  demonstration  of  this  supposed  fact  has  been  attempted  by  filling  the  air- 
passages  with  tallow  or  size,  and  then  submitting  the  lung  thus  treated,  and  the  casts 
taken  from  the  air-cells,  to  examination  with  the  microscope.  I  may  observe  that 
all  the  ramifications  of  the  bronchial  tubes  have  a  very  complete  lining  of  ciliated 
epithelium,  which,  by  such  a  mode  of  preparation,  might  have  been  easily  detached, 
and  broken  up,  and  fragments  of  it  forced  into  the  air-cells;  hence,  such  a  mode  of 
procedure  seems  ill  calculated  to  determine  a  point  of  so  much  delicacy.  I  am  ready 
to  admit  that  corpuscles  of  various  kinds  may  occasionally  be  found  in  the  air-cells, 
but  these  have  not  the  most  remote  resemblance,  either  in  their  quantity  or  manner 
of  arrangement,  to  a  lining  of  epithelium,  especially  of  that  kind  which  is  called 
ciliated  epithelium.  Mr.  Addison  was  the  first  who  described  an  epithelium,  lining 
the  air-cells,  w7hich  he  states  to  be  in  the  form  of  round  nucleated  scales,  with  from 
one  to  fifteen  or  more  nuclei  observable  in  a  single  scale."  —  (Philosophical  Transac- 
tions, 1842,  Part  ii.  p.  162.) 

"  It  is  very  evident  from  this  description  that  Mr.  Addison  must  have  mistaken  the 
nuclei  in  the  coat  of  the  capillaries  for  an  epithelium,  an  error  which  it  is  very  easy 
to  commit,  in  examining  the  uninjected  lungs,  and  which  error  can  only  be  cor- 
rected by  comparing  the  lungs  uninjected  with  those  in  which  the  capillaries  have 
been  filled  with  injection.  I  have  frequently  seen  the  curve  formed  by  a  capillary 
projecting  beyond  the  free  border  of  the  pulmonary  membrane,  where  it  forms  a 
communication  with  an  adjoining  cell,  presenting  so  much  the  appearance  of  a  delicate 
epithelium,  that,  had  I  not  more  than  once  seen  a  vessel  in  a  similar  situation  in  the 
injected  lung,  I  might  have  mistaken  it  for  a  portion  of  epithelium,  lining  an  air-cell, 
and  considered  that  the  air-cells  have  a  lining,  if  not  of  ciliated,  yet  of  pavement 
epithelium,  as  some  anatomists  of  the  present  day  imagine." 

Mr.  Rainey  describes  the  bronchial  tubes  of  birds  to  be  lined  with  ciliated 
epithelium,  as  in  mammals.  The  air-cells  he  found  to  be  so  infinitely  small, 
that  it  is  impossible  for  them  to  be  lined  with  epithelium,  as  he  found  upon 
measurement  that  the  epithelial  scales  from  the  bronchus  of  a  pigeon  were 
_i_  of  an  inch  in  length,  and  -^^0   0I>  an  mcn  *n  breadth,  while  the  air- 

*  Medico-Chir.  Transactions,  1849. 


ORGANS     OF     RESPIRATION.  405 

cells,  or  air-spaces,  on  an  average,  measured   only  g^V o    °f  an  mcn  m 
diameter,  and  some  were  even  smaller. 

He  also  observed  that  in  the  kangaroo  many  of  the  air-cells  were  so 
minute,  that  a  single  cell  of  epithelium  would  have  entirely  filled  them,  and 
that  in  the  rat  and  mouse,  in  which  the  ciliated  epithelium  is  of  the  same 
size  as  in  man,  many  of  the  air-cells  were  too  small  to  receive  an  individual 
particle. 

Mr.  Rainey  considers  that  the  essential  and  only  true  organs  of  respira- 
tion, or  rather  of  the  aeration  of  the  blood,  are  the  pulmonary  capillaries, 
with  the  blood  in  them. 

Quain  and  Sharpey*  believe  the  air-cells  to  be  lined  with  delicate,  thin, 
transparent  mucous  membrane,  covered  with  a  stratum  of  squamous  epithe- 
lium. This  membrane,  by  a  doubling  inwards  of  itself,  forms  the  intervening 
septa. 

MANIPULATION. 

In  addition  to  the  methods  already  pointed  out  for  the  study  of  the  air- 
cells,  the  lung  may  be  artificially  inflated,  and  then  allowed  to  dry.  Thin 
sections  of  the  dried  lung  may  then  be  made,  and  the  size,  shape,  and  num- 
ber of  air-cells  readily  examined.  The  capillaries  can  only  be  viewed  by 
injecting  them ;  this  may  be  done  by  either  the  pulmonary  artery  or  vein. 
In  the  foetal  subject,  the  lungs,  with  the  rest  of  the  organs,  may  be  injected 
from  the  umbilical  vein. 

Rossignol's  experience  in  the  injecting  of  the  capillaries  of  the  lungs  is 
worth  here  recording.  He  found  that  injections  by  the  bronchial  arteries 
returned  by  both  the  pulmonary  and  bronchial  veins,  but  not  by  the 
pulmonary  artery. 

2dly.  That  the  injections  by  the  pulmonary  arteries  returned  entirely  by 
the  pulmonary  veins,  but  not  by  the  bronchial  arteries;  and  3dly,  that  by 
injecting  the  pulmonary  veins  it  was  easy  to  fill  all  the  other  vessels ;  viz : 
the  pulmonary  artery  and  bronchial  arteries  and  veins. 

Portions  of  injected  lung  are  best  preserved  in  fluid.  They  should  be 
mounted  in  cells,  just  deep  enough  to  allow  the  cover  to  be  applied  without 
coming  in  contact  with  the  object,  as  it  is  necessary  sometimes  to  change 
the  focus  of  the  object-glass  so  as  to  penetrate  to  the  bottom  of  an  air-cell ; 
the  fluid  may  be  either  spirit  and  water,  naphtha,  or  Goadby's  B-solution. 

Some  injected  lungs  show  well  when  mounted  in  the  dry  way. 

Plate  LXXIII.,  fig.  2,  shows  capillaries  and  air-cells  of  the  fcetal  lung. 
"  "         fig.  3,  do.  of  an  infant. 

"  "         fig.  4,  do.  of  an  adult. 

"  "         fig.  5,  Bronchial  laminae  of  an  eel.] 

*  "Quain's  Anatomy,"  by  Sharpey  and  Quain,  5th  edition,  p.  1153. 


406  THE     SOLIDS. 


ART.    XXI;  — GLANDS. 

Much  uncertainty  has  until  recently  prevailed  as  to  what  really 
constitutes  a  gland :  some  have  considered  those  only  as  true  glands 
which  are  furnished  with  distinct  openings  or  excretory  ducts;  others 
again  have  regarded  those  organs  only  as  glands  which  give  forth  a 
secretion:  the  former  view  of  a  gland  would  exclude  the  yascular 
glands  as  well  as  some  others,  and  the  latter,  although  it  would  include 
these,  and,  doubtless,  also  every  other  glandular  structure,  is  not  a 
sufficiently  obvious  or  structural  character,  the  secreted  product  of 
glands  in  many  cases  being  furnished  in  small  and  scarcely  apprecia- 
ble quantities,  and  which  again  are  immediately,  on  their  formation, 
absorbed,  in  some  cases,  into  the  circulation.  Again,  secretions  are 
supplied  by  parts  and  extended  surfaces  to  which,  although  they  are 
essentially  glandular,  the  term  gland  would  scarcely  be  applicable ;  of 
this  nature  are  the  free  surfaces  of  all  membranes  covered  by  epithe- 
lium, as  the  mucous,  serous,  synovial,  &c. 

We  have  still  then  to  inquire,  first,  what  are  the  essential  structural 
elements  of  which  all  glandular  organs  or  parts  are  constituted?  and, 
second,  what  is  the  exact  definition  to  be  given  of  a  gland? 

The  researches  of  modern  microscopists  have  indisputably  proved 
the  fact,  that  the  only  essential  elements  of  a  secreting  structure  are 
granular  cells  and  a  circulating  fluid,  the  secreted  product  being 
formed  out  of  the  latter  by  the  vital  endowments  resident  in  the  former. 

According  to  this  definition,  the  blood  itself  is  to  a  considerable 
extent  glandular,  inasmuch  as  it  contains  a  vast  number  of  granular 
cells  to  which  the  elaboration  of  the  fibrin  is,  in  all  probability,  due. 

Again,  the  free  surfaces  of  all  membranes  are  glandular;  the  epi- 
thelium covering  them  constituting  the  one  essential  glandular  element : 
the  varieties  in  the  size  and  form  of  the  cells  representing  this  epithe- 
lium have  been  already  described  in  a  former  chapter  of  this  work. 

Following  up  this  general  definition  of  glandular  structure,  a  gland 
may  be  defined  as  a  collection  or  aggregation  of  granular  cells  placed 
in  close  approximation  with  a  formative  fluid,  contained,  ordinarily, 
but  not  essentially,  in  the  blood-vessels. 

This  definition  of  a  gland  embraces  not  merely  those  glands  which 
are  provided  with  orifices  or  excretory  ducts,  but  also  those  which 


GLANDS.  407 

have  no  such  external  or  apparent  channels  of  excretion,  as  the 
vascular  and  other  glands. 

While  it  is  certain  that  secretion  takes  place  in  the  cavities  of  the 
granular  cells,  as  may  be  actually  shown  to  occur  in  the  hepatic, 
renal  and  sebaceous  cells,  there  is  much  reason  to  believe,  from  the 
rapid  and  continual  development  and  dissolution  of  successive  genera- 
tions of  cells,  as  especially  evident  in  the  case  of  those  of  the 
stomach  and  small  intestines,  that  this  secretion  is  liberated  in  many 
instances  only  by  the  dissolution  of  cells  themselves.  From  this  view 
of  the  relation  existing  between  the  secretion  and  the  cells,  it 
would  appear  that  the  secretive  process  is  accompanied  by  an 
endosmotic  action. 

In  the  case  of  fat  cells,  the  secretion  is  rarely  eliminated,  the 
secretive  process  is  exceedingly  slow,  and  the  oleaginous  matter  is 
stored  up  and  retained  within  the  cavities  of  the  cells  themselves,  the 
growth  of  the  cell  membrane  keeping  pace  with  the  increase  in  the 
amount  of  its  fatty  contents. 

The  idea  of  fluidity  is  almost  inseparably  connected  with  our 
notions  of  a  secretion ;  secretions,  however,  are  not  essentially  fluid, 
for  there  are  solid  secretions  as  well  as  fluid;  the  sebaceous  matter 
of  the  glands  of  the  prepuce  is  a  solid,  and  the  urine  of  many  ser- 
pents, as  the  boa,  is  also  stated  to  be  solid.  There  is  little  doubt, 
however,  but  that  most  and  perhaps  all  secretions  are  fluid  during  the 
act  of  their  formation,  and  that  the  solidity  acquired  by  certain  of 
them  occurs  after  their  perfection  and  elimination. 

In  a  strictly  systematic  arrangement  of  structures,  the  majority  of 
the  glands  might  well  be  described  in  connexion  with  the  internal 
and  external  integuments  of  the  body,  the  skin,  and  mucous  mem- 
brane, since  in  very  many  glands,  the  secreting  structure  is  contained 
within,  but  most  probably  not  developed  from  inverted  processes  of 
these  tissues.  Such  an  arrangement  of  the  glands,  although  a  very 
natural  one  as  far  as  it  goes,  would  yet  not  embrace  all  the  glands; 
the  vascular  and  some  others  would  be  excluded  from  it. 

The  proof  of  the  position  that  very  many  glands,  and  even  the 
most  complex  ones,  are  contained  in  offsets  of  the  various  modifica- 
tions of  mucous  membrane  and  outer  integument,  observers  have 
stated  to  be  derived  from  an  examination  of  these  organs  in  an 
embryonic  condition,  when  even,  it  has  been  affirmed,  the  most  elab- 
orate and  varied  of  them  may  be  seen  as  simple  follicles  or  sacs, 
springing  from  the  general  membrane  covering  the  skin  or  lining  the 
internal  cavities. 


408  THE     SOLIDS. 

It  would  appear,  however,  from  recent  and  trustworthy  observa- 
tions, that  the  principal  glandular  organs  of  the  body  have  each  a 
separate  development,  and  that  it  is  only  after  they  have  been  more 
or  less  completely  formed  that  they  become  attached  to  the  surface 
of  the  skin  or  mucous  membrane,  upon  which  their  secretions  are 
poured. 

Numerous  divisions  of  glands  have  been  proposed  by  different 
writers:  the  majority  of  these  do  not  require  any  special  notice: 
there  is  one,  however,  originating  with  Mr.  Goodsir,  which  would 
appear  to  be  ingenious  and  philosophical,  which  deserves  especial 
mention.  That  gentleman  divides  glands  into  two  types  or  classes; 
the  distinctions  existing  between  which  are  founded  upon  observations 
derived  from  the  study  of  the  early  development  of  these  organs. 

In  the  first  type  of  glandular  structure,  the  follicles  which  are  at 
first  distinct  from  the  excretory  duct,  but  which  subsequently  become 
united  with  it,  are  regarded  as  parent  cells,  the  granular  cells  con- 
tained within  them  being  secondary  formations,  which  are  continually 
in  process  of  development,  springing  from  a  germinal  spot  situated 
either  at  the  bottom  of  the  follicle,  if  this  be  short,  or  over  its  entire 
surface,  if  the  follicle  be  tubular :  in  this  class,  the  follicle  is  a 
permanent  structure. 

In  the  second  type,  the  follicle  is  also  a  parent  cell,  but  is  not  a 
permanent  structure;  and  having  attained  its  maturity,  it  bursts, 
discharges  the  secondary  cells  contained  within  it,  and  finally  shrivels 
up,  its  place  being  supplied  by  other  similarly  organized  cells. 

In  this  type,  but  one  gland  is  included — the  testis. 

The  arrangement  of  glands  proposed  below,  in  a  tabular  form, 
would  appear  to  be  one  of  the  least  objectionable,  as  well  as  the  most 
practical  for  purposes  of  description: 


CLASSIFICATION  OF     GLANDS. 

a    UNI-LOCULAR  GLANDS. 

Follicles.  Solitary  Glands. 

Stomach  Tubes.  Aggregated  Glands. 

b.   MULTI-LOCULAR   GLANDS. 

Sebaceous  Glands.  Mucous  Glands. 

Meibomian  Glands.  Labial  Glands. 


GLANDS.  409 

Glands  of  Hair  Follicles.  Buccal  Glands. 

Caruncula  Lachrymalis.  Gingival  Glands. 

Glands  of  Nipple.  Lingual  Glands. 

Glands  of  Prepuce.  Tonsellitic  Glands. 

Stomach  Glands. 

Tracheal  Glands. 

Vaginal  Glands. 

Uterine  Glands. 

c.  LOBULAR   GLANDS. 

Salivary  Glands.  Mammaiy  Glands. 

Pancreas.  Liver. 

Parotid  Glands.  Prostate  Gland. 

Submaxillary  Glands.  Cowper's  Glands. 
Lachrymal  Glands. 

d.  TUBULAR    GLANDS. 

Brunner's  Glands.  Ceruminous  Glands. 

Sudoriferous  Glands.  Kidneys. 

Axillary  Glands.  Testes. 

e.    GANGLIONARY    GLANDS. 

COMPOCyD,  SIMPLE. 

Brain  and  Cerebellum.  Ganglia  of  Encephalic  Nerves. 

Medulla  Oblongata  &  Spinal  Cord.  Ganglia  of  Sympathetic  Nerves. 

/.    ABSORBENT    GLANDS. 

Lacteal  Glands.  Lymphatic  Glands. 

g.   VASCULAR    GLANDS. 

Spleen.  Thyroid. 

Supra-renal  Capsules.  Pituitary  Body. 

Thymus.  Pineal  Gland. 

h.   GERM-BEARING    GLANDS. 

Ovaries. 

It  is  doubtful  whether  the  glands  admit  of  any  strictly  natural  and 
at  the  same  time  convenient  classification.  The  more  simple  glands 
pass  by  almost  insensible  gradations  into  the  more  complex,  thus 
leaving  but  few  salient  points  available  for  purposes  of  division.  The 
separation  of  the  multi-locular  from  the  lobular  glands  is  to  a  great 


410  THE     SOLIDS. 

extent  arbitrary,  and  is  adopted  simply  from  its  convenience.  Per- 
haps the  best  division  which  could  be  proposed  of  those  glands  which 
are  provided  with  excretory  ducts  or  openings,  is  into  follicular  and 
tubular  glands. 

It  is  very  probable  that  one  of  the  organs  introduced  into  the 
division  of  lobular  glands,  viz :  the  liver,  will  hereafter  have  to  be 
removed  from  that  division  and  placed  by  itself  near  to  the  vascular 
glands,  should  some  recent  researches  in  reference  to  the  termination 
of  the  biliary  ducts  be  confirmed. 

It  is  also  probable  that  further  research  will  disclose  the  fact  that 
certain  of  those  glands  arranged  as  mucous  glands  do  not  all  possess 
precisely  the  same  structure. 

UNI-LOCULAR  GLANDS. 

FOLLICLES. 

Crypts  and  follicles  are  inverted,  and  sometimes  tubular  prolonga- 
tions of  one  variety  of  mucous  membrane,  termed  compound,  and  to 
which  that  of  the  alimentary  canal,  the  gall-bladder,  the  uterus  and 
the  Fallopian  tubes  belong. 

In  the  stomach  and  in  the  large  intestines  these  follicles  are  so 
closely  set  in  the  membrane,  that,  from  the  mutual  compression  exer- 
cised upon  each  other,  they  assume  a  more  or  less  angular  figure ;  in 
the  small  intestines  there  are  fewer  follicles,  in  consequence  of  the 
great  number  of  villi  present  in  these,  and  they  are  not  angular,  but 
round.  These  follicles,  which,  in  the  small  intestines,  are  called  the 
follicles  of  Lieburkuhn,  are  met  with  under  two  very  different  condi- 
tions; in  each  of  which  they  present  a  very  distinct  appearance,  being 
in  the  one  case — that  is,  in  their  perfect  state — lined  by  epithelium, 
and  in  the  other  being  destitute  of  this  epithelium.  (See  Plate  L. 
figs.  1.  6.) 

The  epithelium  lining  the  follicles  of  the  alimentary  canal,  is  of  the 
same  kind  as  that  which  covers  the  inter-spaces  between  the  follicles, 
and  is  of  the  conoidal  variety.  It  lines  the  entire  follicle  with  a  beau- 
tifully regular  layer  of  united  epithelial  scales,  which  are  so  large  that 
they  nearly  fill  up  the  cavities  of  the  follicles,  a  small  circular  channel 
only  being  visible  in  each:  this  is  usually  occupied  by  the  mucus 
secreted  by  the  cells,  and  appears  at  the  mouth  of  each  follicle  as  a 
mere  depression,  surrounded  by  a  circle  of  radiating  epithelial  scales. 

To  see  the  epithelium  in  the  follicles  of  the  human  stomach,  and 
even  to  see  the  follicles  in  the  mucous  membrane  of  this  organ  at  all, 


GLANDS.  411 

requires  that  it  should  be  examined  immediately  after  death,  as  the 
lapse  of  a  few  hours  is  sufficient  to  allow  of  the  action  of  the  gastric 
juice  to  such  an  extent  as  to  dissolve  the  follicles  entirely. 

The  follicles  dip  into  the  thickness  of  the  mucous  membrane  to  a 
variable  extent  in  the  small  and  large  intestines;  their  extremities 
reach  nearly  to  the  sub-mucous  cellular  tissue,  and  in  the  lower  part 
of  the  rectum  they  are  much  elongated,  and  continued  for  some 
distance  into  the  sub-mucous  fibrous  tissue  between  the  mucous  and 
muscular  coats;  the  follicles  usually  terminate  in  rounded  and  some- 
times even  in  dilated  and  bifurcated  extremities!     (Plate  L.  j%.  7.) 

The  object  attained  by  these  innumerable  follicular  inversions  of 
the  mucous  membrane  of  the  stomach  and  intestines  is  obvious,  viz : 
a  greatly  extended  surface  for  secretion. 

The  mucus  with  which  the  intestinal  canal  is  so  abundantly  pro- 
vided, is  chiefly  secreted  by  the  epithelium  contained  in  these  follicles. 

Todd  and  Bowman  thus  describe  the  epithelium  of  the  stomach  cells 
in  the  "Physiological  Anatomy:"  ''They  [the  epithelial  particles] 
seem  to  lie  in  a  double  series,  the  deeper  being  in  course  of  develop- 
ment, while  the  more  superficial  is  in  course  of  decay.  It  has  appeared 
to  us  that  each  particle,  when  arrived  at  maturity,  has,  besides  the 
nucleus,  granular  contents  enclosed,  and  that  at  a  subsequent  period 
the  granular  contents  escape  at  the  free  extremity  by  a  dehiscence  or 
opening  of  the  wall,  at  that  part,  having  the  transparent  husk  with  its 
nucleus  subsisting  for  some  time  longer.  The  clear  structureless 
mucus,  which  is  almost  always  found  occupying  the  cells  and  cover- 
ing the  surface  of  the  membrane,  seems  to  be  the  altered  contents  of 
these  particles  after  their  escape ;  for  the  uniform  existence  of  a  minute 
cavity  in  the  centre  of  it,  when  it  fills  the  cells,  shows  that  it  has 
oozed  out  from  every  part  of  their  wTall  so  as  gradually  to  fill  them  up." 

The  ridges  or  spaces  between  the  follicles  of  the  stomach  and  large 
intestines  in  the  human  subject  are  occupied  with  a  plexus  of  vessels 
larger  than  capillaries  (see  Plate  U.fcg.  1) ;  these  are  situated  on  the 
deep  surface  of  the  basement  membrane,  while  the  epithelial  scales 
are  upon  its  superficial  surface :  in  the  cat,  and  many  other  animals, 
the  inter-follicular  spaces,  instead  of  being  occupied  by  a  plexus  of 
vessels,  contain  only  a  single  vessel,  which  freely  inosculates  with  the 
neighbouring  vessels,  thus  mapping  out  the  spaces  between  the  follicles 
into  somewhat  irregular  hexagons.     (See  Plate  LI.  fig.  2.) 


412  THE     SOLIDS 


STOMACH    TUBES. 


The  tubes  of  the  stomach  are  prolongations  of  the  basement  mucous 
membrane  lining  the  follicles  of  that  organ.     (See  Plate  h.figs.  3, 4,  5.) 

These  tubes  take  a  parallel  course,  end  in  irregularly-dilated  extrem- 
ities, are  arranged  in  sets  of  three,  four,  or  five  tubes,  each  of  which 
corresponds  with  a  follicle,  and  represents  the  number  of  tubes  which 
open  into  that  follicle:  it  is  only  however,  near  their  entrance  into 
the  follicles  that  they  are  thus  parcelled  out:  at  their  termination  they 
would  appear  to  be  independent  of  each  other,  and  to  be  separated  by 
equal  intervals,  as  represented  in  Plate  lu.Jig.  3. 

The  stomach  tubes,  unlike  the,  mucous  follicles,  are  filled  with 
spheroidal  or  glandular  epithelial  cells:  these  cells,  however,  do  not 
quite  fill  up  the  cavity  of  the  tubes,  but  leave  in  the  centre  of  each  a 
channel  or  canal,  along  which  the  fluid  secreted  by  the  cells  flows, 
until  at  last  it  reaches  the  follicle  into  which  it  is  poured. 

The  fluid  secreted  by  these  cells  is,  doubtless,  the  true  solvent  or 
gastric  fluid. 

The  tubes  I  find  to  exist  not  merely  in  the  stomach,  to  which  they 
are  generally  described  as  exclusively  belonging,  but  also  in  the  upper 
part  of  the  duodenum,  which  shows  that  in  the  human  subject  this 
portion  of  the  intestine  is  to  be  regarded  as  a  kind  of  second  stomach. 
I  have  observed  the  occurrence  of  these  tubes  more  than  once,  both 
in  the  duodenum  of  man  as  well  as  of  other  mammalia. 

The  fact  of  the  mucous  membrane  lining  the  duodenum  being 
frequently  dissolved  some  hours  after  death,  in  the  same  manner  as 
that  of  the  stomach,  would  in  "itself  lead  to  the  inference  that  these 
tubes  were  present  in  the  upper  part  of  that  division  of  the  aliment- 
ary canal. 

Messrs.  Todd  and  Bowman  figure  the  tubes  as  more  or  less 
branched  previous  to  their  entrance  into  the  follicles,  an  observation 
which  I  can  confirm:  these  gentlemen  also  thus  describe  a  modifica- 
tion of  the  follicles  and  tubes  near  to  the  pylorus:  "Here,  in  many  of 
the  lower  animals  which  we  have  examined — for  example,  in  the  dog, 
and  it  may  with  probability  be  inferred,  in  man  also — a  change  occurs 
in  a  very  gradual  manner,  but  evidently  of  an  important  kind.  The 
membrane  is  of  a  paler  tint,  and  its  cells  seem  not  to  terminate  at  once 
in  the  true  stomach  cells  already  described,  but  are  prolonged  into 
much  wider  cylindrical  tubes,  lined  with  the  same  columnar  epithelium, 
and  descending  nearly  or  altogether  to  the  deeper  surface  of  the  com- 


GLANDS.  413 

pound  membrane.  For  the  most  part,  these  prolongations  of  the 
celis — or,  as  we  shall  term  them,  pyloric  tubes — end,  at  length,  in  very 
short  and  diminutive  true  stomach  tubes;  but  we  have  likewise  found 
them  terminating  in  either  flask-shaped  or  undilated  extremities,  lined 
throughout  with  the  sub-columnar  variety  of  epithelium." 

The  stomach  tubes  are  each  surrounded  by  a  plexus  of  vessels. 

Sec  Plate  LXXIV.,  figs.  1 — i. 

FALLOPIAX    AND    L"TEREN"E    TUBES. 

Tubes  somewhat  similar  to  those  of  the  stomach  exist,  according  to 
the  observations  of  Mr.  Bowman,  in  the  mucous  membrane  of  the 
Fallopian  tubes  and  stomach. 

"The  lining  membrane  of  the  Fallopian  tubes,  as  well  as  that  of  the 
uterus,  is  of  a  compound  nature,  especially  during  gestation,  and  con- 
sists of  tubules  arranged  vertically  to  the  general  surface.  It  is  to  be 
observed  that  the  cilia  only  clothe  the  general  surface,  and  that  the 
epithelium  lining  the  tubules  is  spheroidal  or  intermediate  between 
that  and  the  prismatic.  It  is  a  form  of  the  glandular  variety,  and 
bears  no  cilia.* 

SOLITARY    GLANDS. 

The  solitary  glands  are  scattered  irregularly  over  nearly  the  whole 
surface  of  the  same  small  and  large  intestines ;  they  vary  consider- 
ably in  size — the  larger  glandulae  being  found  principally  in  the  lower 
portion  of  the  large  intestines,  and  admitting  of  easy  recognition 
without  the  aid  of  lenses;  while  the  smaller  glands,  situated  in  the 
lesser  bowel,  are  scarcely  visible,  except  in  states  of  disease,  when 
their  cavities  are  filled  with  secretion.  Plate  LI1.  fi&.  6,  is  a  drawing 
of  these  glands,  as  they  appeared  in  a  case  of  muco-enterite  in  one 
of  the  small  intestines,  while  Plate  LI.  Jig.  6,  is  a  representation  of 
them  as  found  in  the  larger  bowel  in  a  case  of  English  cholera 
in  a  child. 

These  glands  are  simple  sacs  or  cells,  filled  with  a  fibrinous  fluid, 
containing  imbedded  in  it  innumerable  spheroidal  and  granular  cells, 
somewhat  smaller  than  ordinary  mucous  corpuscles. 

I  have  observed  these  glandulae  both  with  and  without  central 
orifices;  these  have  been  more  frequently  absent  than  present;  hence 
it  is  very  probable  that  their  normal  condition  is  that  of  a  closed  cell, 
and  that  when  these  cavities  become  filled  with  secretion,  thev  rupture, 
and  thus  permit  their  contents  to  escape,  the  orifice  subsequently 
closing  up  again. 

*  Cyclopedia  of  Anatomy  and  Physiology,  Art.  "Mucous  Membrane,"  voL  iii. 


414  THE     SOLIDS. 

Not  unfrequently,  these  glands  in  certain  animals,  but  not  generally 
in  man,  are  observed  to  be  surrounded  by  a  circle  of  short  and  tubu- 
lar caeca;  these  by  some  observers  are  regarded  as  follicles  of 
Lieburkuhn,  and  it  is  uncertain  whether  their  bases  communicate 
with  the  cavities  of  the  glands  or  not,  but  it  is  generally  stated  not  to 
communicate  with  the  interior  of  the  glandules. 

The  distribution  of  the  vessels  around  these  glands  presents  nothing 
remarkable. 

AGGREGATED    GLANDS. 

The  aggregated,  agminated  or  Peyer's  glands,  are  present  in  the 
lower  portion  of  the  ilium  only. 

They  occur  in  patches  of  various  sizes,  each  of  which  is  made  up 
of  a  considerable  number  of  distinct  glandules,  having  much  the 
same  structure,  form  and  volume,  as  the  solitary  glands,  an  aggrega- 
tion of  which  they  may  be  considered  to  be.  These  patches  may  be 
readily  recognised  without  the  assistance  of  glasses. 

In  the  "glandulae  aggregatae,"  central  apertures  are  occasionally 
present,  and  they  are  not  unfrequently  surrounded  by  the  short 
tubular  caeca  already  spoken  of:  the  inter-spaces  between  the  gland- 
ulae in  the  human  subject  are  very  generally  covered  with  villi.  The 
size  and  limits  of  these  glands  may  be  best  determined  by  injection. 

When  examined  with  glasses,  as  they  lie  in  the  mucous  membrane 
in  situ,  they  appear  rounded  and  flat,  presenting  many  dark  spots, 
the  nature  of  which  is  not  understood :  when  viewed  sideways,  they 
are  seen  to  be  really  of  a  flask-shape,  the  narrow  extremity  of  the 
flask  being  turned  towards  the  surface  of  the  mucous  membrane. 
(Plate  111.  figs.  3,  4.) 

In  inflammation  of  the  mucous  membrane  of  the  ilium,  a  frequent 
concomitant  of  low  fevers,  these  glands  are  often  found  to  be  entirely 
eaten  away,  but  sometimes  they  are  only  so  far  eroded  as  to  present, 
in  place  of  closed  glands,  a  number  of  open  cells  or  follicles. 


MULTI-LOCULAE   GLANDS. 

SEBACEOUS    GLANDS. 

The  sebaceous  glands  are  very  generally  distributed  over  the 
surface  of  the  body,  probably  not  less  so  than  the  sudoriferous  glands, 
there  being  but  two  situations  in  which  they  are  stated  to  be  absent 


GLANDS.  415 

viz:  the  palms  of  the  hands  and  the  soles  of  the  feet.  On  all  other 
surfaces  of  the  body  the  two  kinds  of  glands  are  constantly  associated 
together,  the  sudoriferous  being  much  more  numerous  than  the  seba- 
ceous glands. 

They  are  found  especially  more  or  less  deeply  imbedded  in  those 
portions  of  integument  which  are  copiously  clothed  with  hair,  as  the 
scalp,  whiskers,  beard,  axilla,  pubis,  scrotum,  and  perineum.  They 
also  exist,  however,  in  abundance  in  certain  situations  not  usually 
invested  with  hair,  as  in  the  integument  of  the  forehead,  face,  and 
nose,  in  the  meatus  auditorius  externus  of  the  ear,  and  for  a  certain 
distance  up  the  anterior  openings  of  the  nares:  those  situated  around 
the  nipple  of  the  female  are  particularly  large,  while  those  of  the 
prepuce  are  not  merely  of  considerable  size,  but  yield  a  solid  and 
unctuous  secretion  of  a  peculiar  and  penetrating  odour. 

Those  glands  which  exist  in  situations  which  are  naturally  clothed 
with  hair,  always  open  into  the  hair  follicles;  while  those  present  in 
parts  not  furnished  with  such  a  covering,  yet  nevertheless  open  into 
follicles,  which,  although  from  the  absence  of  hairs  they  cannot  be 
called  hair  follicles,  must  yet  not  be  regarded  as  essentially  distinct 
from  hair  follicles,  since  they  in  some  cases  do  really  contain  hairs. 

As  there  are  varieties  of  sebaceous  matter,  so  are  there  sebaceous 
glands  which  differ  structurally  from  each  other;  thus,  the  cerumen 
glands  of  the  ear  present  a  conformation  typically  distinct  from  all 
other  sebaceous  glands,  belonging  to  the  tubular  type  of  glands,  with 
which  they  will  be  described. 

There  are  characters,  however,  in  the  possession  of  which  all 
sebaceous  glands  agree,  save,  perhaps,  the  cerumen  glands,  and  these 
are  in  the  semi-solid  nature  of  their  secretion  and  in  the  mode  of  its 
formation  and  elimination. 

The  secretion  of  the  sebaceous  glands,  like  other  secretions,  is 
formed  within  the  cells,  which  are  very  large,  and  in  which  it  exists 
in  the  form  of  little  spherical  and  shining  particles  of  various  sizes ; 
these  cells,  when  filled  with  the  secreted  matter,  are  thrown  off  with- 
out rupture  from  the  glands  in  which  they  have  been  formed,  probably 
by  the  development  of  fresh  cells  behind  them,  so  that  in  general,  the 
sebaceous  secretion  consists  of  an  aggregation  of  such  eliminated 
cells.  Some  few  of  the  cells,  however,  do  burst,  and  allow  of  the 
escape  of  their  contents. 

The  sebaceous  cells,  like  other  secreting  cells  in  an  early  stage  of 
development,  are  granular  and  nucleated. 


416  THE     SOLIDS. 

In  the  character  of  their  secretion,  the  sebaceous  glands  exhibit 
considerable  affinity  with  the  mammary  glands.  The  milk  globules, 
however,  are  formed  without  the  cells,  and  not  within  them,  as  is  the 
case  in  the  sebaceous  glands. 

The  sebaceous  glands,  exclusive  of  the  ceruminous,  manifest  con- 
siderable variety  in  size,  form,  and  arrangement.  They  may  be  thus 
arranged:  first,  the  Meibomian  glands;  second,  the  glands  of  the 
Hair  Follicles,  the  hairs  being  in  some  cases  present  in  the  follicles, 
and  in  others  absent  from  them;  third,  the  glands  of  the  Nipple; 
fourth,  the  glands  of  the  Prepuce:  and  fifth,  the  glands  of  Carunculee 
Lachry  males. 

Meibomian  Glands. 

The  Meibomian  glands  are  situated  on  the  inner  surface  of  the 
eyelids,  between  the  conjunctiva  and  the  tarsal  cartilages;  they  are 
of  an  elongated  form,  and  disposed  in  a  vertical  manner. 

The  number  of  these  glands  in  the  two  eyelids  is  usually  not  less 
than  forty;  in  one  instance  I  counted  eighteen  in  the  upper  eyelid, 
and  twenty-two  in  the  lower.  Their  general  form  and  arrangement 
differs  somewhat  in  the  two  eyelids;  thus,  in  the  lower,  they  are  of 
nearly  equal  length,  and  are  arranged  in  a  parallel  manner,  while  in 
the  upper  they  are  much  longer,  almost  as  long  again,  their  origins 
describing  an  arc ;  and  in  place  of  being  disposed  parallelly,  they 
radiate  from  each  other.  These  differences  depend  upon  the  corres- 
ponding differences  in  the  size  and  form  of  the  two  eyelids. 

Each  gland  consists  of  a  number  of  follicles  or  sacs  which  open 
into  a  central  canal,  which  pierces  the  conjunctival  membrane  at  the 
margin  of  the  tarsal  cartilages.  The  follicles  are  usually  filled  with 
cells,  which  may  be  seen  through  their  wTalls.  These  cells  present  a 
bright  and  shining  appearance  from  the  oily  nature  of  their  contents. 
(See  Plate  Ull.fig.  2.) 

Glands  of  Hair  Follicles. 

The  external  surfaces  of  the  body,  with  few  exceptions,  the  palms 
of  the  hands  and  soles  of  the  feet  being  the  principal  of  them,  are 
covered  with  the  hair  follicles,  which  are  placed  at  tolerably  regular 
distances  from  each  other,  and  the  apertures  of  which  are  visible 
even  without  the  aid  of  glasses. 

The  hairs  which  issue  from  these  follicles  differ  in  character  accord- 
ing to  their  situation:  those  of  the  scalp  being  long  and  fine;  those  of 


GLANDS.  417 

the  beard,  &c,  short  and  thick;  while  those  clothing  the  general  sur- 
face of  the  body  are  not  merely  short,  but  also  exceedingly  slender. 

In  certain  situations,  the  hair  follicles  are  frequently  without  hairs, 
as  on  many  parts  of  the  face;  this,  however,  is  the  exception  rather 
than  the  rule,  as  very  fine  hairs  are  generally  present  over  the  entire 
surface  of  the  face. 

It  is  into  these  hair  follicles  that  almost  all,  if  not  all,  sebaceous 
glands  open. 

The  sebaceous  glands  of  the  hair  follicles  consist  of  several  distinct 
cells  or  sacculi,  each  of  which  has  a  separate  excretory  duct ;  two  or 
more  of  these  ducts — there  being  sometimes  three,  four,  or  five — open 
into  one  common  duct,  which  last  opens  upon  the  sides  of  the  hair 
follicles:  there  are  usually  two,  but  sometimes  more  of  these  common 
ducts,  and  very  frequently  several  of  the  primary  excretory  tubes 
open  directly  into  the  hair  follicle.  The  ducts  are  large,  and  usually 
straight;  but  occasionally,  like  those  of  the  sudoriferous  glands,  they 
are  slightly  spiral.     (See  Plate  hill.  Jig.  1.  3.) 

Those  sacculi  which  open  into  the  hair  follicles  by  distinct  ducts 
are  to  be  regarded,  as  separate  glands.  In  the  hair  follicles  of  the 
scalp,  the  glands  are  usually  binary. 

The  glands  of  the  hair  follicles  are  not  confined  to  the  external 
surfaces  of  the  body,  but  are  continued  for  a  certain  distance  along 
several  of  the  outlets.  Thus,  they  occur  in  the  lower  part  of  the 
anterior  openings  of  the  nares,  in  the  meatus  auditorius  externus,  in 
the  palpebral  conjunctiva,  in  the  caruncula  lachrymalis,  in  the  vulva, 
and  on  the  interior  surface  of  the  prepuce. 

The  sebaceous  glands  vary  greatly  in  size,  being,  in  certain  situ- 
ations, much  larger  than  in  others,  as  in  the  eyelids,  ears,  nose,  around 
the  nipples,  especially  of  the  female,  and  on  the  inner  surface  of  the 
prepuce. 

The  cells  contained  within  the  ordinary  sebaceous  glands  differ,  in 
no  respect,  from  those  of  the  Meibomian  glands  already  described. 
It  is  in  the  hair  or  sebaceous  follicles  that  the  well-known  parasite,  the 
Steatozoon  Folliculorum,  whose  economy  has  been  so  well  described 
by  Mr.  Wilson,  is  found ;  it  being  placed  in  these  in  an  inverted  posi- 
tion, the  head  being  turned  inwards,  as  though  the  animalcule  had 
crept  into  the  follicles  from  without.  Many  of  the  follicles  frequently 
contain  more  than  one  parasite. 

27 


118  THE     SOLIDS. 

Caruncula  Lachrijmalis. 

The  caruncula  lachrymalis  is  usually  described  as  formed  of  a  single 
large  sebaceous  gland :  it  is  not  so,  however,  but  is  constituted  of  a 
considerable  quantity  of  mixed  fibrous  tissue  and  of  blood-vessels,  in 
the  midst  of  which  several,  usually  four  or  five,  distinct  sebaceous 
glands  are  imbedded. 

These  glands,  like  other  sebaceous  glands,  also  open  into  follicles, 
which  are  certainly  hair  follicles,  although,  in  the  human  subject,  they 
do  not  usually  contain  hairs.  That  they  are  really  hair  follicles,  how- 
ever, is  proved  by  the  fact  that  in  the  sheep,  minute  hairs  do  constantly 
issue  from  them. 

Glands  of  Nipple. 

The  sebaceous  glands  imbedded  in  the  integument  which  forms  the 
areola  around  the  nipple,  so  conspicuous  in  the  female,  differ  from 
other  sebaceous  glands  principally  in  their  larger  size,  which  allows 
of  their  being  readily  perceived  without  the  assistance  of  glasses. 

Glands  of  Prepuce. 

The  glands  of  the  prepuce  are  also  remarkable  for  their  large  size, 
as  well  as  for  the  peculiar  characters  of  the  secretion  which  they 
furnish:  one  of  these  being  its  semi-solid  consistence;  a  second,  its 
penetrating  and  remarkable  odour 

MUCOUS    GLANDS. 

The  great  agents  in  the  secretion  of  mucus  are  the  cells  contained 
in  the  follicles  with  which  all  compound  mucous  membranes  are 
furnished ;  there  is,  nevertheless,  a  description  of  gland  very  generally 
distributed,  differing  anatomically  from  the  follicles  also  called  mucous, 
and  which  is,  in  like  manner,  supposed  to  furnish  a  mucous  secretion. 
It  is,  however,  very  probable  that  as  there  are  structural  differences 
between  the  two,  so  are  there  differences  in  the  nature  of  the  secretion 
elaborated  by  them. 

Before  entering  into  a  description  of  the  mucous  glands,  it  will  not 
be  out  of  place  to  present  to  the  reader  the  results  of  some  additional 
researches  on  the  structure  of  mucous  membranes:  at  a  former  page 
of  this  work,  it  was  stated  that  mucous  membranes  may  be  divided 
into  simple  and  compound,  according  as  they  contain  follicular  invo- 
lutions, or  are  destitute  of  such  inverted  processes ;  and  that  the  com- 


GLANDS.  419 

pound  membranes  were  that  of  the  alimentary  canal  from  the  cardia 
downwards,  of  the  gall-bladder,  and  of  the  uterus  and  Fallopian  ubes, 
according-  to  Bowman.  Further  observations  have,  however,  shown 
me  that  on  the  one  side  the  mucous  membranes  of  he  mouth 
(including  that  which  lines  its  roof,  which  invests  the  tongue,  and 
which  covers  the  tonsils,  uvula,  and  epiglottis),  of  the  oesophagus 
down  to  the  cardia,  of  the  vagina  and  neck  of  the  uterus,  of  the  vesiculae 
seminales,  as  well  as  the  Schneiderian  membrane,  are  also  compound; 
while,  on  the  other,  the  mucous  membranes  of  the  Eustachian  tubes,  of 
the  trachea,  and  bronchial  tubes,  of  the  bladder,  and  of  the  unimpreg- 
nated  uterus,  and  Fallopian  tubes,  are  simple  mucous  membranes. 

The  follicles  of  the  mouth  are  somewhat  large,  scattered,  and  mostly 
simple ;  those  of  the  oesophagus  are  small,  and  not  unfrequently  divided 
into  branches  near  their  extremities;  the  follicles  of  the  vagina  resem- 
ble somewhat  those  of  the  oesophagus  ;  but  are  much  more  branched, 
very  many  of  the  follicles  terminating  in  several  offsets,  and  becoming, 
in  fact,  perfect  multi-locular  glands  :  the  follicles  of  the  Schneiderian 
membrane  are  the  largest  hitherto  noticed,  and  appear  to  be  simple 
inversions  of  the  membrane. 

It  has  been  stated  that  the  mucous  membrane  of  the  uterus  and 
Fallopian  tubes  is  simple;  in  which  respect  there  is  a  difference 
between  the  observations  of  the  author  and  those  of  Mr.  Bowman. 
Considerable  pains  have,  however,  been  taken  to  arrive  at  the  truth ; 
and  it  is  conceived  that  the  mucous  membrane  of  the  parts  cited 
affords  one  of  the  best  examples  which  could  be  given  of  a  simple  and 
delicate  mucous  membrane.  The  membrane  covering  the  lips  of  the 
uterus  and  lining  the  orifice  of  that  organ  is,  however,  like  that  of  the 
vagina,  follicular — the  follicles  in  the  latter  situation  being  particu- 
larly large;  and  it  is  these  follicles  which  yield  the  thick  and  tenacious 
mucus  which  usually  more  or  less  completely  plugs  up  the  uterine 
orifice. 

Mucous  glands  occur  in  very  many  and  different  localities,  in  sev- 
eral of  which  they  have  received  distinct  names,  taken  from  the  parts 
or  situations  in  which  they  have  been  found.  Thus,  we  have  labial, 
buccal,  tonsillitic,  lingual,  and  tracheal  glands ;  following  up  a  similar 
kind  of  nomenclature  for  these  glands,  we  might  add  to  this  list 
Eustachian,  palatine,  pharyngial,  and  bronchial  glands;  also,  glands 
of  the  uvula. 

In  the  roof  of  the  mouth  the  mucous  glands  are  very  numerous, 
forming  almost  one  continuous  glandular  layer,  provided  with  many 


420  THE     SOLIDS. 

orifices,  disposed  at  tolerably  regular  distances  from  each  other :  they 
are  also  numerous  in  the  tonsils,  but  much  less  so  in  the  uvula :  on 
the  dorsum  of  the  tongue,  mucous  glands  occur  but  very  sparingly, 
and  mostly  near  the  root  of  this  organ. 

There  are  some  few  situations  in  which  mucous  glands  have  been 
described  as  present,  in  which  they  would  appear  to  be  entirely  absent ; 
as  on  the  margins  of  the  gums,  where  they  have  been  called  gingival, 
in  the  uterus  and  vagina,  where  they  have  been  named  uterine  and 
vaginal  glands:  in  the  stomach,  also,  where  they  are  known  as  the 
lenticular  glands,  they  are  very  frequently  wanting. 

There  are  also  certain  glands  which  have  not  been  generally  placed 
in  the  category  of  mucous  glands,  which,  nevertheless,  are  really 
structurally  identical  with  them:  of  this  nature,  are  Brunner's  and 
Cowpers  glands. 

From  the  preceding  observation,  it  follows  that  Brunner's  and 
( -owper's  glands  should  be  described  with  the  other  mucous  glands : 
it  will,  however,  be  seen  hereafter  that  the  former  present  certain 
resemblances  to  the  tubular,  and  the  latter  to  the  lobular  glands. 

Messrs.  Todd  and  Bowman*  regard  the  mucous  glands  as  identical 
in  structure,  and  probably  in  function  also,  with  the  salivary  glands: 
that  they  are  not  salivary  glands,  however,  may  be  shown,  first,  by 
the  anatomical  differences  which  may  be  pointed  out  as  existing 
between  mucous  and  salivary  glands,  as  well  as,  secondly,  by  the 
fact  that  mucous  glands  occur  in  situations — as  in  the  trachea,  &c. — 
where  they  could  serve  no  purpose  as  salivary  glands.  Mucous 
glands  occur  in  two  forms:  a  simple  and  compound  form.  In  its 
simple  or  simplest  form,  a  mucous  gland  consists  of  a  single  duct,  in 
communication,  at  its  origin,  with  a  saccated  membrane,  each  saccu- 
lus  of  which  forms  an  imperfect  follicle.  In  its  compound  form,  it 
consists  of  several  ducts,  each  of  which,  at  its  origin,  is  in  like 
manner  in  connexion  with  a  bunch  of  incomplete  follicles. 

The  chief  anatomical  characters  which  distinguish  mucous  glands 
from  the  salivary,  to  which,  indeed,  they  bear  considerable  resem- 
blance, depend  upon  the  fact  that,  in  the  mucous  glands,  the  follicles 
are  incomplete;  that  is,  they  open  into  each  other,  and  into  a  common 
central  cavity,  from  which  the  single  efferent  duct  proceeds ;  while 
in  the  salivary  glands  each  follicle  is  a  distinct  body  of  a  rounded  or 
oval  form,  and  provided  with  a  small  primary  efferent  duct. 

Independent  of  the  important  differences  indicated  in  the  preceding 

*  Physiological  Anatomy,  p.  1 82. 


GLANDS.  421 

paragraph,  there  are  others,  viz:  the  larger  size  of  the  follicles  of  the 
mucous  glands,  and  the  coarser  and  firmer  texture  of  the  membrane 
which  constitutes  their  parietes. 

That  the  follicles  do  really  communicate  with  each  other,  is  proved 
by  the  numerous  circular  apertures  which  they  frequently  present, 
and  which  reminds  one  of  those  of  the  air-cells  of  the  lungs.  (Plate 
LIILj^.  4.) 

The  epithelium  contained  within  the  follicles  is  very  small,  the 
majority  of  the  cells  being  spherical. 

The  membrane  of  the  follicles  would  appear  to  be  fibrous,  and  is 
sufficiently  resisting  to  preserve  their  form  under  ordinary  pressure 
and  manipulation. 

BRUNNER'S    GLANDS. 

These  glands  have  been  already  referred  to  under  the  head  of 
mucous  glands,  with  which  they  are  structurally  identical. 

I  was  led,  for  a  short  time,  into  the  error  of  arranging  them  with 
the  tubular  glands,  in  consequence  of  observing  that  each  of  the 
larger  glands  of  Brunner  was  generally  furnished  with  several  tubu- 
lar ducts;  and  this  led  me  at  first  to  infer  that  they  were  formed 
entirely  upon  the  tubular  type,  which  is  not  the  case. 

In  those  instances  in  which  more  than  one  duct  proceeds  from 
what  appears  to  be  a  single  gland,  this  gland  is  not  really  simple,  but 
compound ;  that  is  to  say,  it  is  formed  of  several  clusters  of  follicles 
held  together  by  fibrous  tissue,  and  from  each  of  which  a  separate 
efferent  duct  proceeds. 

The  glands  of  Brunner  occur  only  in  the  duodenum,  and  occupy 
usually  the  upper  two-thirds  of  that  intestine:  their  number  and 
extent  of  distribution  vary,  however,  in  different  subjects. 

For  further  particulars,  see  the  description  of  the  Mucous  Glands. 

COWPER'S    GLANDS. 

Cowper's,  or  the  anti-prostatic,  glands  are,  as  already  mentioned, 
mucous  glands,  being  the  largest  examples  of  this  description  of  gland 
met  with  in  the  human  body. 

The  description  given  of  these  glands  by  authors  in  general,  their 
large  size  and  their  apparent  constitution  of  lobules,  were  the  reasons 
which  led  to  their  being  temporarily  classified  with  the  lobular  glands. 

The  description  given  of  the  mucous  glands  applies  in  every 
respect  to  these. 


422  THE     SOLIDS. 

A  knowledge  of  their  true  structure  and  relationship  explains  their 
use,  concerning  which  many  vague  conjectures  have  been  hazarded. 


LOBULAR   GLANDS. 

SALIVARY    GLANDS 

The  salivary  glands  include  the  parotid,  sub-maxillary,  and  lingual 
glands,  together  with  the  pancreas. 

These  several  glands  resemble  each  other  very  closely  in  structure, 
as  well  as  in  the  characters  of  the  secretions  furnished  by  them. 

The  salivary  glands  consist  of  lobes  and  lobules,  on  the  surface  of 
which  the  blood-vessels  ramify ;  the  lobes  are  made  up  of  the  lobules, 
and  the  lobules  themselves  consist  of  follicles  of  a  rounded  or  oval 
form,  and  each  of  which  is  furnished  with  a  minute  efferent  duct, 
which,  uniting  with  the  other  ducts  of  the  same  size,  forms  other 
larger  ducts,  and  these,  uniting  again  with  others  of  still  larger  calibre, 
at  length  form,  by  their  union,  the  main  excretory  tube  of  these 
organs.     (Plate  LIV.  figs.  1,  2,  3,  4,  5.) 

The  follicles  contain  numerous  minute  granular  cells  ;  and  those  of 
the  pancreas,  in  addition,  frequently  many  shining  globules  of  an 
oleaginous  character. 

Such  is  a  brief  description  of  the  salivary  glands  in  their  adult 
form :  in  their  embryonic  condition,  however,  they  do  not  consist  of 
lobes  and  lobules,  but  the  terminal  efferent  ducts  end  in  single  folli- 
cles, which  afterwards  become  multiplied,  until  at  length  clusters  of 
them  appear — the  incipient  lobules.     (Plate  LIV.  figs.  1,  2.) 

The  structure  of  these  glands  may  be  readily  followed  out  without 
the  aid  of  injection.* 

*  It  will  be  observed,  that  the  above  description  of  the  salivary  glands  agrees 
closely  with  that  ordinarily  given.  An  examination  of  these  glands,  instituted  since 
this  description  was  in  type,  has  convinced  me  that  they  approach  in  organization 
very  nearly  to  the  mucous  glands,  of  which  they  are  to  be  considered  as  a  variety. 
The  salivary  glands  differ  indeed  from  the  mucous  in  the  particulars  already  men- 
tioned, viz :  in  the  less  size  of  the  follicles,  and  in  their  more  complete  shape,  but 
nevertheless  are  formed  upon  a  similar  type  of  organization.  The  efferent  duct  with 
which  each  of  the  follicles  of  the  salivary  glands  is  said  to  be  furnished  is  so  short, 
that  it  in  very  many  instances  scarcely  deserves  the  name  of  such;  the  general 
arrangement  is  that  of  a  number  of  follicles,  almost  sessile,  clustering  around  the 
terminations  of  the  salivary  ducts. 


GLANDS.  423 


LACHRYMAL    GLANDS. 


These  glands  resemble  the  salivary  in  all  essential  structural  partic- 
ulars :  they  are,  however,  separated  from  them  in  consequence  of  the 
difference  in  the  character  of  the  secretion  which  they  furnish. 

MAMMARY    GLANDS. 

The  mammary  glands  do  not  require  any  lengthened  description, 
since  they  also  are  formed  upon  precisely  the  same  type  as  the  sali- 
vary and  lachrymal  glands. 

The  principal  structural  difference  has  reference  to  the  efferent 
ducts.  Each  salivary  gland  is  furnished  with  but  a  single  excretory 
duct,  while  to  each  mammary  gland  there  are  as  many  as  eight  or 
ten  ducts  which  open  on  the  apex  of  the  nipple:  the  ducts  of  the 
mammary  gland  are  also  remarkable  for  their  great  capacity,  for  it  is 
in  them  that  the  milk  principally  collects  when  it  is  allowed  to 
accumulate. 

When  the  follicles  of  a  mammary  gland  in  an  active  state  are 
examined,  vast  numbers  of  milk  globules,  of  various  sizes,  will  be  per- 
ceived within  them;  and  lying  in  the  midst  of  these,  the  small  gran- 
ular secreting  cells  will  be  seen:  these,  however,  do  not  contain  milk 
globules,  from  which  it  follows  that  the  milk  corpuscles  are  not  formed 
within  the  granular  cells,  but  external  to  them,  although  still  within 
the  cavity  of  the  follicles.     (Plate  ~LYV.Jigs.  3,  4,  5.) 

Mammary  glands  exist  in  the  human  male  as  well  as  female  breast, 
the  essential  structure  being  the  same  in  both,  as  proved  by  the  many 
cases  now  on  record,  in  which  infants  have  been  suckled  by  men. 

In  childhood  and  old  age  the  mammary  glands  consist  of  white 
fibrous  tissue,  in  the  midst  of  which  traces  only  of  the  follicles  can  be 
perceived. 

Numerous  lacteals  arise  from  the  neighbourhood  of  the  follicles;  by 
these,  the  more  watery  parts  of  the  milk  are  absorbed  when  this  is 
retained  for  any  length  of  time  within  the  breast,  and  in  this  way  the 
distension  of  that  organ  is  from  time  to  time  relieved. 

LIVER. 

The  liver  has  been  described  as  consisting,  like  the  other  glands  of 
the  lobular  form,  of  lobes,  lobules,  and  follicles  or  acini;  and,  indeed, 
in  some  of  the  lower  animals,  this  organ  has  such  a  constitution.  It 
has,  nevertheless,  recently  become   a  matter  of  very  great  doubt 


424  THE     SOLIDS. 

whether  in  the  Mammalia,  at  least,  the  same  type  or  organization 
prevails,  and  whether  the  structure  of  this  gland  in  this  class  of  animals 
is  not  of  a  totally  different  kind. 

The  mammalian  liver  consists  indeed  of  lobes  and  lobules,  but  the 
question  is  as  to  the  existence  of  the  follicles  or  acini  furnished  with 
their  efferent  ducts. 

In  the  adult  liver,  the  division  into  lobes,  even,  is  essentially  arbi- 
trary; so  that,  hi  fact,  it  is  of  lobules  alone  that  the  liver  is  entirely 
composed. 

Lobules. — The  lobules  of  the  liver  are  aggregations  or  masses  of 
granular  or  secreting  cells,  of  a  more  or  less  angular  form,  first  resting 
upon,  and  then  traversed  by,  branches  of  the  hepatic  vein,  and  enclosed 
on  all  sides  by  a  process  of  the  capsule  of  Glisson.  The  intervals 
separating  the  sides  of  two  lobules  from  each  other  are  called  inter- 
lobular fissures,  and  those  which  exist  where  three  or  more  lobules 
touch  each  other,  inter-lobular  spaces. 

These  lobules,  for  the  most  part,  are  perfectly  distinct  from  each 
other;  nevertheless,  not  unfrequently  two  of  them  are  more  or  less 
united  together,  as  is  seen  especially  on  the  surface  of  the  liver,  and 
in  preparations  in  which  the  hepatic  system  of  vessels  has  been 
injected.     (Plate  lAY.fig.  6.     Plate  LY.fig.  1.) 

The  lobules  of  the  liver  are  of  sufficient  size  to  be  easily  recognised 
with  the  unassisted  sight:  they  vary,  however,  in  dimensions,  not 
merely  in  the  liver  of  different  animals,  but  likewise  in  that  of  the 
same:  in  some  animals,  also,  as  in  the  rabbit  and  pig,  their  form,  as 
well  as  their  size,  may  be  clearly  defined;  and  in  these  they  are 
evidently  angular.     (Plate  LV.  fig.  1.) 

Such  is  a  brief  description  of  the  lobules  of  the  liver :  the  supposed 
follicles  or  acini  are  nothing  more  than  the  intervals  between  the 
meshes  of  the  capillary  vessels  which  ramify  through  the  substance  of 
the  lobules,  and  the  outlines  of  which  vessels  may  be  readily  followed, 
even  without  the  aid  of  injection,  their  course  being  indicated  by  a 
number  of  dark  lines. 

Mr.  Kiernan  supposed  that  the  acini  were  really  follicles,  and  that 
they  occupied  the  spaces  which  he  conceived  existed  between  the 
meshes  of  his  lobular  plexus  of  biliary  ducts. 

The  secreting  apparatus  of  the  liver  consists  not  only  of  lobules  and 
their  component  cells,  but  also  of  biliary  ducts  and  gall-bladder. 

Biliary  Ducts. — In  his  admirable  paper  on  the  liver,  inserted  in  the 
"Philosophical  Transactions"  for  1833,  Mr.  Kiernan  describes  the 


GLANDS.  425 

biliary  ducts  as  terminating  in  the  substance  of  the  lobules  in  a  com- 
plicated net- work  of  minute  biliary  vessels,  which  he  termed  the  lobular 
biliary  plexus.  Much  doubt,  however,  has  recently  been  cast  upon  the 
accuracy  of  this  description,  notwithstanding  that  it  has  received  the 
confirmatory  testimony  of  very  many  high  microscopical  authorities. 

The  first  observer  who,  I  believe,  expressed  doubts  of  the  existence 
of  a  lobular  biliary  plexus  was  Mr.  Bowman,  to  whose  numerous 
microscopical  researches  science  is  so  much  indebted. 

More  recently  still,  Dr.  Handfield  Jones,  in  a  paper  "On  the  Secre- 
tory Apparatus  of  the  Liver,"*  has  not  merely  expressed  the  same 
doubts,  but  has  entered  fully  into  the  reasons  on  which  his  opinion 
is  based. 

Dr.  Jones  founds  his  belief  of  the  non-existence  of  a  lobular  biliary 
plexus  upon  the  following  observations : 

"  First,  the  non-existence  of  basement  membrane  in  the  interior  of  the  lobules, 
which,  in  common  with  Mr.  Bowman,"  he  writes,  "I  have  been  unable  to  detect;  yet, 
were  this  simplest  constituent  of  a  duct  present,  it  could  hardly  escape  notice,  espe- 
cially as  hi  other  glands  it  admits  of  being  readily  demonstrated;  at  the  broken  margin 
of  a  lobule  it  may  be  well  seen  that  the  broken  extremities  of  the  linear  series  are 
quite  free,  and  exhibit  no  trace  of  any  containing  membrane.  Secondly,  if  the  margin 
of  a  lobule  be  carefully  examined,  where  it  forms  the  sides  of  a  fissure,  the  basement 
membrane  may  often  be  clearly  seen,  and  through  its  transparent  texture  the  terminal 
cells  of  the  linear  series  are  easily  distinguished,  resting  against  and  contained  by  it. 
Now,  were  the  membrane  inflected  to  form  lobular  ducts,  surely  some  indentation  or 
irregularity  would  be  visible  at  the  margin  of  the  lobule,  but  I  have  often  traced  the 
outline  carefully  without  observing  any  such.  A  third  proof  is  supplied  by  the  result 
of  some  experiments  which  I  made  on  rabbits.  I  tied  the  duct.  com.  choled.,  and 
shortly  after  death,  which  took  place  at  periods  varying  from  two  to  four  days,  I 
examined  their  livers:  these  organs  were  found  to  be  beset  on  the  surface  and 
throughout  their  substance  with  numerous  spots  of  deep  yellow  colour,  evidently 
produced  by  accumulation  of  bile;  a  section  of  these  spots,  examined  under  the 
microscope,  showed  that  they  were  very  partial,  never  extending  throughout  the 
whole  of  a  lobule,  but  frequently  situated  in  two  or  more  adjacent;  their  outline  was 
always  well  defined,  and  not  the  slightest  appearance  of  a  distended  plexus  of  ducts 
could  be  observed.  This  last  evidence  appears  to  me  conclusive.  I  can  hardly  con- 
ceive that,  if  any  plexus  of  anastomosing  ducts  existed,  the  accumulation  of  bile 
should  take  place  in  definite  spots,  and  those  not  always  situated  in  a  single  lobule, 
but  in  two  or  three  adjacent." 

Of  the  proofs  of  the  existence  of  a  lobular  biliary  plexus,  supposed 
to  be  derived  from  injection,  it  may  be  remarked,  that  these  are,  in  all 
probability,  fallacious,  the  injection  escaping  from  the  extremities  of 
the  biliary  ducts,  and  passing  into,  generally,  branches  of  the  portal 

*  Philosophical  Transactions,  1846. 


426  THE     SOLIDS. 

vein  from  which  it  extends  irregularly  into  the  lobular  capillary  plexus, 
and  it  is  this  plexus,  filled  with  injection  from  the  biliary  duct,  that 
Mr.  Kiernan,  it  appears  to  me,  took  for  a  lobular  biliary  plexus.  It 
still,  however,  must  be  regarded  as  a  singular  circumstance  that  the 
injection  should  so  generally  pass,  after  its  escape  from  the  ducts,  into 
blood-vessels,  in  place  of  becoming  extravasated  around  the  apertures 
of  the  ducts  from  which  the  injected  material  has  escaped. 

Presuming  it,  then,  to  be  concluded  that  there  is  no  lobular  biliary 
plexus,  let  us  next  inquire  in  what  manner  the  biliary  ducts  do  really 
terminate. 

From  the  further  researches  of  Dr.  Handheld  Jones,  contained  in 
a  recent  paper  communicated  to  the  Royal  Society,  and  entitled  "On 
the  Structure  and  Development  of  the  Liver,"  it  would  appear  that 
the  biliary  ducts  terminate  in  the  vertebrate  series  of  animals  in  the 
inter-lobular  fissures  and  spaces  in  closed  and  rounded  extremities. 
(Plate  LVII.  fig.  1.) 

If  a  branch  of  the  hepatic  duct  be  taken  up  with  the  forceps,  it  may, 
by  delicate  manipulation,  be  dissected  out  from  the  surrounding  paren- 
chymatous tissue.  A  branch  thus  prepared,  when  placed  under  the 
microscope,  will  be  seen  to  be  composed  of  numerous  ramified  biliary 
ducts  of  various  sizes :  the  extremities  of  a  majority  of  these  are  even 
broken  off;  but  several  are  evidently  entire,  and  these  are  rounded, 
as  represented  in  Plate  LVII.^g-.  1. 

These  ducts  are  not  simple  tubes,  formed  of  basement  membrane, 
but  are  lined  by  a  regular  layer  of  epithelial  scales :  these  serve  to 
secrete  the  mucus,  which  partly  occupies  them ;  and  their  presence 
accounts  for  the  great  difficulty  experienced  in  getting  the  injection 
to  flow  along  the  ducts. 

The  experiment  of  dissecting  out  a  branch  of  the  hepatic  duct  from 
the  parenchymatous  tissue  of  the  liver  is  most  readily  performed  in 
the  soft  livers  of  most  fish;  as  the  plaice,  sound,  &c;  but  it  may  be 
also  effected  in  the  livers  of  the  various  mammalian  animals. 

The  author  has  repeatedly  examined  branches  of  the  hepatic  duct 
thus  prepared,  and  his  own  independent  observations  fully  corroborate 
those  of  Dr.  Handheld  Jones,  to  whom  for  his  very  carefully  con- 
ducted inquiries  on  the  intimate  structure  of  the  liver,  physiological 
anatomists  are  much  indebted. 

The  mucous  membrane  lining  the  larger  hepatic  duct  is,  according 
to  the  observations  of  Mr.  Kiernan,  follicular. 

Secreting  Cells. — The  secreting  structure  of  the  liver,   as  of  all 


GLANDS.  427 

other  truly  glandular  organs,  is  cellular,  the  majority  of  the  cells  being 
perfect,  and  consequently  nucleated,  but  some  few  consisting  of  nuclei 
only,  the  most  essential  element  of  the  cell.  Each  cell  may  contain 
more  than  one  nucleus. 

These  cells  are  disposed  in  series,  which  radiate  from  the  centre  of 
each  lobule,  occupied  by  the  lobular  hepatic  vein :  the  radii  are  not 
formed  of  single  rows  of  cells  placed  simply  end  to  end,  but  the  cells 
frequently  partially  overlap  each  other.     (Plate  LIV.  fig.  6.) 

This  linear  disposition  of  the  cells  would  appear  to  be  determined 
by  the  radiated  arrangement  of  the  vessels  which  proceed  on  all  sides 
from  the  central  hepatic  vein. 

Dr.  Jones  considers  that  this  arrangement  of  the  cells  is  connected 
with  the  secretion  of  the  bile,  and  that  it  facilitates  the  transmission  of 
this  fluid  from  the  centre  to  the  circumference  of  the  lobules :  when 
it  has  reached  this,  it  is  discharged  into  the  inter-lobuiar  fissures  and 
spaces,  to  be  absorbed  into  the  ducts  by  an  endosmotic  action  deter- 
mined by  the  denser  mucoid  fluid  contained  within  them. 

Dr.  Handfield  Jones  has  also  observed  that  frequently  the  cells  are 
not  merely  disposed  in  linear  series,  but  that  they  likewise  coalesce 
with  each  other  by  their  opposed  margins,  whereby  the  cavities  of 
several  cells  are  made  to  communicate  with  each  other.  This  union 
of  the  cells  Dr.  Jones  considers  to  be  intended  to  facilitate  still  further 
the  transmission  of  the  bile  along  the  series  of  cells;  and  he  seems 
disposed  to  regard  it,  if  not  absolutely  essential  to  this  transmission, 
yet  as  of  very  general  occurrence.  There  can  be  no  question,  how- 
ever, but  that,  in  the  great  majority  of  cases,  the  bile  is  passed  from 
cell  to  cell,  independent  of  any  such  union :  this  is  proved  by  the  ex- 
ceeding rarity  of  the  occurrence  of  rows  of  cells  united  in  the  manner 
described  and  figured  by  Dr.  Jones. 

The  same  accurate  observer  considers  that  the  first  secretion  of 
bile  takes  place  in  the  most  central  cells  of  the  lobule,  and  that  this 
fluid  is  accumulated  in  the  greatest  quantity,  and  its  elaboration  per- 
fected, in  the  marginal  cells  of  the  lobule.  These  opinions  are  founded 
upon  the  following  experiments  and  observations  :  thin  sections  of  the 
liver  of  a  rabbit  being  examined,  the  ductus  communis  choledochus  of 
which  had  been  tied  twenty-four  hours  before  death,  it  was  manifest, 
in  almost  every  instance,  that  accumulation  of  bile  had  taken  place 
in  the  centres  of  the  lobules,  as  indicated  by  a  yellow  zone  of  some 
width  surrounding  the  intra-lobular  vein.  Now  this  case,  in  the 
opinion  of  Dr.  Jones,  presents  the  earliest  effect  of  interruption  to  the 


428  THE     SOLIDS. 

flow  of  the  secretion;  and  the  appearance  described  seems  to  point  out 
the  exact  spot  where  the  secretion  had  its  origin,  viz :  in  the  com- 
mencement of  the  rows  of  cells  surrounding  the  central  axis  of  the 
lobule,  as  represented  by  the  lobular  hepatic  vein :  again,  in  many 
livers,  a  remarkable  difference  may  be  observed  in  the  condition  of 
the  marginal  cells  and  those  placed  more  centrally;  while  the  latter 
have  appeared  of  their  usual  pale  or  light  yellow  colour,  and  have  con- 
tained but  one  or  two  minute  oil  globules,  the  former  have  presented 
a  darker  and  more  opaque  appearance,  arising  from  the  presence  of 
numerous  oil  globules. 

These  observations,  especially  when  considered  in  connexion  with 
the  mode  of  termination  of  the  bile  ducts,  render  it  almost  certain  that 
the  secreting  process  reaches  its  termination  near  the  margin  of  the 
lobule. 

Dr.  Jones  recognises  an  active  and  a  passive  condition  of  the  lobules 
of  the  liver,  and  thus  describes  the  differences  in  the  appearances  of 
the  margins  of  the  lobules  in  the  two  states: 

"  The  appearance  which  the  margin  of  a  lobule  presents  when  the  process  of  secre- 
tion has  been  proceeding  actively,  differs  much  from  that  which  is  observed  when  the 
lobule,  so  to  speak,  is  quiescent:  in  the  latter  ease,  as  I  have  described  it.  the  margin 
is  well  defined,  and  bounded  by  a  distinct  basement  membrane;  while  the  terminal 
cells  of  the  linear  series  contain  few  and  minute  oil  globules,  and  do  not  appear  to 
project  outwards  in  any  degree:  in  the  other  case,  the  margin  of  the  lobule  has  an 
opaque  cloudy  appearance  from  the  multitude  of  oil  globules.  Several  cells  are  seen 
projecting  into  the  cavity  of  the  duct,  giving  the  wall  occasionally  a  tuberculated 
appearance :  these  cells  contain  oil  globules,  and  their  wall  is  sometimes  so  extremely 
delicate  as  to  be  barely  perceptible  even  under  a  high  power.  Very  many  oil  globules 
are  also  seen,  which  lie  evenly  in  contact  with  the  sides  and  floor  of  the  duct:  it  is 
difficult  to  determine  whether  these  have  escaped  from  their  cells  or  not:  it  seems 
probable,  however,  that  they  are  for  the  most  part  free,  having  recently  been  liberated 
by  the  solution  of  their  cell  wall.  The  margin  of  a  lobule,  in  the  condition  now 
described,  presents  no  trace  of  basement  membrane;  the  cells  themselves  form  the 
wall  of  the  ducts,  preserving  still  the  general  outline:  it  seems,  therefore,  certain  that 
the  basement  membrane  is  only  a  temporary  structure,  which  disappears  when  the 
cells  are  actively  discharging  their  contents.  A  forcible  and  instructive  contrast  to 
the  above  condition  was  exhibited  by  a  liver  which  I  examined,  which  was  in  an 
advanced  state  of  fatty  degeneration:  in  this  the  linear  arrangement  of  the  cells  was 
lost;  they  lay  confusedly  together;  and  were  gorged  with  their  fatty  contents;  the 
margin  of  the  lobule,  far  from  exhibiting  any  tendency  to  discharge  the  retained  secre- 
tion, was  invested,  and,  as  it  were,  closely  bound  by  a  membrane,  not  of  the  delicate 
transparent  texture  of  the  basement  tissue,  but  much  more  opaque,  and  closely  resem- 
bling the  semi-fibrous  aspect  of  thin  layers  of  false  membrane." 


GLANDS.  429 

With  respect  to  the  dissolution  of  the  membrane  surrounding  the 
lobules  at  the  period  of  the  most  active  secretion  of  the  bile,  it  may  be 
remarked  that  it  is  a  matter  of  very  great  question  whether  this  is  either 
a  constant  and  necessary  occurrence,  or  even  a  very  frequent  one. 

Gail-Bladder. — The  gall-bladder  is  composed  of  an  outer,  strong, 
fibrous  tunic,  and  an  inner  mucous  one  :  this  latter  has  a  honeycomb 
arrangement,  and  is  of  the  follicular  type:  the  larger  meshes,  which 
are  plainly  visible  to  the  unaided  sight,  are  divided  by  ridges  of  mem- 
brane into  four  or  five  other  spaces  or  depressions  of  irregular  size  and 
form,  also  discernible  without  glasses :  and  these  again  are  still  further 
sub-divided  into  other  cells  very  numerous,  and  which  are  only  to  be 
seen  with  the  aid  of  the  miscroscope.  It  is  these  last  which  constitute 
the  follicles  of  the  mucous  membrane  of  the  gall-bladder,  which  differ, 
however,  greatly  from  the  ordinary  tubular  follicles  of  compound 
mucous  membranes,  being  simple  cells  or  depressions  formed  by  the 
plaited  and  ridged  arrangement  of  the  membrane  of  the  gall-bladder. 
The  follicles  in  the  hepatic  duct,  and  also  in  the  inner  tunic  of  the 
vesiculee  seminales,  would  appear  to  be  of  the  same  character. 

If  air  be  inserted,  by  means  of  the  blow-pipe,  beneath  the  mucous 
coat,  the  latter  will  be  thrown  up  into  lobes,  each  of  which  corresponds 
with  one  of  the  larger  honeycomb  cells:  this  fact  shows  that  the 
mucous  membrane  of  the  gall-bladder  is  bound  down  to  the  fibrous 
tissue  beneath,  principally  in  the  intervals  between  the  cellular  depres- 
sions alluded  to. 

Injection  thrown  into  the  ductus  communis  choledochus  very 
frequently  reaches  the  coats  of  the  gall-bladder :  this  fact  affords  an 
interesting  and  striking  proof  that  the  vessels  ordinarily  injected  from 
the  common  hepatic  duct  are  not  biliary,  for  it  is  generally  acknowl- 
edged that  biliary  ducts  do  not  exist  in  this  situation — a  conclusion 
to  which  one,  without  hesitation,  arrives,  on  reflecting  that  in  such 
a  situation  they  could  serve  no  possible  purpose. 

General  Remarks. — Should  the  foregoing  account  of  the  mode  of 
termination  of  the  biliary  ducts  be  correct,  of  which  scarcely  a  rea- 
sonable doubt  can  be  entertained,  it  is  evident  that  in  the  vertebrate 
class  of  animals,  at  least,  the  liver  is  not  of  the  follicular  type,  and 
that  in  them  this  organ  should  be  separated  from  those  glands  formed 
on  the  follicular  type.  In  the  fact  of  the  secretion  making  its  way 
into  closed  vessels,  the  liver  clearly  manifests  an  intimate  and  essential 
relationship  with  the  vascular  glands. 

The  liver,  then,  in  the  vertebrate  series,  is  the  only  exception  with 


430  THE    SOLIDS. 

which  we  are  at  present  acquainted,  of  an  organ  which,  being 
furnished  with  an  excretory  duct,  is  yet  not  formed  on  the  follicular 
plan  of  development. 

In  all  follicular  glands,  the  secreting  cells  are  situated  on  the  inter- 
nal surface  of  the  basement  membrane:  in  the  liver,  however,  they 
are  placed  upon  its  external  surface,  the  true  basement  membrane 
terminating  with  the  termination  of  the  biliary  vessels. 

Mr.  Bowman  regards  the  innumerable  series  of  secreting  cells  as 
representing  the  continuation  of  the  biliary  ducts,  and  a  rudimentary 
condition  of  which  he  considers  them  to  be;  in  the  same  manner  as 
linear  series  of  granular  cells  represent,  according  to  some  observers, 
the  rudimentary  form  of  other  vessels  and  tissues;  as,  for  example,  the 
muscular  fibre  and  the  primitive  nerve  tubule. 

Vascular  Apparatus. 

The  vascular  apparatus  of  the  liver  has  been  well  understood  since 
the  period  of  the  publication  of  Mr.  Kiernan's  Researches.  This 
apparatus  consists  of  hepatic  veins,  portal  vein,  and  hepatic  artery. 

Hepatic  Veins. — The  venae  cavae  hepaticae  commence  in  the  centre 
of  each  lobule  of  the  liver  by  a  plexus  of  capillaries,  which  penetrates 
it  in  all  directions;  these  uniting,  form  larger  vessels,  and  which,  again, 
join  together,  to  constitute  the  central  lobular  vein :  this,  escaping 
from  the  lobule  altogether,  becomes  what  has  been  termed  the  sub- 
lobular  vein,  and  it  next  unites  with  other  sub-lobular  veins  to  form 
the  main  branches  of  the  hepatic  veins.     (Plate  LV.  fig.  1,  2.) 

Portal  Veins. — The  portal  vein  is  mainly  formed  by  the  union  of 
the  inferior  and  superior  mesenteric  veins;  and  these,  again,  have 
their  origin  principally  in  the  confluence  of  the  capillary  vessels  of 
the  villi  of  the  small  intestines. 

The  portal  vein  enters  the  substance  of  the  liver  at  the  transverse 
fissure.  After  numerous  ramifications,  many  of  its  branches  are 
spread  over  the  outer  surface  of  the  lobules :  these  branches  are  called 
the  inter-lobular  veins:  from  these  branches  others  still  smaller  pro- 
ceed; these,  penetrating  the  substance  of  the  lobules,  break  up  into 
capillaries,  which  unite  with  the  capillaries  of  the  lobular  hepatic  veins, 
already  spoken  of;  and  it  is  the  capillaries  of  both  hepatic  and  portal 
veins,  thus  united,  that  constitute  the  lobular  capillary  plexus.  (Plate 
IN.  fig.  4;  Plate  L VI.  fig.  1.) 

The  lobular  plexus  may  be  completely  injected  either  from  the 
portal  or  hepatic  veins,  as  might  be  supposed  from  the  fact  of  its  being 


GLANDS 


431 


constituted  of  vessels  derived  from  both.  This  plexus,  however,  is  not 
always  fully  injected :  it  is  only  when  the  operation  of  injection  has 
been  very  successfully  performed  that  this  result  is  secured :  some- 
times, in  injecting  from  the  portal  vein,  the  injection  fills  only  those 
vessels  which  ramify  on  the  surface  of  the  lobules,  viz :  the  interlob- 
ular veins,  as  represented  in  Plate  IN.  fig.  4;  in  other  instances,  the 
injection  will  penetrate  further,  and  fill  that  portion  of  the  lobular 
plexus  which  is  formed  by  the  capillaries  which  belong  especially  to 
the  portal  vein;  in  this  case  a  zone  of  capillaries  surrounds  each  lob- 
ule, as  figured  in  Plate  LVI.  fig.  1.  In  others,  again,  the  injection 
will  fill  the  entire  lobular  plexus,  and  extend  even  to  the  central  lob- 
ular hepatic  vein  (Plate  LVI.  fig.  4);  in  this  latter  case,  the  entire 
section  of  the  liver  appears  but  a  mass  of  capillaries,  the  size  and  form 
of  the  lobules  being  indicated  merely  by  the  cut  extremities  of  the 
larger  lobular  and  inter-lobular  vessels. 

On  the  other  hand,  in  injecting  from  the  hepatic  veins,  the  injection 
may  reach  only  the  central  lobular  vein  and  its  principal  ramifications, 
as  shown  in  Plate  IN.  fig.  1 ;  or  it  may  fill  that  portion  of  the  lobular 
plexus  especially  formed  by  the  capillaries  of  the  hepatic  veins,  in 
which  case  each  lobule  will  appear  to  be  the  centre  of  a  separate 
injection  (Plate  IN.  fig.  2);  lastly,  the  entire  lobular  capillary  plexus 
is  sometimes  injected  from  the  hepatic  veins  in  the  same  manner  as 
from  the  portal  vein. 

In  those  instances  in  which  two  lobules  are  seen  to  be  united 
together,  the  vessels  are  also  observed  to  proceed  directly  from  one 
to  the  other;  this  communication  is  especially  evident  in  injections 
of  the  hepatic  veins.     (Plate  IN.  fig.  2.) 

The  form  of  the  portal  vein,  from  its  origin  in  the  villi  of  the  intes- 
tines to  its  termination  in  the  lobules  of  the  liver,  may  then  be  com- 
pared either  to  two  trees  joined  by  their  trunks,  or  to  a  single  uprooted 
tree.  The  preceding  account  renders  it  evident  that  it  is  from  the 
blood  contained  in  the  portal  vein  that  the  secretion  of  bile  takes  place. 

In  those  cases  in  which  the  blood-vessels  become  injected  from  the 
biliary  ducts,  it  is  usually  the  portal  system  which  receives  the  greater 
part  of  the  injection;  and  this  is  thrown  into  it  at  different  points 
irregularly,  so  that  there  are  no  definite  zones  of  capillaries  marking 
out  the  lobules ;  but  masses  of  capillaries  are  seen  here  and  there 
arranged  without  any  certain  order. 

Hepatic  Artery. — The  hepatic  artery  is  the  nutritious  vessel  of  the 
liver ;  it  supplies  the  vessels  of  the  hepatic  ducts,  the  vasa  vasorum, 
and  the  capsule  of  the  liver. 


432  THE     SOLIDS. 

It  is  distributed  principally,  however,  to  the  capsules  covering  the 
lobules,  and  to  the  general  capsular  investment  of  the  liver. 

Some  of  the  inter-lobular  or  lesser  capsular  branches  penetrate  the 
substance  of  the  lobules,  and  terminate  in  the  portal  capillaries  of 
the  lobular  plexus.     (See  Plate  LVI.  fig.  2.) 

The  outer  capsular  branches  are  remarkable  for  their  great  length, 
and  the  simple  manner  in  which  they  divide  and  sub-divide. 

The  hepatic  artery  does  not  anastomose  with  the  hepatic  vein. 

Pathology. 

The  pathology  of  the  liver  may  be  divided  into  two  sections, 
according  as  the  seat  of  the  disease  affects  its  secreting  or  vascular 
apparatus. 

Secreting  Apparatus. 

Two  abnormal  conditions  of  the  secreting  cells  of  the  liver  have 
been  noticed :  in  the  first,  biliary  engorgement,  the  cells  are  seen  to 
contain  a  greater  quantity  of  biliary  matter,  in  the  form  of  globules 
of  various  sizes,  than  ordinary;  in  the  second,  fatty  degeneration  of 
the  liver,  the  cells  are  laden  with  innumerable  globules  of  an  ole- 
aginous character;  this  condition  of  the  cells,  of  course,  impairs,  to 
a  very  great  extent,  their  secretory  powers.     (See  Plate  hVll.fig.  2.) 

Livers  thus  laden  with  oleaginous  particles  have  been  termed  fatty ; 
this  term,  although  expressive,  is  certainly  incorrect.  Fat  is  a  dis- 
tinctly organized  cellular  constituent  of  the  higher  forms  of  animal 
organization ;  and  each  true  fat  globule  is  a  perfect  cell,  constituted 
of  nucleus  and  cell  wall.  The  minute  globules  of  oil  existing  in  the 
cells  of  the  liver  and  of  some  other  glands,  especially  in  disease,  have 
none  of  the  attributes  of  cells;  they  are  merely  globular  collections 
of  an  oily  fluid,  similar  to  those  which  exist  in  the  cells  of  cartilages. 

It  is,  therefore,  evident  that  the  term  fatty,  applied  to  organs 
affected  in  the  manner  described,  is  scientifically  and  fundamentally 
improper:  the  appellation  of  oily  would  be  more  correct. 

The  truly  fatty  liver  and  kidney  do,  certainly,  occasionally  present 
themselves  to  our  notice;  in  these,  there  is  an  accumulation  of  true 
fat  cells,  not,  indeed,  within  the  epithelial  particles,  but  in  the  inter- 
spaces between  the  lobules  and  tubules,  and  also  beneath  the  capsules 
to  a  less  degree. 

The  microscopic  characters  of  the  disease  called  cirrhosis  do  not 
appear  to  have  been  as  yet  satisfactorily  determined. 


GLANDS.  433 

Vascular  Apparatus. 

A  knowledge  of  the  distribution  of  the  blood-vessels  in  the  lobules 
of  the  liver,  has  enabled  the  pathologist  to  explain  satisfactorily- 
various  abnormal  appearances  connected  with  its  vascular  apparatus. 

The  lobules  of  the  liver  of  persons  or  animals  that  have  bled  to 
death,  or  that  have  died  in  an  exceedingly  anaemic  condition  resulting 
from  disease,  present  a  pale  and  ex-sanguine  appearance,  arising  from 
the  small  quantity  of  blood  contained  within  the  blood-vessels. 

A  second  very  common  appearance  of  the  lobules  of  the  liver, 
after  death,  is  that  in  which  they  are  red  in  the  centre,  and  pale 
around  the  margin.  This  condition  arises  from  the  presence,  in  the 
venous  hepatic  vessels,  of  a  considerable  quantity  of  blood,  the  portal 
vessels  being  at  the  same  time  almost  destitute  of  this  fluid;  it  has 
been  called  by  Mr.  Kiernan  the  first  stage  of  hepatic  venous  conges- 
tion, and  is  said  to  be  due  to  the  continuance  of  capillary  action  in 
the  vessels  after  the  general  circulation  has  ceased. 

In  the  second  stage  of  hepatic  venous  congestion,  not  merely  the 
centres  of  the  lobules  are  red,  but  also  the  portal  plexus  in  parts;  the 
parts  of  the  lobules  which  are  most  free  from  congestion  are  those 
surrounding  the  inter-lobular  spaces;  so  that  the  non-congested  por- 
tions appear  in  the  form  of  isolated  and  irregular  patches,  in  the  midst 
of  which  are  situated  the  inter-lobular  fissures  and  spaces.  The 
second  stage  of  hepatic  venous  congestion  commonly  attends  disease 
of  the  heai't  and  other  disorders  in  which  there  is  an  impediment  to 
the  venous  circulation,  and  it  also  gives  rise,  in  combination  with 
accumulation  of  bile  in  the  secreting  cells,  to  those  various  appear- 
ances which  characterize  the  nutmeg  or  dram-drinker's  liver. 

A  third  form  of  venous  congestion  is  that  which  affects  the  portal 
veins  alone;  in  this  the  margins  of  the  lobules  are  red,  while  their 
centres  are  pale;  it  is  the  very  reverse  condition  to  hepatic  venous  con- 
gestion in  its  first  stage,  and  has  been  distinguished  by  Mr.  Kiernan 
by  the  name  of  portal  venous  congestion.  This  form  of  congestion 
is  rare,  and  has  hitherto  been  noticed  to  occur  in  children  only. 

The  fluid  of  the  liver,  the  bile,  has  already  been  described  in  this 
work;  in  addition  to  the  epithelial  scales  derived  from  the  mucous 
membrane  lining  the  gall-bladder,  the  bile  frequently  contains,  when 
inspissated,  concrete  masses  of  biliary  matter,  which  have  been  mis- 
taken for  true  cells ;  also,  crystals  of  cholesterine,  gall-stones,  and  the 
parasite  called  the  fluke  with  its  ova. 

28 


434  THE     SOLIDS. 

Hydatids  are  frequently  developed  in  the  substance  of  the  liver; 
these  often  attain  a  very  large  size.* 

Development  of  the  Liver. 

"With  respect  to  the  development  of  the  liver,  the  authorf  considers  the  opinion 
of  Reichart  to  he  decidedly  the  correct  one,  namely,  that  its  formation  commences 
by  a  cellular  growth  from  the  germinal  membrane,  independently  of  any  protrusion 
of  the  intestinal  canal.  On  the  morning  of  the  fifth  day,  the  oesophagus  and  stomach 
are  clearly  discernible,  the  liver  lying  between  the  heart,  which  is  in  the  front,  and 
the  stomach,  which  is  behind ;  it  is  manifestly  a  parenchymal  mass,  and  its  border  is 
quite  distinct  and  separate  from  the  digestive  canal  at  this  period ;  the  vitelline  duct 
is  wide,  it  does  not  open  into  the  abdominal  cavity,  but  its  canal  is  continued  into  an 
anterior  and  posterior  division,  which  are  tubes  of  homogeneous  membrane,  filled, 
like  the  duct,  with  opaque  oily  contents ;  the  anterior  one  runs  forwards,  and  forms 
behind  the  liver  a  terminal  expanded  cavity,  from  which  then  passes  one  offset,  which 
gradually  dilating  opens  into  the  stomach;  a  second,  which  runs  in  a  direction 
upwards  and  backwards,  and  forms  apparently  a  caecal  prolongation;  and  a  third  and 
fourth,  which  are  of  smaller  size,  arise  from  the  anterior  part  of  the  cavity  and  run 
to  the  liver,  though  they  cannot  be  seen  to  ramify  in  its  substance;"  at  a  somewhat 
later  period,  these  offsets  waste  away,  excepting  the  one  which  is  continued  into  the 
stomach,  and  then  the  mass  of  the  liver  is  completely  free  and  unconnected  with 
any  part  of  the  intestine.  As  the  vitelline  duct  contracts,  the  anterior  and  posterior 
prolongations  of  it  become  fairly  continuous,  and  form  a  loop  of  intestine,  the 
posterior  division  being  evidently  destined  to  form  the  cloaca  and  lower  part  of  the 
canal.  The  final  development  of  the  hepatic  duct  takes  place  about  the  ninth  day, 
by  a  growth  proceeding  from  the  liver  itself,  and  consisting  of  exactly  similar  mate- 
rial ;  this  growth  extends  towards  the  lower  part  of  the  loop  of  the  duodenum, 
which  is  now  distinct,  and  appears  to  blend  with  the  coats  of  the  intestine;  around 
it,  at  its  lower  part,  the  structure  of  the  pancreas  is  seen  to  be  in  process  of  forma- 
tion. The  further  process  of  development  of  the  hepatic  duct  will,  the  author  thinks, 
require  to  be  carefully  examined;  but  the  details  he  has  given  in  this  paper  have 
satisfied  him  of  the  correctness  of  the  statement  that  the  structure  of  the  liver  is 
essentially  parenchymal." 

*  On  one  occasion  I  noticed  the  liver  to  be  thickly  studded  throughout  with 
numerous  cysts,  the  largest  of  about  the  twelfth  or  eighth  of  an  inch  in  diameter. 
These  cysts  contained  a  gaseous  fluid  only ;  the  secreting  cells  included  a  greater 
quantity  of  oil  than  natural. 

f  Dr.  Handfield  Jones,  Abstract  of  Paper  in  Philosophical  Magazine,  September, 
1847. 


GLANDS.  435 


LITER, 


[For  a  very  accurate  account  of  the  minute  structure  of  the  liver,  with 
excellent  drawings,  the  reader  is  referred  to  a  paper  "on  the  Comparative 
Structure  of  the  Liver,"  by  Dr.  Jos.  Leidy,  of  Philadelphia,  and  published  in 
vol.  xv.  (new  series)  of  American  Journal  of  Medical  Sciences,  pp.  13-23. 

Dr.  Leidy's  researches  are  confirmatory  of  the  views  of  Dr.  Kiernan,  as 
laid  down  in  the  paper  referred  to  in  the  text. 

Appended  to  Dr.  Leidy's  paper,  will  be  found  a  table  containing  the 
measurements  of  the  secretory  cells  of  the  liver  in  several  of  the  different 
orders  of  animals. 

The  minute  structure  of  the  liver  should  be  studied  in  both  the  recent 
state,  and  after  injection ;  the  method  in  the  recent  state  is  the  same  as 
already  pointed  out  for  other  organs — thin  sections  in  different  directions, 
dissected  with  needles  under  water,  and  viewed  with  low  powers ;  others 
may  be  compressed,  and  treated  with  acetic  acid,  whereby  the  nuclei  of 
the  secretory  cells  are  readily  brought  into  view. 

The  arrangement  of  vessels  is  of  course  best  seen  after  injection.  Any 
one  particular  order  of  vessels  may  be  filled,  or  the  four  orders  may  be 
injected  with  different  colours.  When  this  is  desired,  the  following  division 
will  be  the  best :  Arteries,  blue ;  vena  portse,  yellow ;  hepatic  vein,  red ; 
hepatic  duct,  white. 

D'*s.  Goddard  and  Neill  have  made  some  successful  injections  of  the  liver, 
by  which  the  four  sets  of  vessels  were  filled ;  using  red  for  the  arteries  and 
blue  for  the  hepatic  vein.  It  will  be  found  more  difficult  to  inject  com- 
pletely the  liver  than  any  other  organ.  After  injection,  sufficient  time  must 
be  allowed  for  drying.  Slices  may  then  be  cut  in  different  directions,  and 
after  these  have  been  moistened  with  turpentine,  may  be  examined  with  a 
low  power.  If  the  vessels  seem  to  be  well  filled  and  distinct,  without 
extravasation,  the  specimens  may  be  permanently  mounted  in  cells  with 
Canada  balsam,  without  heat.] 


-136  THE     SOLIDS. 


PROSTATE    GLAND. 


This  gland  belongs  to  the  compound  follicular  division,  and  not  to 
the  lobular  class  of  glands;  its  structure  consisting  of  clusters  of 
follicles,  united  by  ducts :  these  follicles  are  usually  of  an  oval  form, 
of  large  size,  and  frequently  communicate  with  each  other. 

The  follicles  cannot  be  exhibited  separately  as  such,  being  mere 
excavations  or  cells  which  exist  in  the  substance  of  the  gland,  and 
which  are  lined  by  prolongations  of  the  mucous  membrane  of  the 
urethra. 

That  the  follicles  constituting  the  essential  structure  of  the  prostate 
gland  are  simply  inversions  of  the  genito-urinary  membrane,  is  proved 
by  the  fact  that  the  epithelium  which  lines  them  is  of  the  clavate  form, 
which  has  been  elsewhere  described  as  appertaining  to  the  bladder. 

In  consequence  of  the  large  size  of  the  follicles,  and  of  the  fact  of 
the  epithelium  which  lines  them  forming  on  their  interior  but  a  single 
and  even  layer  of  cells,  a  considerable  space  or  cavity  exists  in  the 
centre  of  each  follicle. 

The  tissue  out  of  which  the  follicles  are  formed,  and  to  the  presence 
of  which  the  prostate  owes  much  of  its  size  and  nearly  all  its  firmness, 
is  a  good  example  of  the  nucleated  variety  of  fibro-elastic  tissue, 
approaching  in  its  characters  very  closely  to  the  muscular  fibre  of 
organic  life. 

The  increase  which  so  generally  takes  place  in  the  size  of  the 
prostate  in  old  age  is  due  to  an  increased  development  of  the  above- 
named  tissue. 

From  the  preceding  description,  it  would  appear  that  the  office  of 
the  prostate  is  simply  to  secrete  mucus,  and  that  it  does  not,  as  has 
been  conjectured,  furnish  any  peculiar  secretion  necessary,  as  some 
even  have  supposed,  to  fecundity. 

The  most  curious  circumstance  about  the  prostate  is  the  almost 
constant  occurrence,  in  considerable  numbers,  of  concretions  or  calculi 
formed  of  concentric  lamellae.  These  calculi  are  situated  in  the  fol- 
licles already  described;  they  differ  from  each  other  very  greatly  in 
size,  form,  and  colour,  and  in  the  number,  arrangement,  and  strength 
of  the  concentric  capsules.  Ordinarily,  the  concentric  lamellae  are 
disposed  around  a  single  nucleus  of  granular  and  amorphous  matter; 
sometimes,  however,  there  are  two  or  even  three  separate  nuclei 
within  each  calculus;  in  these  cases,  each  nucleus  will  be  encircled 
by  its  own  lamellae,  the  entire  of  them  being  also  included  in  a  greater 


GLANDS.  437 

or  less  number  of  larger  lamellae.  The  form  of  the  calculi,  although 
various,  has  a  tendeney  to  the  triangular;  and  the  colour,  although 
differing  in  different  glands,  depends  upon  their  size  and  age,  the 
younger  and  smaller  being  transparent  and  almost  free  from  colour, 
the  older  and  larger  being  of  a  deep  orange  or  ochre  tint.  (Plate 
LYILjfe.  3.) 

The  prostatic  calculi  have  been  noticed  by  several  observers ;  by 
Cruveilhier,  Dr.  Jones,  Mr.  Quekett,  Mr.  Adams,  of  the  London  Hos- 
pital, Dr.  Letheby,  and  myself. 

Dr.  Jones*  describes  them  as  originating  in  oval  or  rounded 
nucleated  and  organic  vesicles,  which  enlarge,  and  then  have  their 
amorphous  contents  arranged  into  concentric  laminae.  Dr.  Letheby 
believes  that  "they  are  concretions  which  arise  exactly  like  those  of 
the  kidney  and  bladder,  viz:  by  a  succession  of  external  deposits;" 
this  view  is  most  probably  the  correct  one. 

Dr.  Letheby  has  favoured  me  with  the  following  observations  on 
the  chemistry  of  these  bodies:  "You  will  find,"  he  says,f  "that  they 
consist  of  phosphate  of  lime,  which  is  mixed  up  with  a  large  quantity 
of  nucleated  fat  cells  and  inspissated  mucus;  the  whole  being  gen- 
erally tinted  with  some  shade  of  yellow  or  red." 

"They  are  slowly  soluble  in  strong  acetic  and  muriatic  acids; 
more  quickly  when  heated,  and  they  then  leave  numerous  fat  globules 
and  remnants  of  cells.  They  are  not  dissolved  by  potash  or  strong 
ammonia.  Heated  before  the  blow-pipe,  they  char,  and  leave  a  small 
residue  of  earthy  matter." 

The  smaller  calculi  resemble  closely  the  concentric  corpuscles  or 
bodies  described  by  Mr.  Gulliver  as  occurring  in.  fibrinous  clots,  and 
many  of  them  do  not  present  concentric  lamellae. 

TUBULAR   GLANDS. 

SUDORIFEROUS    GLANDS. 

The  sudoriferous  are  the  most  numerous  class  of  glands  in  the  body, 
their  apertures  thickly  studding  the  entire  external  surface,  and  far 
outnumbering  the  sebaceous  glands,  which  have  a  somewhat  similar 
distribution. 

They  consist  of  convoluted  tubes  of  nearly  equal  diameter,  which 
unite,  at  irregular  intervals,  with  each  other,  forming  looped  meshes,  all 
of  which  terminate  in  a  single  excretory  duct.  (See  Plate  LVII.j^g-.  4.) 
*  Medical  Gazette,  1847.  f  In  litt. 


438  THE     SOLIDS.' 

The  excretory  duct  is  either  straight  or  coiled  spirally,  and  it 
Always  terminates  in  a  raised  and  rounded  mammillary  process,  evi- 
dent on  the  surface  of  the  epidermis.  (See  Plate  XXIII.  fig.  1.)  It 
is  straight  where  the  epidermis  which  it  has  to  pass  through  is  thin, 
and  where,  in  consequence,  its  course  to  the  surface  is  short;  on  the 
other  hand,  it  is  coiled  in  spires  which  are  remarkable  for  their 
extreme  regularity,  where  this  membrane  is  thick,  as  in  the  palms  of 
the  hands  and  soles  of  the  feet  (see  Plate  XXIV.  fig.  3),  and  where 
as  a  result  its  course  is  prolonged.  The  acting  cause  which  deter- 
mines this  spiral  arrangement  is  probably  the  gradual  flattening  to 
which  the  outer  and  older  layers  of  epidermic  cells  are  continually 
subject  from  pressure. 

The  duct  of  the  sudoriferous  glands  is  formed  by  an  inversion  of 
the  epidermis  itself,  similar  to  that  which  forms  the  lining  of  the  hair 
follicles.  The  sudoriferous  glands  never  open  into  the  hair  follicles, 
but  in  the  intervals  between  them,  and  also  between  the  sensory 
papillae  with  which  the  true  skin  is  covered. 

The  palms  of  the  hands  and  soles  of  the  feet,  being  entirely  free 
from  the  sebaceous  glands,  are  occupied  exclusively  with  the  sudorif- 
erous; they  are  placed  in  lines  or  rows,  which  are  variously  curved, 
and  which  correspond  with  the  arrangement  of  the  sensory  papillae  of 
the  true  skin.  The  apertures  of  the  sudoriferous  glands  on  the  ridges 
of  the  skin  are  just  perceptible  with  the  naked  eye,  but  they  become 
verv  evident  and  conspicuous  with  a  lens  of  moderate  power.  (Plate 
XXIV.  fig.  1.) 

The  secreting  cells  of  the  sudoriferous  glands  are  small. 

The  tubes  are  formed  like  those  of  the  testes  of  a  nucleated  variety 
of  fibro-elastic  tissue,  and  are  surrounded  by  a  similar  plexus  of  capil- 
laries. These  vessels,  as  well  as  the  tubes  themselves,  are  held  in 
position  by  bands  of  fibrous  tissue. 

The  following  calculations  by  Mr.  Wilson  will  serve  to  convey  some 
idea  of  the  extent  and  importance  of  the  sudoriferous  system : 

"  To  arrive  at  something  like  an  estimate  of  the  value  of  the  perspiratory  system  in 
relation  to  the  rest  of  the  organism,  I  counted  the  perspiratory  pores  on  the  palm  of 
the  hand,  and  found  3,528  in  a  square  inch.  Now,  each  of  these  pores  "being  the 
aperture  of  a  little  tube  of  about  a  quarter  of  an  inch  long,  it  follows  that,  in  a  square 
inch  of  skin  on  the  palm  of  the  hand,  there  exists  a  length  of  tube  equal  to  882  inches, 
or  73  5  feet.  On  the  pulps  of  the  fingers,  where  the  ridges  of  the  sensitive  layer  of 
the  true  skin  are  somewhat  finer  than  in  the  palm  of  the  hand,  the  number  of  pores 
on  a  square  inch  a  little  exceed  that  of  the  palm;  and  on  the  heel,  where  the  ridges 
are  coarser,  the  number  of  pores  on  the  square  inch  is  2,268,  and  the  length  of  tube 


GLANDS.  439 

667  inches,  or  47  feet.  To  obtain  an  estimate  of  the  length  of  tube  of  the  perspira- 
tory system  of  the  whole  surface  of  the  body,  I  think  that  2,800  might  be  taken  as  a 
fair  average  of  the  number  of  pores  in  the  square  inch ;  and  700,  consequently,  of  the 
number  of  inches  in  length.  Now,  the  number  of  square  inches  of  surface  in  a  man 
of  ordinary  height  and  bulk  is  2,500 ;  the  number  of  pores,  therefore,  7,000,000 ; 
and  the  number  of  inches  of  perspiratory  tube,  1,750,000;  that  is  146,833  feet,  or 
48,600  yards,  or  nearly  twenty-eight  miles."  * 
See  Appendix,  547  ? 


SUDORIPAROUS   GLANDS. 


[The  paper  by  Mr.  Rainey,  referred  to  in  the  Appendix,  undoubtedly 
gives  the  true  structure  of  the  sudoriparous  glands,  and  their  ducts:  hence 
most  of  the  figures  given  in  the  standard  works  of  Physiology,  of  the  course 
and  structure  of  these  ducts,  will  be  found  incorrect.  The  course  of  these 
ducts  is  perhaps  not  stated  at  sufficient  length  in  the  Appendix.  Mr.  Rainey 
divides  the  duct  into  two  portions,  that  passing  through  the  dermis,  or  dermic 
portion,  and  that  continuous  through  the  epidermis,  or  epidermic  portion. 

"The  membrane  composing  this  duct  is  thin  and  transparent,  and  of  considerable 
strength;  and  becomes  gradually  dilated  at  its  upper  part,  and  terminates  by  becom- 
ing contiguous  with  the  basement  membrane,  covering  the  adjacent  papillae,  and  is 
not  continued  through  the  cuticle  to  the  surface. 

"  The  duct  is  lined  with  epithelium,  which  appears  to  have  no  regular  form  below, 
being  merely  finely  granular,  but  which  becomes  more  distinct  at  its  upper  part, 
where  it  is  continuous  with  the  deep  layer  of  the  epidermis;  namely,  that  lying 
upon  the  basement  membrane. 

"  These  lowest  cells  possess  a  greater  degree  of  coherence  than  those  which  are 
situated  above  them ;  so  that  when  the  epidermis  is  separated  from  the  cutis  after 
maceration,  they  come  away  with  the  cuticle  in  a  tubular  form,  being  in  fact  the 
lining  of  the  duct,  leaving  the  basement  membrane  of  the  papillae  and  the  mem- 
branous part  of  the  duet  in  the  areolar  tissue.  That  part  of  the  duct  which  traverses 
the  epidermis,  and  which  may  be  called,  for  distinction,  the  epidermic  portion,  is 
altogether  of  a  different  structure  to  the  one  just  described,  not  having  like  it  mem- 
branous parietes,  but  merely  being  a  spiral  passage  between  epidermic  cells  and  scales. 

"  In  the  scaly  or  superficial  layer  of  the  cuticle,  the  passage  is  made  up  entirely  of 
epidermic  scales,  placed  with  their  flat  sides  parellel  with  the  axis  of  the  tube  which 
they  compose:  while  in  the  corpuscular  or  deep  layer  of  the  epidermis,  the  passage 
is  situated  between  scales  above  and  cells  below,  which  cells  being  less  and  less 

*  Diseases  of  the  Skin,  p.  18. 


440  THE     SOLIDS. 

perfect,  as  they  are  situated  nearer  the  basement  membrane,  render  the  parietes  of 
the  duct  at  its  origin  between  the  papillse  very  indistinct;  this  part  of  the  duct  being 
merely  a  passage  through  a  confused  stratum  of  cell-nuclei  and  blastema,  and 
gradually  contracting  in  diameter  as  it  approaches  the  dermic  portion,  insensibly 
disappears :  hence  its  inferior  extremity  cannot  be  clearly  defined  by  the  microscope/' 

The  sudoriparous  glands  and  their  ducts  are  best  studied  in  thin  sections 
of  the  skin  from  the  palm  of  the  hand  or  the  sole  of  the  foot.  Fresh 
integument  will  be  found  best  for  making  these  sections,  although  it  will 
require  many  attempts  before  sections  can  be  obtained  which  will  show  the 
gland  and  its  duct  in  its  whole  course  to  its  external  opening. 

Sometimes  thin  sections  can  be  best  obtained  after  the  skin  has  been 
hardened  in  sulphuric  ether,  or  in  a  solution  of  chromic  acid,  or  potash. 

A  good  Valentin's  knife,  or  a  broad  thin  razor,  is  the  best  instrument  for 
making  these  sections.  When  a  satisfactory  specimen  is  obtained,  it  should 
be  mounted  in  a  shallow  cell  with  fluid ;  the  best  for  this  purpose  are 
Goadby's  B-fluid,  naphtha  and  water,  or  a  very  weak  solution  of  chromic  acid. 

Plate  LXXVIL,  fig.  1,  exhibits  the  sudoriparous  glands  and  the  course  of 
their  ducts. 
"  "        fig.  2,  A  more  highly  magnified  view.] 


GLANDS.  441 


AXILLARY    GLANDS. 


These  glands,  first  described  by  Professor  Horner  and  M.  Robin, 
are  probably  but  a  variety  of  the  ordinary  sudoriferous  glands. 

They  are  situated  in  the  axillae,  are  similar  in  organization  to  the 
sudoriferous  glands,  but  are  much  larger  than  these. 

They  doubtless  furnish  the  peculiar  and  odorous  secretion,  which 
characterizes  the  region  of  the  axillae. 

This  odorous  principle,  it  is  said,  exists  in  the  blood  ready  formed, 
and  the  glandulae  merely  separate  it  from  that  fluid.  It  is  also  stated 
that  its  presence  may  be  detected,  in  dried  blood,  on  the  addition  of 
sulphuric  acid,  and  that  its  odour  is  different  in  the  male  and  female; 
also,  that  even  the  blood  of  different  animals  may  be  distinguished  by 
means  of  it;  assertions  which  are  very  doubtful.* 


CERUMINOUS    GLANDS. 


The  ceruminous  glands  are  situated  beneath  the  integument  of  the 
deeper  part  of  the  external  meatus  of  the  ear.  They  occur  mixed  up 
with  numerous  sebaceous  glands,  but  have  no  direct  communication 
with  these,  as  they  open  on  the  surface  by  distinct  apertures. 

They  resemble  very  closely  in  structure  the  sudoriferous  glands 
just  described,  consisting,  like  them,  of  convoluted  and  looped  tubes, 
which  unite  together  and  end  in  a  slender  duct.  They  differ,  how- 
ever, from  the  sudoriferous  glands  in  the  fragile  character  of  the  tubes, 
which  renders  it  somewhat  difficult  to  procure  a  perfect  preparation 
of  one  of  them;  this  difference  seems  to  arise  principally  from  the 
absence,  in  a  great  measure,  of  fibrous  tissue,  whereby,  in  the  sudor- 
iferous glands,  the  tubes  are  bound  together,  as  well  as  of  also 
enveloping  plexuses  of  blood-vessels.     (See  Plate  hVU.Jig.  5.) 

In  the  external  ear  of  the  sheep,  in  which  these  glands  mav  be 
studied  to  great  advantage,  the  tubes  appear  of  a  pale  straw-colour, 
transparent  and  glossy,  with  but  few  apparent  granular  cells,  and 
these  totally  different  from  the  characteristic  cells  of  the  sebaceous 
glands,  filled  with  innumerable  globules  of  oil.  The  granular  cells 
rilling  the  tubes,  and  which  are  usually  concealed  by  a  quantity  of  oily 
fluid,  may  be  made  apparent  by  the  addition  of  acetic  acid.  The  mem- 
brane of  the  tubes  is  composed  of  a  nucleated  form  of  elastic  tissue.f 

*  Annales  d'Hygnne,  vol.  i.  ii.  x.  &c. 

f  It  seems  doubtful,  after  all,  whether  the  ceruminous  are  any  thing  more  than  a 
variety  of  the  sudoriferous  glands. 


442  THE     SOLIDS. 

From  the  fact  of  the  ceruminous  glands  coexisting  with  numerous 
sebaceous  glands,  it  seems  probable  that  the  cerumen  is  the  mixed 
production  of  the  two  descriptions  of  glands. 


The  substance  of  the  kidney,  like  that  of  the  other  large  glands,  may 

be  divided,  for  the  purposes  of  description,  into  two  orders  or  systems 

of  structure  or  apparatus:  the  glandular  or  secretory,  which  is  the 

most  important  and  characteristic;   and  the  vascular,  which  is  but 

subordinate. 

Secreting  Apparatus. 

The  secreting  apparatus  of  the  kidney  consists  of  the  tubes;  their 
enlarged  and  globular  extremities,  which,  in  part,  constitute  those 
peculiar  and  interesting  structures,  the  Malpighian  bodies,  and  their 
contained  granular  cells.  (See  Plate  LVIII.  figs.  1.  6;  Plate  LX. 
figs.  2,  3.) 

Tubes. — The  substance  of  the  kidney  is  divided  into  an  outer 
cortical  and  an  inner  or  medullary  part.  The  former  is  generally 
conceived  to  be  the  secreting  portion  of  the  kidney,  and  the  latter 
merely  the  tubular  or  conducting  portion  through  which  the  urine 
passes  in  its  way  to  the  ureter.  This  notion  of  the  nature  of  the  two 
parts  and  of  their  mutual  relation  is  certainly  erroneous,  as  is  proved 
by  the  facts  that  both  portions  of  the  kidney  are  alike  formed  of  tubes, 
and  that  all  these  tubes  are  abundantly  furnished  with  secreting  cells. 

The  secreting  structure  of  the  cortical  part  of  the  kidney  is  distin- 
guished by  the  large  size  of  its  tubes;  their  tortuous  course;  the  loops 
formed  by  them,  not  merely  on  the  surface  of  the  kidney,  but  also  in 
its  interior;  by  the  globular  enlargements  in  which  they  terminate; 
and  by  the  larger  size,  &c,  of  their  contained  cells. 

The  medullary  part  of  the  kidney  is  characterized  by  the  smaller 
calibre  of  its  tubes,  their  straight  course,  the  absence  of  dilated  extrem- 
ities, and  the  frequency  of  the  union  of  the  tubes  with  each  other. 

The  tubes,  then,  of  the  kidney,  describing  their  course  from  without 
inwards,  commence  in  dilated  extremities  (see  Plate  LX.figs.  2,  3), 
which  form  part  of  the  structure  of  the  Malpighian  bodies;  they  after- 
wards take  a  tortuous  course,  describing  loops  on  the  surface  of  the 
organ,  as  well  as  in  its  interior  (see  Plate  LIX.  fig.  2,  and  Plate 
LVIII.  fig.  1),  until  they  reach  the  medullary  part,  when  their  course 
becomes  straight,  and  where  they  frequently  unite,  especially  near  its 
lower  portion,  in  a  dichotomous  manner,  thus  forming  a  number  of 


GLANDS.  443 

larger  tubes,  which  terminate  in  the  mammillary  processes  which  dip 
into  the  midst  of  the  chambers  called  calices. 

According  to  the  above  description  of  the  course  and  origin  of  the 
tubes  of  the  kidney,  which  is  now  the  generally  received  one,  each 
tube  commences  in  a  single  dilated  extremity;  it  seems  to  me,  how- 
ever, to  be  probable  that  many  of  the  tubes  have  their  origin  in  loops; 
the  fact  of  the  occurrence  of  loops  throughout  both  the  medullary  and 
the  cortical  parts  of  the  kidney,  the  universal  formation  of  loops  on 
the  surface  of  that  organ,  and  the  non-existence  of  dilated  extremities 
of  tubes  on  that  surface,  all  tend  to  prove  the  correctness  of  the  view 
just  mentioned. 

The  tubes  of  the  kidney,  wherever  encountered,  consist  of  a  strong 
and  structureless  basement  membrane  (see  Plate  LVIII.  fig.  1);  it  is 
worthy,  however,  of  especial  notice  that  these  tubes,  as  well  as  their 
globular  terminations,  are  all  enclosed  in  a  frame-work  constituted  of 
a  nucleated  form  of  elastic  tissue.  This  frame- work  is  seen  to  most 
advantage  in  cross-sections;  this  it  is  which  keeps  the  tubes  distinct 
from  each  other,  and  which  explains  the  occurrence  of  intervals 
between  the  tubes,  seen  especially  in  longitudinal  sections.  (See 
Plate  LVIII.  fig.  2.) 

Malpighian  Dilatations. — It  is  certain  that  some,  if  not  all,  of  the 
tubes  terminate  in  enlarged  extremities.  These  dilatations  constitute 
the  Malpighian  bodies  in  part  only;  they  are  of  a  globular  form,  and 
their  diameter  exceeds  five  or  six  times  that  of  the  tube  itself.  (See 
Plate  LX.  Jigs.  2,  3.)  They  vary,  however,  considerably  in  size,  in 
all  parts  of  the  cortical  substance  of  the  kidney;  and  Mr.  Bowman 
states  that  they  are  largest  near  to  the  point  of  junction  between  the 
cortical  and  medullary  portions. 

The  best  way  to  obtain  a  satisfactory  view  of  these  bodies  is  to  tear 
up  with  needles  a  fragment  of  the  cortical  substance  of  the  kidney, 
and  to  search  among  the  divided  shreds  for  the  Malpighian  dilatations, 
which  are  there  met  with  in  all  possible  conditions.  Some  will  be 
seen  entirely  detached,  lying  loose  in  the  water  in  which  the  fragment 
has  been  torn  up,  others  will  be  observed  to  be  attached  to  the  tubes 
which  take  their  origin  from  them.  All  of  these,  however,  whether 
attached  or  loose,  will  occur  in  one  of  two  states;  either  the  surface^ 
of  each  will  be  seen  to  be  constituted  of  convoluted  and  branched  tubes, 
the  vessels  of  the  Malpighian  plexus ;  or  it  will  appear  perfectly  smooth 
and  even.  The  former  condition  is  the  more  frequent;  the  latter  is 
by  far  the  less  common,  and  is  explained  by  the  fact  that  in  this  case 


444  THE     SOLIDS. 

the  Malpighian  dilatation  is  enclosed  in  a  capsule  of  fibro-elastic  tissue 
of  considerable  thickness,  a  continuation  of  that  which  invests  the 
tubes  themselves.     (See  Plate  LX.Jigs.  2,  3,  and  Plate  LVIII.^.  2.) 

The  Malpighian  dilatations  rarely,  if  ever,  extend  to  the  surface  of 
the  kidney;  they  have  been,  in  all  the  instances  in  which  they  have 
been  noticed  by  the  author,  covered  by  convolutions  of  the  tubes. 

Epithelium. — The  epithelium  of  the  kidney  presents  several  well- 
marked  modifications,  in  different  localities  of  that  organ. 

The  epithelium  of  the  tubes  of  the  cortical  part  of  the  kidney,  save 
within  a  short  distance  of  their  junction  with  the  Malpighian  dilata- 
tions, is  composed  of  large  and  angular  scales  or  cells,  which  are 
coarsely  granular,  and  which  form  a  regular  layer  of  pavement  epithe- 
lium lining  the  tubes;  the  centres  of  these  are  unoccupied  with  cells, 
and  are  thus  left  pervious  for  the  passage  of  the  urine.  (See  Plate 
LVIII.  Jig.  6.) 

The  cells  forming  the  epithelium  of  the  tubes  of  the  medullary  part 
of  the  kidney  are  of  much  smaller  size  than  those  contained  in  the 
tubes  of  its  cortical  substance,  consisting  of  nuclei,  surrounded  by  a 
very  narrow  border.     (See  Plate  LVIII.  Jig.  6.) 

The  cells  situated  at  the  neck  of  the  Malpighian  dilatations  are  of 
the  ciliated  kind:  these  were  first  noticed  by  Mr.  Bowman  in  the 
kidney  of  the  frog,  and  that  gentleman  conjectured  their  existence  in 
the  higher  animals;  the  author  has  seen  them  in  action  in  the  sheep, 
rabbit,  and  horse.     (See  Plate  LX.  Jig.  3.) 

Lastly,  the  cells  which  invariably  line  the  Malpighian  dilatations  of 
the  tubes  are  small,  and  furnished  with  oval  nuclei.  (See  Plate  LX. 
Jig.  3.)  Mr.  Bowman  considered  that  epithelium  was  not  constantly 
present  in  these  bodies;  and  that,  when  it  was  so,  it  only  lined  that 
portion  of  them  in  connexion  with  the  tubes.  This  statement  arose 
in  a  misapprehension  of  the  real  structure  of  the  Malpighian  body. 

Vascular  Apparatus. 

The  vessels  of  the  kidney  consist  of  the  renal  artery  and  vein;  also, 
of  a  vein  which  may  be  called  portal :  we  will  first  trace  the  course 
of  the  artery. 

Renal  Artery. — The  renal  artery,  after  its  entrance  into  the  sub- 
stance of  the  kidney,  divides  into  numerous  branches,  some  of  them 
pass  between  the  medullary  cones,  others  traverse  these  in  sets: 
arrived  at  the  cortical  part  of  the  kidney,  many  undergo  a  further 
sub-division,  and  some,  passing  towards  the  Malpighian  dilatations, 


GLANDS.  415 

form  in  part,  upon  its  external  surface,  the  Malpighian  tuft  or  plexus 
of  vessels  (see  Plate  LIX.  Jigs.  1.5);  others  continue  onwards  to  the 
surface  of  the  kidney,  and  there  terminate  in  capillaries.  (See  Plate 
LIX.  _/£§-.  2.)     Such  is  a  brief  sketch  of  the  course  of  the  renal  artery. 

The  branches  of  the  renal  artery  take,  through  the  cortical  part  of 
the  kidney,  a  straight  and  parallel  course;  some  of  these  branches 
give  off  lesser  vessels  on  each  side,  which  pass  towards,  and  are 
expended  upon  the  Malpighian  dilatations,  as  also  are,  ultimately,  the 
terminations  of  the  main  vessels  from  which  the  lesser  ones  proceeded. 
Others,  again,  of  the  larger  and  parallel  branches,  in  like  manner  give 
off  Malpighian  twigs;  but  their  terminations,  in  place  ■  of  being 
exhausted  upon  the  Malpighian  dilatations,  reach  the  surface,  and 
there  form,  with  the  branches  of  the  renal  vein,  an  inter-lobular 
plexus.  It  is  seldom  that  a  branch  of  the  artery  reaches  the  surface 
of  the  kidney,  without  first  communicating  with  the  Malpighian 
dilatations. 

Renal  Vein. — The  renal  vein  has  two  origins :  one  in  the  capilla- 
ries on  the  surface  of  the  kidney ;  these  capillaries,  uniting  with  those 
of  the  renal  artery,  form  the  plexus,  which  ramifies  in  the  interstices 
left  between  the  terminal  loops  of  the  tubes  (see  Plate  LIX.  jig.  2) ; 
the  second  origin  is  in  the  plexus  of  capillaries  surrounding  the  tubes 
formed  by  the  junction  of  the  capillaries  of  both  artery  and  vein; 
from  these  two  origins  and  plexuses  branches  proceed ;  these,  uniting 
with  each  other,  form  larger  vessels,  which  also  pass  through  the 
medullary  part  of  the  kidney  in  sets.     (See  Plate  LVIII.j%s.  4,  5.) 

Portal  Vein. — Each  Malpighian  tuft  or  plexus  of  vessels  is  formed, 
like  other  plexuses,  of  capillaries  derived  in  part  from  an  artery  and 
in  part  from  a  vein.  As  a  single  arterial  twig  proceeds  to  each 
Malpighian  dilatation — the  afferent  vessel,  so  a  single  venous  twig 
departs  from  it — the  efferent  vessel ;  this  vessel  is  usually  of  much 
smaller  size  than  the  artery,  and  terminates  in  the  capillaries  which 
encircle  the  uriniferous  tubes.     (See  Plate  LX.  jig.  2.) 

The  efferent  vessel  of  the  Malpighian  tuft  resembles  in  its  origin 
and  distribution  the  portal  vessel  of  the  liver,  being  in  connexion 
with  capillaries,  at  both  its  origin  and  its  termination:  in  consequence 
of  this  resemblance,  it  has  been  termed  by  Mr.  Bowman  the  portal 
vein  of  the  kidney;  and  as  each  Malpighian  plexus  has  a  separate 
efferent  vessel,  to  the  aggregate  of  these  that  gentleman  applies  the 
term  "portal  system"  of  the  kidney. 

The  above  description  of  the  vascular  distribution  belonging  to  the 


446 


THE     SOLIDS. 


kidney  differs,  in  some  important  respects,  from  that  given  by  Mr. 
Bowman,  as  we  shall  now  proceed  to  make  apparent. 

In  the  first  place,  Mr.  Bowman  describes  the  afferent  vessel  of  the 
Malpighian  tuft  as  piercing  the  membrane  of  the  enlarged  extremity 
of  the  tube,  and  as  forming  within  this,  by  its  numerous  sub-divisions, 
the  Malpighian  plexus :  the  efferent  vessel,  in  like  manner,  perforating 
the  membrane  of  the  dilatation,  or  proper  capsule. 

This  view  of  the  position  of  the  Malpighian  plexus  is  undoubtedly 
incorrect;  this  plexus,  like  every  other  plexus  belonging  to  glands 
formed  on  the  tubular  or  follicular  types,  is  situated  on  the  external 
surface  of  the  basement  membrane,  that  is,  embracing  the  globular 
head  of  the  tubes,  and  lying  between  this  and  the  frame-work  of  elastic 
tissue  already  described.  Analogy,  therefore,  is  entirely  opposed  to 
the  description  of  the  author  of  the  paper  in  the  Philosophical  Trans- 
actions to  which  reference   has  been  made  more  than  once. 

In  the  second  place,  Mr.  Bowman  describes  the  renal  artery  as 
being  spent  upon  the  Malpighian  bodies,  with  the  exception  of  a  few 
branches  given  off  to  the  coats  of  the  excretory  ducts  and  of  the 
larger  vessels ;  while,  according  to  the  author's  observations,  only  a 
proportion  of  the  branches  of  the  renal  artery  are  thus  disposed  of. 

The  accuracy  of  the  foregoing  account  of  the  distribution  of  the 
blood-vessels  of  the  kidney  is  borne  out,  to  a  very  great  extent,  by 
the  results  furnished  by  injection. 

1st,  The  Malpighian  plexus  can  be  injected  with  great  facility  by 
the  artery,  but  not  by  the  vein:  the  reason  of  this  will  be  obvious  on 
a  little  reflection;  the  branches  of  the  renal  artery  pass  directly  to 
the  Malpighian  plexus;  those  of  the  renal  vein,  commencing  from  the 
larger  or  terminal  trunks,  end  either  in  the  plexus  surrounding  the 
tubes  of  the  kidney,  or  in  that  which  lies  on  its  surface  between  the 
convolutions  of  those  tubes;  and  it  is  in  one  or  other  plexus  that  the 
efferent  or  portal  vein  of  the  Malpighian  tuft  terminates;  so  that 
between  the  terminal  branches  of  the  renal  vein  and  the  origin  of 
the  efferent  vessel,  a  complicated  plexus  is  interposed — that  surround- 
ing the  uriniferous  tubes;  the  injection,  therefore,  before  reaching  the 
Malpighian  tuft,  would  have  to  traverse  the  plexus  already  spoken  of; 
and  it  is  this  which  accounts  for  its  being  so  difficult,  if  not  impossible, 
to  inject  the  Malpighian  plexus  from  the  renal  vein. 

2d.  The  plexus  surrounding  the  tubes  may  be  injected  with  care, 
from  both  the  artery  and  vein ;  but  especially  from  the  latter. 

3d.  The  plexus,  ramifying  between  the  loops  of  the  tubes  on  the 


GLANDS.  447 

surface  of  the  kidney,  may  also  be  readily  injected  from  either  artery 
or  vein. 

Occasionally,  the  injection  will  pass  from  the  blood-vessels,  and 
escape  into  the  tubes,  or  their  Malpighian  extremities. 

The  tubes  themselves,  and  very  rarely  their  globular  terminations, 
may  be  injected  from  the  ureter:  this  is  accomplished  more  readily 
in  the  kidneys  of  some  animals,  as  the  horse,  than  in  those  of  man. 

A  complete  Malpighian  body,  then,  consists  of  the  globular  enlarge- 
ment of  the  tube,  over  which  is  spread  the  Malpighian  plexus,  formed 
by  branches  of  the  renal  artery  and  portal  vein;  this  plexus  does  not 
consist  entirely  of  capillary  meshes,  but  of  vessels  of  different  diame- 
ters; the  artery  divides  and  sub-divides:  its  terminal  branches  are, 
however,  capillary  in  size,  but,  in  place  of  forming  distinct  meshes, 
follow  a  serpentine  and  convoluted  course.     (See  Plate  LX.  fig.  2.) 

Mr.  Bowman  conceived,  as  already  noticed,  that  the  Malpighian 
plexus  was  situated  within  the  globular  enlargement  of  the  uriniferous 
tube;  and,  reflecting  on  the  remarkable  structure  of  the  Malpighian 
bodies,  and  on  their  singular  connexion  with  the  tubes,  was  led  to 
consider  that  the  tubes  and  their  plexus  of  capillaries  are  the  parts 
concerned  in  the  secretion  of  that  portion  of  the  urine  to  which  its 
characteristic  properties  are  due  (the  urea,  lithic  acid,  &c),  while 
the  Malpighian  bodies  are  an  apparatus  destined  to  separate  from  the 
blood  the  watery  portion  of  the  urine. 

"It  would  indeed  "be  difficult,"  Mr.  Bowman  writes,  "to  conceive  a  disposition  of 
parts  more  calculated  to  favour  the  escape  of  water  from  the  blood  than  that  of  the 
Malpighian  body.  A  large  artery  breaks  up,  in  a  very  direct  manner,  into  a  number 
of  minute  branches,  each  of  which  suddenly  opens  into  an  assemblage  of  vessels  of 
far  greater  aggregate  capacity  than  itself,  and  from  which  there  is  but  one  narrow 
exit.  Hence  must  arise  a  very  abrupt  retardation  of  the  velocity  of  the  current  of 
blood.  The  vessels  in  which  this  delay  occurs  are  uncovered  by  any  structure. 
They  lie  bare  in  a  eell  from  which  there  is  but  one  outlet,  the  orifice  of  the  tube. 
This  orifice  is  encircled  by  cilia,  in  active  motion,  directing  a  current  towards  the  tube. 
These  exquisite  organs  must  not  only  serve  to  carry  forward  the  fluid  already  in  the 
cell,  and  in  which  the  vascular  tuft  is  bathed,  but  must  tend  to  remove  pressure  from 
the  free  surface  of  the  vessels,  and  so  to  encourage  the  escape  of  their  more  fluid 
contents.  Why  is  so  wonderful  an  apparatus  placed  at  the  extremity  of  each  urin- 
iferous tube,  if  not  to  furnish  water,  to  aid  in  the  separation  and  solution  of  the 
urinous  products  from  the  epithelium  of  the  tube?" — P.  75. 

My  view  of  the  nature  of  the  Malpighian  body  differs,  in  some 
respects,  from  that  entertained  by  Mr.  Bowman.  The  proper  Mal- 
pighian capsule  is  invariably  lined  by  innumerable  granular  cells;  for 


448  THE     SOLIDS. 

this  single  and  simple  reason,  therefore,  I  regard  this  body  as  a  secret- 
ing organ  as  much  as  the  uriniferous  tubes  themselves,  which  present 
an  organization  essentially  the  same.  I  differ,  therefore,  from  Mr. 
Bowman,  who  considers  the  epithelium  of  the  tubes  as  the  sole  true 
secreting  agents  of  the  urine.  I  conceive  that  this  fluid  is  formed  in 
every  part  of  the  tubular  and  Malpighian  surface  of  the  kidney,  and 
I  dissent  from  the  opinion  that  the  Malpighian  body  is  an  apparatus 
destined  for  the  simple  separation  of  the  watery  parts  of  the  urine 
apart  from  any  act  of  secretion. 

Nevertheless,  I  so  far  agree  with  Mr.  Bowman  in  his  theory,  as  to 
consider  that  the  greater  portion  of  the  more  watery  parts  of  the 
urine  proceed  from  the  Malpighian  bodies ;  not,  however,  by  an  act 
of  simple  separation,  but  by  one  of  secretion.  The  peculiar  arrange- 
ment of  the  blood-vessels,  and  the  presence  of  ciliated  epithelium  at 
the  entrance  to  the  tubes,  are  facts  in  themselves  sufficiently  conclu- 
sive of  the  accuracy  of  this  view :  as,  on  the  other  hand,  I  conceive 
the  great  extent  of  secreting  surface  presented  by  the  tubes  to  be  in 
itself  sufficient  to  prove  that  at  least  a  portion  of  the  aqueous  constit- 
uent of  the  urine  emanates  from  this  surface. 

An  accurate  knowledge  of  the  pathology  of  the  kidney  and  urine 
would,  doubtless,  furnish  arguments  conclusive  as  to  the  relative 
functions  and  importance  of  the  tubes,  and  their  enveloping  plexus 
and  the  Malpighian  bodies. 

The  reader  will  at  once  observe  that  one  of  the  arguments  in  favour 
of  Mr.  Bowman's  theory,  urged  in  the  preceding  exposition,  does  not 
hold  good,  in  consequence  of  its  want  of  accordance  with  the  true 
structure.  I  allude  to  the  supposed  entrance  of  the  plexus  into  the 
cavity  of  the  proper  Malpighian  capsule. 

In  birds  and  reptiles,  the  Malpighian  plexus  is  not  formed  of  a 
number  of  convoluted  vessels,  resulting  from  the  repeated  sub-division 
of  the  afferent  artery,  as  is  the  case  in  all  the  Mammalia,  but  simply 
consists  of  a  single  coiled  vessel,  so  that  the  afferent  and  the  efferent 
vessels  of  each  tuft  are  one  and  the  same  by  direct  continuity.  In 
these  classes,  the  efferent  vessel  readily  admits  of  being  injected 
from  the  artery,  and  this  in  consequence  of  the  simplicity  of  the  plexus 
surrounding  the  Malpighian  enlargement. 

The  size  of  the  Malpighian  bodies  varies,  not  merely  in  the  same 
kidney,  but  also  to  a  still  greater  extent  in  the  kidneys  of  different  ani- 
mals :  they  are  largest  in  the  elephant  and  horse,  and  smallest  in  birds. 


GLANDS.  449 


Development  of  the  Kidney. 

According  to  Dr  Carpenter,  "The  first  appearance  of  any  thing  resembling  a 
urinary  apparatus  in  the  chick,  is  seen  in  the  second  half  of  the  third  day.  The 
form  at  the  time  presented  by  it  is  that  of  a  long  canal,  extending  on  each  side  of 
the  spinal  column,  from  the  region  of  the  heart  towards  the  allantois;  and  the  sides 
of  these  present  elevations  and  depressions,  indicative  of  the  commencing  develop- 
ment of  caeca. 

"On  the  fourth  day,  the  Corpora  Wolfflana,  as  they  are  termed,  are  distinctly 
recognised,  as  composed  of  a  series  of  csecal  appendages,  which  are  attached  along 
the  whole  course  of  the  first-mentioned  canal,  opening  into  its  outer  side.  On  the 
fifth  day,  these  appendages  are  convoluted;  and  the  body  which  they  form  acquires 
increased  breadth  and  thickness.  They  evidently  then  possess  a  secreting  function; 
and  the  fluid  which  they  separate  is  poured  by  the  long  straight  canal  into  the  cloaca. 
Between  their  component  shut  sacs  numbers  of  small  points  appear,  which  consist  of 
little  clusters  of  convoluted  vessels  exactly  analogous  to  the  Corpora  Malpighiana 
of  the  kidney.  The  Corpora  Wolfliana,  however,  have  only  a  temporary  existence 
in  the  higher  Vertebrata,  although  it  seems  that  in  fishes  they  constitute  the  perma- 
nent kidney.  The  development  of  the  true  kidneys  commences  in  the  chick  about 
the  fifth  day.  They  are  seen,  on  the  sixth,  as  lobulated  grayish  masses,  which  sprout 
from  the  outer  edges  of  the  Wolffian  bodies ;  and  they  gradually  increase,  the  tem- 
porary organs  diminishing  in  the  same  proportion.  The  sexual  organs,  as  will  be 
hereafter  explained,  also  originate  in  the  Wolffian  bodies;  and  at  the  end  of  foetal 
life,  the  only  vestige  of  the  latter  is  to  be  found  as  a  shrunk  rudiment  situated  near 
the  testes  of  the  male.  The  progress  of  development  in  the  human  embryo  seems 
closely  conformable  to  the  foregoing  account.  The  Wolffian  bodies  begin  to  appear 
towards  the  end  of  the  first  month;  and  it  is  in  the  course  of  the  seventh  week  that 
the  true  kidneys  first  present  themselves.  From  the  beginning  of  the  third  month, 
the  diminution  in  the  size  of  the  Wolffian  bodies  goes  on  pari  passu  with  the  increase 
of  the  kidneys ;  and  at  the  time  of  birth,  scarcely  any  traces  of  them  can  be  found. 
At  the  end  of  the  third  month,  the  kidneys  consist  of  seven  or  eight  lobules,  the 
future  pyramids ;  then-  secreting  ducts  still  terminate  in  the  same  canal,  which  receives 
those  of  the  Wolffian  bodies  and  of  the  sexual  organs.  And  this  opens  with  the 
rectum  into  a  sort  of  cloaca,  or  sinus  urogenitalis,  analogous  to  that  which  is  perma- 
nent in  the  oviparous  Vertebrata.  The  kidneys  are  at  this  time  covered  by  the  supra- 
renal capsules,  which  are  very  large;  about  the  sixth  month,  however,  these  have 
decreased,  while  the  kidneys  have  increased,  so  that  their  proportional  weight  is  as  1 
to  4£.  At  birth,  the  weight  of  the  kidney  is  about  three  times  that  of  the  supra- 
renal capsules,  and  they  bear  to  the  whole  body  the  proportion  of  1  to  80 ;  in  the 
adult,  however,  they  are  no  more  then  1  to  240.  The  Corpora  Wolfliana  are,  when 
at  their  greatest  development,  the  most  vascular  parts  of  the  body  next  to  the  liver; 
four  or  five  branches  from  the  aorta  are  distributed  to  each,  and  two  veins  are  returned 
from  each  to  the  vena  cava.  The  upper  veins  and  their  corresponding  arteries  are 
converted  into  the  renal  and  emulgent  vessels;  and  the  lower,  into  the  spermatic 
vessels.  The  lobulated  appearance  of  the  kidney  gradually  disappears;  partly  in 
consequence  of  the  condensation  of  the  areolar  tissue,  which  connects  the  different 
parts;  and  partly  through  the  development  of  additional  tubuli  in  the  interstices." 

29 


450  THE     SOLIDS. 

It  is  only  necessary  to  observe,  in  addition  to  the  description  of 
Dr.  Carpenter,  that,  although  the  development  of  the  kidney  com- 
mences near  to  the  Wolffian  body,  it  is  yet  not  formed  out  of  it,  but 
has  an  independent  origin  in  its  own  proper  blastema  or  primordial 
matter.  In  its  earliest  condition  in  the  Mammalia,  it  consists  of  tubes 
proceeding  from  the  hilus  outwards  towards  the  circumference  in 
bundles ;  these  tubes  afterwards  separate  and  become  contorted,  yet 
all  terminate  in  enlarged  and  vesicular  extremities — the  Malpighian 
bodies.  In  the  earliest  state  in  which  the  kidney  can  be  examined, 
the  ceeca  alone  exist  in  connexion  with  short  tubes;  the  central  or 
proximal  extremities  are  free,  and  not  yet  united  to  the  ureter.  This 
fact  proves  that  the  kidney  is  not  an  involution  of  the  genito-urinary 
mucous  membrane,  but  an  independent  formation,  as  is,  probably, 
every  other  gland. 

Such  is  a  simple,  concise,  and,  it  is  believed,  in  all  essential  partic- 
ulars, a  correct  account  of  the  normal  anatomy  of  the  kidney. 

Reference  to  the  various  discrepant,  contradictory,  and  often  erro- 
neous statements  of  many  writers  on  this  subject  has  been  hitherto 
purposely  avoided,  lest  such  should  obscure  the  simplicity  of  the 
description  just  given.  A  few  of  the  more  remarkable  statements 
and  opinions  advanced  respecting  the  anatomy  of  the  renal  organs 
may  now,  however,  be  noticed  with  advantage  and  interest. 

Every  statement,  without  exception,  made  by  Mr.  Bowman,  one  of 
the  earliest  and  very  best  writers  on  the  minute  anatomy  of  the  kid- 
ney, has  been  from  time  to  time  contradicted  by  different  observers; 
by  others,  again,  the  descriptions  of  that  gentleman  have  been  con- 
firmed, and  not  denied.  As  might  be  readily  imagined,  the  truth  lies 
not  exclusively  with  either  the  denying  or  the  confirming  observers. 

Thus,  the  reality  of  any  connexion  existing  between  the  tube  and 
the  Malpighian  body  has  been  questioned  and  denied,  and  still  con- 
tinues to  be  so ;  as  also  the  existence  of  a  vibratile  epithelium  in  the 
upper  portion  of  the  uriniferous  tube.  The  first  particular  has  been 
denied  by  Miiller,*  Reichert,"f  Gerlach  and  Bidder;  and  the  second 
has  been  doubted  or  denied  by  Huschke,  Reichert,  and  Bidder.  On 
the  other  hand,  the  observations  of  Schumlansky,J  and  A.  Kolliker 

*  "De  Glandularum  Secernentium  Structura  Peinitiori  Earumque  prima  fonnatione 
in  Homine  atque  Animalibus,  Commentatio  Anatomica." — Cum  Tabulis  sen.  incisis 
xvii.  Leipske,  1830. 

f  Berichl  ilber  die  ForischriUe  der  Mikroscopischen  Anatomie  in  dem  Jahre,  1842; 
von  K.  B.  Reichert,  Prof,  in  Dorpat,  Miiller's  Archiv.  1843. 

\  "De  Structura  Renum,"  8vo.  1788. 


GLANDS.  451 

of  Zurich,  accord  with  those  of  Mr.  Bowman  on  the  first  particular, 
and  those  of  BischofF,  Valentin,  Pappenheim,  Gerlach,  and  Kolliker,* 
on  the  second,  the  latter  observer  describing  the  entire  epithelium  of 
the  tubes  as  ciliated. 

It  is  so  easy,  however,  to  satisfy  ourselves,  in  the  kidney  of  every 
animal,  of  the  reality  of  a  connexion  between  the  tube  and  the  Mal- 
pighian body,  as  well  as  of  the  presence  of  a  ciliated  epithelium,  in 
the  upper  portion  of  the  uriniferous  tubes,  that  it  would  be  perfectly 
unjustifiable  for  observers  again  to  call  these  two  points  in  question. 

The  statement  of  Mr.  Bowman  which  has  met  with  most  opposition, 
is  that  made  as  to  the  entrance  of  the  Malpighian  capillary  plexus  into 
the  cavity  of  the  true  capsule.  Some  observers  have  denied  the  cor- 
rectness of  this  description,  on  the  simple  ground  of  the  anomalous 
position  in  which  the  blood-vessels  would  be  placed,  were  such  an 
arrangement  the  true  one.  This  objection,  however,  is  insufficient  to 
disprove  the  accuracy  of  Mr.  Bowman's  explanation,  since  in  the  liver 
there  is  every  reason  to  believe  that  the  vascular  and  secreting  ele- 
ments of  glands  are  intimately  associated.  Again,  some  observers, 
not  satisfied  with  Mr.  Bowman's  description,  have  given  others. 

Thus,  Gerlachf  says  that  the  Malpighian  capsule  is  not,  as  Mr. 
Bowman  described  it,  a  blind  termination  of  a  uriniferous  duct,  but  a 
retraction  or  introversion,  a  diverticulum  of  the  same  structureless 
membrane  which  forms  the  uriniferous  tubes;  also,  "that  when  the 
Malpighian  capillary  net-work  is  closely  examined,  after  the  capsule 
has  been  entirely  detached  from  it,  we  see  it  in  its  whole  extent 
covered  by  a  thick  layer  of  nucleated  cells,  which  are  continued  from 
the  inner  wall  of  the  capsule  upon  the  Malpighian  vessels;  and  the 
latter  lie  introverted  within  a  layer  of  cells,  like  an  intestine  within 
the  peritoneum.";}; 

Gerlach's  description  is  assuredly  incorrect:  the  views  of  the 
structure  of  the  Malpighian  body,  entertained  by  Bidder, §  although 
they  approach  more  nearly  to  the  truth,  are  also  inaccurate:  he  con- 
siders that  the  glomerulus,  or  vascular  plexus,  is  inserted  or  pushed 

*  Ueber  Flimmerbewig-ungen  in  den  Primordial  Nleren,  Archiv.  fur  Anatomie, 
Physiologie,  und  Wissencliaflliche  Medicin,  Heft  V.  S.  518.   1845. 

f  Beitrdge  zur  Slructurlehre  der  Niere,  von  Dr.  Joseph  Gerlach,  prakt  in  Mainz 
(Mayenee),  Miiller's  Archiv.  1 845. 

I  Edinburgh  Medical  and  Surgical  Journal,  October,  1847. 

§  Ueber  die  Malpighischen  Korper  der  Niere,  von  F.  Bidder  in  Dorpat,  Miiller's 
Archiv.  1845. 


452  THE     SOLIDS. 

into  the  expanded  portion  of  the  uriniferous  canal ;  this  on  its  part 
embracing  and  surrounding  the  glomerulus.  According  to  this  view, 
the  glomerulus  would  still  be  external  to  the  cavity  of  the  dilated 
extremity  of  the  tube,  the  relation  between  the  two  being  comparable 
to  the  head  within  the  double  night-cap. 

The  correct  view  of  the  structure  of  the  Malpighian  body  is,  how- 
ever, much  more  simple  than  either  of  those  just  described.  A 
Malpighian  body,  as  already  stated,  consists  of  the  dilated  extremity 
of  a  uriniferous  tube,  over  which  is  spread  the  Malpighian  plexus: 
these  two  structures  viz:  the  dilatation  of  the  uriniferous  tube,  and 
the  vascular  plexus,  constitute  all  that  is  essential  in  the  anatomy  of 
the  Malpighian  body:  both  are  enclosed  in  a  thick  capsule:  this  is 
not,  however,  a  structure  peculiar  to  the  Malpighian  body,  but  a  mere 
envelope,  similar  to,  as  well  as  a  continuation  of,  that  which  invests 
the  tubes  themselves. 

A  little  reflection  will  show  that  this  view  reconciles  many  of  the 
conflicting  statements  made  in  reference  to  the  anatomy  of  the  Mal- 
pighian body.  The  outer  capsule  referred  to,  which  is  that  spoken  ot 
by  most  other  observers  as  the  true  Malpighian  capsule,  is  evidently 
that  which  Mr.  Bowman  had  in  view  as  the  dilated  extremity  of  the 
uriniferious  tube,  and  it  is  this  which  he  described  as  being  pierced  by 
the  Malpighian  artery — a  description  literally  and  positively  correct. 

The  common  envelope,  which,  however,  as  already  stated,  forms 
no  necessary  part  of  the  Malpighian  body,  is  really  pierced  by  both 
the  afferent  and  efferent  vessels  of  that  body,  as  well  as  by  the  tube. 
(See  Plate  LX.  fig.  3.)  Mr.  Bowman's  error  consists  in  having 
regarded  this  mere  outer  covering  as  the  true  dilated  extremity  of  the 
uriniferous  tube,  which  it  most  certainly  is  not,  and  in  having  neces- 
sarily, as  a  consequence,  overlooked  the  true  extremity  of  the  urin- 
iferous tube  with  its  contained  epithelium. 

Again,  the  confounding  of  this  common  envelope  with  the  true  Mal- 
pighian capsule  accounts  for  the  assertions  of  those  observers  who 
state  that  the  uriniferous  tube  has  no  connexion  with  that  capsule : 
it  has,  indeed,  no  connexion  by  continuity;  it  simply  pierces  it:  of 
the  inner  or  true  capsule,  the  uriniferous  tube  is  absolutely  a 
continuation. 

The  common  envelope  of  the  entire  and  perfect  Malpighian  body 
differs  structurally  from  the  true  capsule :  the  latter  is  thin  and  struct 
ureless ;  the  former,  thick,  and  constituted  of  a  delicately  fibrous  and 
nucleated  form  of  elastic  tissue. 


GLANDS.  453 

Mr.  Toynbee*  is  the  only  writer,  with  whose  observations  I  am 
acquainted,  who  understands  the  true  character  of  what  is  ordinarily 
regarded  as  the  "capsule  of  the  Corpus  Malpighianum:"  this  he  cor- 
rectly describes  as  being  a  distinct  globular  investment,  and  not,  as 
was  supposed,  an  expansion  of  the  tube. 

Notwithstanding,  however,  the  knowledge  of  this  fact,  Mr.  Toyn- 
bee's  views  of  the  structure  of  the  Malpighian  body  appear  to  me  to 
be  far  from  correct. 

Thus,  Mr.  Toynbee  describes  the  Malpighian  body  as  "composed 
of  two  distinct  elements — a  plexus  of  blood-vessels,  and  a  membranous 
capsule,  which  completely  surrounds  and  envelopes  the  plexus." 

Each  Malpighian  body  is  indeed  composed  of  two  distinct  and 
essential  elements,  the  dilated  extremity  of  the  uriniferous  tube 
embraced  and  surrounded  by  the  Malpighian  plexus:  the  outer 
investment,  called  by  Mr.  Toynbee  and  others  "  the  capsule,"  is  not  a 
structure  essential  to  the  Malpighian  body,  since  it  alike  invests  this 
and  the  uriniferous  tubes  for  its  whole  length  attached  to  it. 

Again,  Mr.  Toynbee  describes  the  uriniferous  tube,  after  pene- 
trating the  capsule,  as  twisting  into  a  coil,  and  after  being  in  contact 
with  the  ramifications  of  the  corpus,  as  emerging  from  the  capsule. 

This  last  statement  shows  that  Mr.  Toynbee  was  unacquainted 
with  the  proper  character  of  the  most  important  and  essential  of  the 
two  elements  of  the  Corpus  Malpighianum,  viz :  the  dilated  extremity 
of  the  uriniferous  tube,  filled  with  its  secreting  cells. 

Pathology. 

The  kidney  would  appear  to  be  more  liable  to  morbid  alterations 
than  any  other  organ  in  the  body;  nevertheless,  its  pathology  is  still 
far  from  being  completely  understood,  notwithstanding  that  several 
observers  have  paid  especial  attention  to  the  subject.  Several  of  the 
pathological  conditions  of  this  organ  appear  to  have  been  confounded 
together  under  the  common  term  "Bright's  Disease." 

A  very  frequent  pathological  condition  of  the  secreting  cells  of  the 
kidney  is  that  in  which  they  are  laden  with  globules  of  an  oily  fluid, 
similar  to  those  which  occur  in  the  hepatic  cells  in  the  affection  com- 
monly called  fatty  liver,  or  fatty  degeneration  of  the  liver,  but  which 
would  be  more  correctly  distinguished  by  the  appellation  of  oily  liver; 

*  "  On  the  Intimate  Structure  of  the  Human  Kidney,  and  on  the  changes  which  its 
several  parts  undergo  in  Bright's  Disease."  By  Joseph  Toynbee,  F.  R.  S. — Medico- 
Chirurgical  Transactions,  June  1846. 


454  THE     SOLIDS. 

the    corresponding    affection    in   the    renal   organ   being  known  by 
the  name  of  oily  kidney. 

It  is  this  condition  of  the  renal  cells  which,  in  Dr.  George  John- 
son's* opinion,  constitutes  the  true  Morbus  Brightii. 

The  large,  smooth,  and  mottled  kidneys  are  those  in  which  the  oily 
matter  abounds;  the  smoothness,  according  to  Dr.  Johnson,  depend- 
ing upon  the  uniform  distribution  of  the  tubes  in  the  cortical  portion  of 
the  kidney  with  the  oily  matter. 

The  wasted  and  granular  kidneys,  according  to  the  same  observer, 
are  those  in  which  the  accumulation  of  fat  takes  place  less  rapidly 
and  less  uniformly;  certain  of  the  convoluted  tubes  becoming  dis- 
tended with  fat,  forming  prominent  granulations  ;  and  these,  pressing 
upon  the  surrounding'  tubes  and  vessels,  occasion  their  obliteration 
and  atrophy,  a  wasting  and  contraction  of  the  entire  organ  being  the 
result.  This  condition  attends  the  more  advanced  stages  of  Bright's 
Disease,  and  is  the  sequence  of  the  first-described  form  of  the  affection. 

Dr.  Johnson,  from  numerous  examinations,  has  arrived  at  the  inter- 
esting and  important  conclusion,  that  the  oily  disease  of  the  kidney  is 
generally  coexistent  with  a  similar  affection  of  the  liver,  and  even 
with  steatomatous  deposition  in  the  coats  of  the  arteries,  and  to  a 
less  extent  with  tubercular  deposit  in  the  lungs. 

Dr.  Johnson  also  maintains  the  opinion,  that  the  oily  deposition  is 
not  preceded  by  any  inflammatory  or  congestive  stage :  congestion 
accompanies  the  disease;  but  this  maybe  either  active  or  passive, 
and  when  the  latter,  is  produced  by  the  pressure  to  which  the  vessels 
are  subject  in  consequence  of  the  distention  of  the  epithelial  cells,  and 
which  pressure  gives  rise  to  the  effusion  of  serum  and  blood  within 
the  tubes.  These  results  are,  however,  the  effects,  and  not  the  cause 
of  the  disease. 

The  dropsy  ensuing  on  scarlet  fever,  Dr.  Johnson  considers,  does 
not  depend  upon  the  presence  of  oil  in  the  cells  of  the  kidney;  this 
dropsy  he  regards  as  the  result  partly  of  the  cutaneous  disease,  and 
partly  of  the  effort  made  by  the  kidneys  to  relieve  the  skin,  the  cir- 
culation and  functions  of  which  are  so  much  impaired. 

From  experiments  made  on  cats,  it  appears  that  confinement  in 
dark  chambers  has  the  effect  of  inducing  granular  disease  of  the  kid- 
ney, accompanied  by  deposition  of  oil  in  the  urine. 

*  "On  the  Minute  Anatomy  and  Pathology  of  Bright's  Disease  of  the  Kidney,  and 
on  the  relation  of  the  Renal  Disease,  to  those  Diseases  of  the  Liver,  Heart,  and 
Arteries  with  which  it  is  commonly  associated."  George  Johnson,  M.  D. — Medico- 
Chirurgical  Transactions,  1846. 


GLANDS.  455 

Dr.  Johnson  regards  the  existence  of  albuminous  urine  as  quite  a 
secondary  effect. 

The  results  of  Mr.  Toynbee's  investigation  on  the  pathology  of 
Bright's  Disease  are  very  different,  as  we  shall  presently  perceive, 
from  those  of  Dr.  Johnson:  both  observers,  however,  agree  in  the 
statement  that  there  can  be  no  doubt  that  albuminous  urine  often 
exists,  without  any  deposition  of  fat  in  the  epithelial  cells  of  the  kid- 
ney ;  as  in  dropsy  after  scarlatina. 

The  following  is  Mr.  Toynbee's  own  exposition  of  his  researches 
on  the  pathology  of  Bright's  Disease: 

"  The  First  Stage  of  the  Disease. — In  this  stage  the  kidney  is  enlarged,  and  innu- 
merable black  points  are  visible,  which  are  the  corpora  Malpighiana  dilated,  and  their 
vessels  distended  with  blood,  seen  through  the  capsule.  The  white  spots,  which 
derive  their  appearance  from  the  collection  of  fatty  matter,  begin  to  be  perceptible. 

"  The  peculiar  features  of  this  stage  consist  of  an  enlargement  of  the  arteries  enter- 
ing the  corpora  Malpighiana;  the  dilatation  of  the  vessels  of  the  tuft,  the  capillaries 
and  the  veins ;  an  increase  in  the  size  of  the  capsule  of  the  corpus  and  of  the  tubuli, 
and  a  large  addition  to  the  quantity  of  the  parenchyma  of  the  organ. 

"The  condition  of  the  arteries  is  visibly  changed,  even  at  this  early  period;  the 
artery  entering  the  corpus  being  actually  twice  or  thrice  its  natural  size;  which  is 
the  case  also  with  the  Malpighian  tuft,  and  the  capillary  vessels  which  spring  from 
the  tuft.  An  injection,  in  this  stage,  cannot  very  easily  be  made  to  pass  through  the 
tuft,  and  fill  the  capsule  of  the  corpus — a  circumstance  which  almost  always  attends 
injection  in  the  later  stages  of  the  disease. 

"  The  capillaries  and  veins  are  greatly  enlarged,  giving  to  the  surface  of  the  organ 
the  resemblance  of  net-work.  This  is  the  commencement  of  the  stellated  condition, 
which  is  so  marked  a  characteristic  of  the  next  stage  of  the  complaint. 

"The  tubuli  in  this  stage  are  also  much  increased  in  their  dimensions;  but  the  fat 
which  is  found  in  them  is  soft  and  white. 

"  The  Second  Stage  of  the  Disease. — The  organ  in  this  stage  is  very  greatly 
increased  in  size,  its  surface  is  smooth,  and  presents  numerous  white  spots;  the  cap- 
sule is  but  slightly  adherent  to  the  surface,  and  the  tissue  of  the  organ  is  flabby. 

"The  structural  changes  exhibited  during  this  stage  are  the  following: 

"  1st.  The  artery  of  the  corpus  Malpighianum  becomes  so  greatly  enlarged,  that 
frequently  it  equals  the  dimensions  of  the  tube  itself,  and  is  eight  or  ten  times  its 
natural  size.  -  It  is  tortuous  and  dilated,  and  sometimes,  previously  to  entering  the 
capsule  of  the  corpus,  presents  swellings  analogous  to  those  of  varicose  veins.  The 
primary  branches  of  it,  in  forming  the  tuft,  are  also  distended  to  ten  or  fifteen  times 
their  natural  size,  and  are  not  unfrequently  discovered  external  to  the  capsule sof  the 
corpus,  as  though  thrust  out  by  some  internal  force.  The  vessels  forming  the  tuft 
are  likewise  enormously  enlarged,  and  very  often  the  minutest  branches  are  fully  as 
large  as  the  main  artery  of  the  corpus  in  a  healthy  state. 

"Occasionally  the  tuft  is  broken  up,  and,  instead  of  forming  a  compact  mass,  exhib- 
its its  individual  branches  separated  from  each  other.  At  other  times  the  branches 
of  the  tuft  are  actually  larger  than  the  primitive  artery  of  the  corpus.     Under  these 


456  THE     SOLIDS. 

circumstances  it  is  singular  that  Mr.  Bowman  should  have  made  the  following  remarks 
'  Though  I  have  examined  with  great  care  many  kidneys  at  this  stage  of  the  complaint, 
I  have  never  seen,  in  any  instance,  a  clearly  dilated  condition  of  the  Malpighian  tuft 
of  vessels :'  he  adds, '  on  the  contrary,  my  friend  Mr.  Busk,  an  excellent  observer,  has 
specimens  which  undoubtedly  prove  these  tufts  not  to  be  dilated  in  the  present  stage: 
and  I  possess  injected  specimens  showing  them  in  all  stages,  but  never  above  their 
natural  size.' — It  is  very  possible  that  the  peculiar  injection  used  by  Mr.  Bowman 
may  account  for  the  fact  which  he  mentions ;  and  this  conjecture  is  rendered  ex- 
tremely probable,  as  in  the  later  stages  of  the  disease,  the  Malpighian  tuft  becomes 
pressed  upon  by  the  adipose  accumulation  within,  and,  after  undergoing  compression, 
will  permit  the  fluid  used  in  the  process  of  double  injection  to  pass  through  rather 
than  yield  and  distend.  There  are  instances,  again,  in  which  the  tufts  are  not 
enlarged,  but  appear  healthy,  even  in  organs  otherwise  extensively  diseased :  but  it 
is  important  to  add  that  these  tufts,  both  in  the  second  and  third  stages,  when  but 
slightly  enlarged,  or  even  not  enlarged  at  all,  will  offer  free  passage  to  the  injection, 
on  the  most  gentle  pressure,  without  even  distending  the  whole  of  their  vessels,  and 
thus  indicate  their  diseased  condition. 

"  An  enlargement  of  the  renal  arteries  and  dilatation  of  their  branches,  are  also 
observable  in  this 'stage  of  the  disorder. 

"The  capsule  of  the  corpus,  too,  is  in  this  stage  very  greatly  increased  in  size,  and 
during  the  process  of  injection  becomes  frequently  filled  with  the  injection  thrown 
into  the  arterial  system. 

"  The  tubuli  differ  considerably  from  their  healthy  condition,  being  enlarged  to 
two  or  three  times  their  natural  size,  and  aggregated  together  in  masses,  so  as  to  lie 
in  contact  with  each  other,  and  form  definite,  roundish  bodies:  they  are  also 
extremely  convoluted  with  numerous  dilatations :  frequently  they  are  varicose.  At 
other  times  they  present  distinct  aneurismal  sacs,  which  bulge  out  from  one  part  of 
the  wall  of  the  tube,  to  which  they  are  attached  by  a  small  neck  or  pedicle.  Occa- 
sionally, some  of  the  vessels  of  a  convolution  are  smaller  than  the  others,  and  their 
size  nearly  natural.  The  tubuli  in  the  masses  are  so  closely  packed  that  the  blood- 
vessels are  evidently  compressed,  and  rendered  incapable  of  admitting  an  injection.  At 
times,  a  tube,  even  at  some  distance  from  the  corpus,  becomes  very  convoluted  and 
knotted  into  a  mass. 

"  Parenchyma. — In  cases  where  the  kidney  is  much  enlarged,  the  parenchymatous 
cells  will  be  found  not  merely  increased  in  size,  but  adipose  deposition  will  be  visible 
throughout  them. 

"  The  Third  Stage  of  the  Disease. — The  kidneys  are  smaller  than  their  natural 
size;  hard,  white  granules  are  prominent  on  their  surface,  which  is'  more  or  less 
lobulated;  the  capsule  is  adherent;  vesicles  of  large  size  are  frequently  every  where 
interspersed,  and  numbers  of  smaller  ones  stud  the  whole  surface.  On  making  a 
section,  the  organ  is  found  to  be  deprived  of  blood ;  the  cortical  part  contracted,  the 
blood-vessels  large  and  their  walls  thick. 

"  Arteries. — The  arteries  are  in  a  more  contracted  condition  than  that  described  in 
the  second  stage;  and  the  Malpighian  tuft  is  often  so  changed  from  its  natural  state, 
that  the  greater  part  of  its  vessels  are  not  capable  of  being  injected. 

"  The  capsule  of  the  corpus  has  assumed  a  more  contracted  appearance. 

"The  arteries  in  this  stage  are  so  difficult  to  inject,  that  some  anatomists  have 


GLANDS.  457 

denied  the  possibility  of  the  operation.  The  difficulty  has  its  origin  in  the  great 
pressure,  which  is  exerted  on  the  whole  of  the  arterial  system,  by  the  contraction  and 
hardening  of  the  organ. 

"  Veins. — The  veins  in  this  stage  present,  on  the  surface  of  the  organ,  the  well 
known  stellated  aspect  which  arises  from  the  gradual  pressure  exerted  on  the  trunks 
and  the  contraction  of  the  organ: 

"  Tubuli. — The  tubuli  are  larger  than  in  the  preceding  stage,  and  are  gathered  into 
rounded  masses,  which  form  the  granules  on  the  surface  of  the  organ.  The  latter 
are  of  a  white  hue,  and  are  most  commonly  fully  distended  with  fatty  depositions; 
though  not  unfrequently  they  appear  like  dark  spots ;  the  tubuli,  in  that  case,  being 
full  of  blood.  A  rounded  appearance  is  generally  characteristic  of  the  granules,  in 
each  of  which  the  component  tubule  forms  innumerable  convolutions.  It  is  extremely 
difficult  to  inject  the  tubuli  from  the  ureter;  indeed,  it  is  very  rarely  that  it  is  possible 
to  distend  them  from  this  source ;  nor  is  it  an  easy  matter  to  fill  them  from  the  artery, 
though,  as  will  be  seen  by  the  drawings,  my  efforts  have  not  been  without  success. 

"  The  tubuli  are  filled  with  oily  cells,  granular  matter,  particles  of  various  sizes,  and 
blood  globules. 

"  Parenchyma. — The  parenchyma  is  hard,  and  is  composed  of  elongated  stellated 
cells,  from  the  angles  of  which  fine  threads  proceed,  and  communicate  with  each  other." 

The  researches  of  Mr.  Simon  and  Dr.  Johnson,  which  appeared 
simultaneously  in  the  "  Transactions  of  the  Medico-Chirurgical  Soci- 
ety" for  1847,  have  brought  to  light  other  facts  in  the  pathology  of 
the  kidneys.  It  is  proposed  in  the  next  place  to  give  an  abstract  of 
the  observations  of  each  of  these  observers,  couched,  as  far  as  possi- 
ble, in  the  language  of  the  authors. 

Mr.  Simon's  paper  is  entitled  "On  Sub-acute  Inflammation  of  the 
Kidney." 

"Without  dwelling  on  those  excessively  rare  cases,  where  idiopathic  nephritis 
(independent  of  tubercles  or  of  calculus)  may,  by  its  mere  intensity,  have  ended  in 
large  suppuration  or  (almost  uniquely)  in  gangrene,  I  may  state  that,  in  an  infinite 
majority  of  instances,  inflammation  of  the  kidneys  is  sub-acute.  It  depends  on  some 
humoral  derangement  of  the  entire  system,  and  commences  as  functional  excitement 
manifest  in  an  act  of  over-secretion.  The  morbid  material  which  thus  stimulates  the 
kidney  in  its  struggle  for  elimination  will  sometimes  consist  of  products  of  faulty 
digestion — thelithates  or  the  oxalates;  sometimes  of  matters  cast  upon  the  kidney 
in  consequence  of  suppressed  function  in  other  organs — the  skin,  or  the  liver;  some- 
times will  be  the  mysterious  ferment  of  a  fever  poison — typhus,  or  scarlatina.  In  these 
several  cases,  whatever  variety  may  exist  in  the  detail  of  their  causation,  the  essential 
symptoms  during  life,  and  the  essential  anatomical  changes,  are  strictly  identical  in 
kind.  They  vary  only  in  degree.  The  maleries  morbi  seeks  to  effect  its  discharge  by 
means  of  an  increased  activity  in  the  secreting  functions  of  the  kidney:  it  stimulates 
it;  and  the  result  of  the  stimulation  is  not  so  much  an  increase  of  the  watery  secre- 
tion as  it  is  an  augmented  cell  growth  in  the  tubules  of  the  gland.  This  accel- 
eration of  function   is  incompatible  with  maturity  of  the   secreted  products;  the 


458  THE     SOLIDS. 

epithelial  cells  undergo  various  arrests  or  modifications  of  development,  and  become 
more  or  less  palpably  imbued  with  evidences  of  inflammation. 

.  "If  attention  happen  to  be  directed  to  the  state  of  the  urine,  that  fluid  will  be  found 
to  present  manifest  signs  of  derangement.  Microscopical  examination  will  show  in 
it  numerous  nucleated  cells,  which,  in  the  hurry  of  over-secretion,  have  descended 
from  the  urinary  tubules.  Many  free  cytoblasts  will  likewise  generally  present  them- 
selves, together  with  a  variety  of  those  indefinite  shapes  which  are  known  to  the 
Morphologist  as  abortions  of  cell-growth,  and  which  constitute  a  series  of  connecting 
forms  between  the  pus  globule  and  the  healthy  gland  cell.  Mingled  with  these,  in 
greater  or  less  quantity,  will  be  noticed  also  those  remarkable  fibrinous  threads  first 
described  by  Dr.  Franz  Simon  in  connexion  with  renal  disease.  They  are  seen  as 
exceedingly  delicate,  almost  perfectly  transparent  and  colourless  cylinders,  often  con- 
taining in  their  mass  some  of  the  cell  forms  just  enumerated,  or,  not  unusually,  a  few 
blood  discs,  resulting  from  haemorrhage  into  the  tubules. 

"On  several  occasions,  where  the  renal  irritation  has  been  gouty,  I  have  seen 
crystals  of  lithic  acid  thus  entangled  in  fibrin :  in  other  cases,  though  far  less  fre- 
quently, I  have  distinguished  crystals  of  oxalate  of  lime  similarly  enveloped.  It  is 
well  known  that  these  little  cylinders  are  fibrinous  moulds  of  the  inflamed  urinary 
tubules,  some  of  the  other  contents  of  which  they  bring  with  them  in  their  descent. 
They  are  thus  quite  as  characteristic  of  the  disease  they  attend  as  croupy  expectora- 
tion is  of  tracheitis ;  and  the  cells  or  crystals  included  in  them  often  afford  the  most 
valuable  therapeutical  indications. 

"If  patients  chance  to  die  while  their  urine  is  first  furnishing  the  signs  enumerated, 
it  will  often  happen  that  the  kidneys,  in  their  general  appearance,  present  no  marked 
deviation  from  healthiness.  Their  cortical  substance  may,  indeed,  show  the  minute 
blood  dots  of  intra-tubular  haemorrhage ;  or,  more  rarely,  may  present  here  and  there 
a  pin-head  abscess.  But  often,  perhaps  most  often,  a  superficial  observer  would  pro- 
nounce the  kidneys  healthy;  and,  unless  previous  knowledge  of  the  albuminuria  had 
existed,  they  would  receive  no  farther  attention;  or  the  Case-Book  might  contain  that 
vaguest  of  all  vague  records — '  slight  congestion  of  the  kidney.' 

"On  minuter  analysis,  however,  the  microscope  will  reveal  a  large  amount  of 
disease.  The  ultimate  tubules  are  found,  as  one  might  anticipate,  gorged  with  an 
uneliminable  excess  of  crude  and  vitiated  secretion.  Blood  and  amorphous  matter,  and 
an  infinite  range  of  cell-growth,  from  pus  globules  to  the  healthy  germination  of  the 
gland,  present  themselves  in  various  combinations;  and  among  them  shape  or  colour 
will  sometimes  enable  us  to  discern  the  specific  cause  of  the  derangement — crystals 
of  lithic  acid  or  of  oxalate  of  lime,  or  the  ochreous  tinting  of  bile.  By  products 
such  as  these  the  tubes  are  plugged,  irregularly  distended,  and  not  unfrequently 
burst  and  annihilated.  So  close  is  the  compaction  of  material,  even  in  many  of 
those  tubes  that  have  no  shaped  inflammatory  products  within  them,  that  they  are 
plainly  impervious ;  and  it  is  only  by  artificial  means — by  further  tearing  of  the  frag- 
ment, or  by  use  of  chemical  agents,  that  we  can  satisfy  ourselves  that  the  dense  plug 
in  question  consists  but  of  agglomerated  gland  cells. 

"Now,  in  the  posl  mortem  examination  of  these  chronic  cases,  we  may  or  may  not 
find  the  kidneys  materially  contracted  and  deformed.  It  happens,  to  say  the  least, 
very  frequently  that  the  organ  has  preserved  its  full  size,  and  presents  the  ordinary 
colours.     Perhaps  it  may  have  a  cyst  or  two  on  its  surface.     Between  such  kidneys 


GLANDS.  459 

and  those  which  are  all  knobbed  and  puckered  and  wrinkled,  there  is  not  the  essen- 
tial difference  which  first  sight  would  suggest.  I  shall  first  detail  the  changes  which 
are  latent  in  the  healthier-looking  kidney,  and  subsequently  shall  consider  the 
anatomy  of  the  contracted  specimens,  and  analyze  the  circumstances  which  deter- 
mine that  apparent  atrophy  of  the  gland. 

"In  the  first  instance,  then:  In  commencing  the  microscopical  examination  of  the 
cortical  substance,  we  partially  find  a  similar  state  of  tubes  to  that  described  in  con- 
nexion with  the  sub-acute  attack — a  state,  namely,  of  unequal  distention  and  of 
blocking  up  by  their  own  accumulated  products.  In  the  cases  which  have  lasted 
a  long  time,  these  products  will  often  be  found  to  have  undergone  material  altera- 
tions, from  the  combined  effects  of  pressure  and  absorption.  The  contents  of  the 
epithelial  cells  will  have  lost  much  of  their  natural  fine  granularity;  so  that  the  cells 
will  appear,  even  when  viewed  singly,  to  have  acquired  a  marked  increase  of  solidity 
and  substance.  But,  more  than  this:  in  many  parts  hardly  a  trace  of  tubularity  will 
be  found;  the  tubes  have  been  burst;  their  contents  have  been  interfused  amid  the 
matrix  and  blood-vessels;  and  their  debris  may  be  found  on  opposite  sides  of  a 
preparation — here  black  and  bloated,  there  pale  and  collapsed. 

"  Between  these  trophies  of  disease  there  is  a  new  manifestation.  The  interspace 
is  crowded  with  a  profuse  development  of  cysts,  apparently  foreign  to  the  healthy 
structure  of  the  part.  They  are  of  all  sizes;  some  are  visible  to  the  naked  eye; 
some  are  of  the  magnitude  of  normal  gland  cells,  tW-two  >  but  the  majority  are  of 
an  intermediate  bulk,  ^ 4-Wo-  Even  where  smallest,  they  are  distinguished  by  their 
sharp  outline;  and  the  larger  ones  are  conspicuous  by  their  roundness  and  trans- 
parency, for  all  above  ~±  have  predominantly  fluid  contents. 

"To  explain  this  very  remarkable  phenomenon,  I  take  leave  to  digress  for  a 
moment  from  the  straight-forward  pursuit  of  the  inflammatory  changes.  Any  one  who 
has  made  a  dozen  jiost-mortem  examinations  must  have  observed  cysts  in  the  kidney; 
and  there  can  be  few  pathologists  who  have  not  speculated  on  the  origin  of  these 
growths.  Their  connexion  with  chronic  obstructive  diseases  of  the  kidney  being 
notorious,  some  observers  have  supposed  them  to  originate  in  dilatation  of  the  Mal- 
pighian  capsules;  while  others  have  referred  them  to  distention  of  the  urinary  tubules. 
They  exhibit  great  variety  in  size;  they  are  seen  every  day  as  small  as  mustard-seeds; 
they  have  been  seen  as  large  as  cocoa-nuts.  Thus,  they  obviously  range  from  a  very 
conspicuous  largeness  to  a  size  at  which  the  naked  eye  loses  them.  On  microscopical 
examination  of  cysted  kidneys,  the  same  uninterrupted  gradation  of  size  is  seen  to 
repeat  itself.  The  larger  vesicles  fill  the  field  of  the  microscope;  the  smaller  ones 
diminish  progressively,  so  that  scores  of  them  may  be  in  the  field  at  the  same  time. 

"A  section  of  cysted  kidney,  carefully  examined  with  a  sufficent  magnifying  power, 
may  show  an  astonishing  number  of  these  minute  vesicles;  a  number  quite  dispropor- 
tionate to  that  of  the  larger  cysts  visible  to  the  naked  eye;  so  that,  sometimes,  by  a 
single  one  of  the  latter  class  seen  on  the  surface  of  the  kidney,  I  have  found  myself 
guided  to  a  disease  which  is  substantially  a  vesicular  transformation  of  the  ultimate 
structure  of  the  gland.  The  smallest  cysts  are  simple  nucleated  cells,  of  the  same 
size  (or  rather  within  the  same  limits  of  size)  as  the  common  secretory,  or  epithelial 
cells  of  the  gland.  From  these  cells  they  seem  to  be  distinguished  by  their  very 
definite  outlines,  and  by  their  transparent  fluid  contents :  but  a  step  further  in  micro- 
scopical analysis  shows  that  the  distinction  ceases  at  this  point.     They  show  no  signs 


460  THE     SOLIDS. 

of  a  specific  origin;  no  germs  can  be  found  for  them  other  than  might  equally  belong 
to  epithelial  development;  it  seems  as  though  from  the  same  germs — according,  no 
doubt,  to  varying  influences — healthy  gland  cells  might  grow,  or  these  fluid-hold- 
ing cysts. 

"Fuller  investigation  of  the  specimen  reveals  the  following  very  suggestive  fact: 
the  copious  formation  of  cells  occupies  J,he  place  of  tubes,  holding  their  relation  to 
the  vascular  plexus  of  the  gland;  and,  as  one  gets  to  the  periphery  of  the  portion  of 
gland  thus  transfigured,  one  finds  the  broken  extremities  of  the  original  tubules — 
some  empty  and  collapsed,  others  obstructed  and  often  dilated  with  morbid  accumula- 
tion. In  some  cases,  this  obstructive  material  contains  a  large  proportion  of  fat,  or 
consists  of  it  almost  entirely. 

"  In  short,  in  pursuing  the  minute  anatomy  of  the  cysted  kidney,  we  are  conducted 
back  to  that  same  structural  change  which  we  found  in  connexion  with  sub-acute 
nephritis,  and  demonstrably  dependent  on  inflammatory  processes;  or  sometimes  we 
are  led  to  a  change  in  some  respects  similar  to  this,  associated  with  what  is  known  as 
the  mottled  condition  of  the  kidney. 

"The  pathology  of  cysted  kidney  may  accordingly  be  traced  in  either  of  two  direc- 
tions; from  its  first  causation,  or  from  its  extreme  phenomena.  Following  the  latter 
course,  we  have  ascended  to  a  period  in  the  history  of  cysts,  in  which  they  lie  with 
numberless  gland-germs  amid  the  remnants  of  broken  tubules.  The  unbroken 
tubules  around  show  no  growth  of  such  cysts  in  then-  interior ;  many  are  distended, 
it  is  true,  but  not  with  cysts ;  their  distention  is  of  a  kind  that  we  have  already  inves- 
tigated— inflammatory,  or  perhaps  fatty.  From  the  smallness  attained  by  the  cysts,  it 
seems  quite  obvious  to  me,  that  they  cannot  commence  in  any  transformation  of  the 
tubes  themselves  or  of  the  Malpighian  capsules.  Accordingly,  I  find  the  same 
theory  suggested  by  this  method  of  inquiry,  as  when  the  morbid  change  had  been 
traced  descensiveiy  from  its  causes,  viz :  that  certain  diseases  of  the  kidney  (whereof 
sub-acute  inflammation  is  by  far  the  most  frequent)  tend  to  produce  a  blocking  up  of 
the  tubes:  that  this  obstruction,  directly  or  indirectly,  produces  rupture  of  the  limits 
ary  membrane;  and  that  then,  what  should  have  been  the  intra-tubular  cell-growth 
continues  with  certain  modifications  as  a  parenchytic  development. 

"During  the  growth  of  the  cysts,  they  frequently  exhibit  an  endogenous  formation 
of  cells  which  line  them  as  an  epithelium. 

"If  I  am  right  in  my  statement  of  facts,  and  if  my  theory  of  the  cyst-growth  is 
sound,  then  the  early  stages  of  the  process  are  certainly  points  of  great  interest :  for 
no  one  accustomed  to  the  interpretation  of  nature,  can  doubt  the  reparative  tendency 
of  these  acts.  The  effused  gland-genns  are  the  last  phenomena  of  the  original  dis- 
ease, and  the  first  of  the  attempted  compensation.  The  transparent  nucleated  cysts, 
with  their  clear,  sharp  outlines,  are  not  mere  dropsical  epithelia ;  but  are  organized 
for  secretion  into  their  own  cavities,  so  as  at  least  to  withdraw  from  the  blood,  if  they 
cannot  eliminate  from  the  body,  the  materials  which  fill  them. 

"  Returning  now  to  the  traces  of  inflammation  in  an  uncontracted  kidney,  we  have 
yet  to  ascertain  the  condition  of  its  blood-vessels.  Numbers  of  the  Malpighian 
bodies  are  extinct  for  all  purposes  of  secretion :  their  vessels  obliterated,  their  cap- 
sules wrinkled  round  them;  they  are  dwindled,  opaque  and  bloodless.  Sometimes 
the  contraction  of  the  Malpighian  bodies  is  secondary  on  that  rupture  of  their  capil- 
laries which  Mr.  Bowman  has  indicated  as  the  source  of  intra-tubular  haemorrhage; 


GLANDS.  4G1 

which  rupture,  of  course,  may  have  arisen  either  in  an  augmented  impulse  of  the 
arterial  stream  which  fills  them,  or  in  an  impeded  circulation  through  the  venus  plexus 
into  which  they  discharge  themselves.  But  rupture  of  the  capillaries  is  not  the  only 
cause  of  atrophy,  to  which  these  bodies  are  liable  in  the  disease  under  consideration. 

The  vascular  tufts  may  be  exposed  to  injurious  pressure  from  materials  accumu- 
lated in  their  capsules.  Thus,  I  have  seen  them  flattened  into  a  fourth  of  their 
natural  compass,  while  the  remaining  larger  portion  of  the  capsule  (probably  con- 
tinuous with  an  obstructed  tubule)  has  been  distended  with  a  colourless  and 
transparent  fluid. 

"  Such  is  the  minute  anatomy  of  a  kidney,  which,  having  suffused  from  sub-acute 
inflammation,  has  undergone,  in  consequence,  no  noticeable  alteration  of  volume, 
although  having  in  its  interior  a  very  considerable  new  development. 

"If  the  pathology  of  the  uncontiacted  kidney  be  rightly  understood,  that  of  the 
contracted  specimen  will  follow  it  naturally.  It  seems  to  me  that,  in  the  mere 
destruction  and  absorption  of  tissues,  there  is  abundant  explanation  of  the  shrunken 
dimensions  of  a  kidney  which  has  passed  through  inflammatory  changes.  The  tubes 
have  burst,  and  a  great  portion  of  their  contents  has  been  removed  by  absorption ;  the 
Malpighian  bodies  have  dwindled  to  a  few;  what,  then,  remains  to  make  bulk?  In 
the  uncontracted  specimen  a  false  appearance  of  size  is  maintained  by  the  adventi- 
tious cyst-growth,  which  I  have  described  as  filling  the  interstices  of  the  organ.  But 
the  cysts  are  so  much  over  and  above  the  real  kidney-structure ;  and  if  that  succulent 
surplus  could  be  removed,  the  result,  as  I  have  suggested,  would  be  the  falling 
together  of  wasted  textures  into  a  comparatively  small  compass.  The  cause  of 
shrinking  in  the  gland  is  the  gradual  absorption  of  spoiled  material.  This  cause 
operates  equally  in  all  chronic  cases,  and  its  effects  are  to  be  traced  in  the  uncon- 
tracted, as  in  the  contracted  specimen.  The  main  difference  between  these  two  lies 
in  the  more  or  less  of  interstitial  cyst-development;  the  most  dwindled  are  those  in 
which  least  of  the  newr  growth  has  arisen  or  has  survived. 

"  I  see  no  reason  for  believing  that  the  interstitial  effusion  of  lymph  effects  much 
towards  the  final  contraction  of  the  kidney.  There  are  not  wanting,  I  know,  some 
pathologists  who  will  assert  it  to  be  the  great  agent  in  the  change ;  and  who  conceive 
they  have  seen  the  whole  process  of  fibre-formation,  according  to  the  most  approved 
foreign  cell-theories.  But  I  suspect  that  the  observers  of  new  fibre  will  often  have 
confounded  cause  and  effect.  Coincidently  with  atrophy  of  the  kidney,  there  occurs 
a  contraction  of  the  reticular  matrix;  but  that  contraction  is,  probably,  consequent  on 
a  prior  absorption  of  the  intervening  tissue.  The  meshes  of  the  matrix  come  nearer 
together,  and,  in  a  given  space,  there  is  an  excess  of  fibrous  tissue,  only  because  the 
material  is  withdrawn,  which  originally  expanded  that  matrix  through  three  times  the 
space  it  now7  occupies. 

"  Up  to  the  present  point,  I  have  studiously  avoided  introducing  the  ambiguous  and 
controversial  name  of  'Bright's  Disease.'  And  now  it  will  probably  be  asked,  what 
relation  to  Bright's  Disease  is  borne  by  the  malady  I  have  treated  of?  Is  it  the  same 
thing  under  another  name?  This  question  can  be  answered  in  a  word,  only  when  it 
shall  have  been  settled  what  Bright's  Disease  really  is.  The  history  of  the  complaint 
or  complaints,  included  under  that  title,  was,  perhaps,  originally  systematized  with  too 
much  haste.  Starting  from  dropsy  with  albuminuria,  _and  noticing  that  two  chief 
forms  of  morbid  appearance  corresponded  to  that  symptom  (one,  namely,  where  the 


462  THE     SOLIDS. 

kidney  was  large  and  mottled ;  the  other,  where  it  was  contracted  and  knobbed,  or 
irregularly  granular),  pathologists  have  considered  these  two  forms  as  representing 
the  extreme  stages  of  one  and  the  same  disease. 

"I  must  venture  to  express  a  doubt  as  to  the  justice  of  this  generalization.  After 
investigating  both  classes  extensively,  I  am  convinced  that  the  mottled  and  the  con- 
tracted kidney  do,  in  almost  every  instance,  belong  to  different  morbid  actions ;  not  to 
different  stages  of  the  same. 

"The  mottled  kidneys,  in  an  infinitely  large  proportion  of  cases,  remain  large  and 
mottled  to  the  end. 

"I  have  now  little  further  to  add;  with  respect  to  the  symptoms  of  sub-acute 
inflammation  of  the  kidney,  I  will  make  one  observation  in  addition  to  those  already 
embodied  in  my  paper.  The  descent  of  epithelium  and  its  germs  with  the  urine ; 
the  presence  of  albumen  there,  and  sometimes  of  blood;  the  little  casts  of  the 
tubules — sometimes  wrought  of  fibrin,  sometimes  of  compressed  epithelium; — 
these  signs  belong  equally  to  the  sub-acute  inflammation  and  to  the  scrofulous 
disease.  They  are  signals  simply  of  renal  irritation,  whether  from  one  cause  or  the 
other,  and  I  suspect  they  only  attend  the  scrofulous  disease  at  that  stage  of  its 
progress  in  which  sub-acute  inflammatory  action  is  superadded  to  the  primary  fatty 
degeneration.  Dr.  Johnson's  accurate  observation  has  enabled  us,  under  most  cir- 
cumstances, to  diagnose  the  two  classes  from  each  other;  for,  in  the  scrofulous 
disease  there  will  be  always  seen,  as  he  describes,  more  or  less  oil  entangled  in  the 
fibrinous  casts,  or  gorging  the  cells  which  descend  in  the  urine;  a  phenomenon  which 
does  not  belong  to  the  pure  sub-acute  inflammation." 

The*  following  pages  embrace  the  more  important  portions  of  Dr. 
Johnson's  communication,  which  is  entitled,  "On  the  Inflammatory 
Diseases  of  the  Kidney:" 

"In  a  paper  published  in  the  last  volume  of  the  'Society's  Transactions,'  I  gave 
some  account  of  fatty  degeneration  of  the  kidney,  and  declared  my  intention  to  make 
the  inflammatory  diseases  the  subject  of  a  separate  communication.  On  the  present 
occasion,  I  purpose  to  bring  before  the  Society  the  result  of  some  observations  on 
this  very  interesting  and  important  subject. 

"  In  the  paper  before  alluded  to,  when  referring  to  the  condition  of  the  kidney, 
which  occurs  as  a  consequence  of  scarlatina,  I  stated  that  "  it  is,  in  fact,  an  inflamma- 
tion of  the  kidney,  excited,  like  the  inflammation  of  the  skin  which  constitutes  the 
eruption  of  scarlatina,  by  the  passage  through  the  part  of  the  peculiar  fever-poison; 
and  as  the  inflammation  of  the  skin  terminates  in  an  excessive  development  of 
epidermis,  and  a  desquamation  of  the  surface,  so  the  inflammation  of  the  kidney 
excites  an  increased  development  of  the  epithelium  which  lines  the  urinary  tubules- 
this  material  partly  accumulates  in  and  chokes  up  the  tubes,  while  part  of  it  becomes 
washed  out  with  the  urine,  and  may  be  detected  in  large  quantities  in  that  fluid  by 
the  aid  of  the  microscope. 

"  To  the  account  then  given,  which  I  believe  to  be  essentially  correct,  subsequent 
observations  enable  me  to  make  some  important  additions. 

"On  a  microscopical  examination,  the  convoluted  tubes  are  seen  filled  in  different 
degrees  with  nucleated  cells,  differing  in  no  essential  character  from  those  which  line 


GLANDS.  4G3 

the  tubes  of  the  healthy  gland.  The  chief  difference  between  these  cells,  which  are 
the  product  of  inflammation,  and  those  which  exist  in  health,  consists  in  the  former 
being  generally  of  smaller  size  and  more  opaque  and  dense  in  their  texture.  It  is  very 
interesting  and  important  to  observe  that,  while  the  convoluted  tubes  are  rendered 
opaque  by  this  accumulation  of  cells  in  their  interior,  the  Malpighian  bodies  are  trans- 
parent and  apparently  quite  healthy.  The  straight  tubes  which  form  the  pyramids  also 
contain  an  increased  number  of  cells;  but  there  is  reason  to  believe,  that  these  cells 
are  not  formed  in  these  portions  of  the  tubes,  but  that  they  are  lodged  there  in  their 
passage  from  the  convoluted  through  the  straight  tubes;  the  latter  being  merely 
ducts  leading  into  the  pelvis  of  the  kidney.  Some  of  the  tubes  contain  blood,  which 
has,  doubtless,  escaped  from  the  gorged  Malpighian  vessels  lying  within  the  dilated 
extremities  of  the  tubes.  There  is  no  deposit  outside  the  tubes.  The  essential 
changes  in  the  kidney  are  an  increased  fullness  of  the  blood-vessels,  and  an  abundant 
development  of  epithelial  cells,  differing  slightly  in  general  appearance,  size,  and 
consistence,  from  the  normal  renal  cells;  this  increased  cell-development  occurring 
in  those  portions  of  the  urinary  tubules,  the  office  of  which,  as  Mr.  Bowman  has 
suggested,  is  to  excrete  the  peculiar  saline  constituents  of  the  urine,  while  the  Mal- 
pighian bodies,  whose  office  is  the  separation  of  the  water,  are  unaffected. 

"  The  condition  of  the  urine  in  these  cases,  is  clearly  indicative  of  the  changes 
occurring  in  the  kidney.  After  the  urine  has  been  allowed  to  stand  for  a  short  time, 
a  sediment  forms,  and,  on  placing  a  portion  of  this  under  the  microscope,  there  may 
be  seen  blood  corpuscles,  with  epithelial  cells  in  great  numbers,  partly  free  and  partly 
entangled  in  cylindrical  fibrinous  casts  of  the  urinary  tubes;  and,  very  commonly, 
numerous  crystals  of  lithic  acid  are  present.  As  the  disease  subsides,  which,  under 
proper  treatment,  it  usually  does  in  a  few  days,  the  blood,  fibrinous  casts,  and 
epithelial  cells,  diminish  in  quantity,  and  finally  disappear;  but  traces  of  the  casts 
and  cells  are  still  visible  some  days  after  the  urine  has  ceased  to  coagulate  on  the 
application  of  heat  or  nitric  acid. 

"  The  casts  and  cells  which  appear  in  the  urine,  when  the  disease  is  subsiding,  are 
such  as  have  remained  some  time  in  the  urinary  tubes  before  they  have  become 
washed  out  by  the  current  of  fluid  poured  into  the  tubes  from  the  Malpighian  bodies; 
many  of  the  cells  entangled  in  these  casts  have,  consequently,  become  disintegrated 
and  broken  up  into  amorphous  granular  masses;  thus  presenting  appearances  which  I 
shall  presently  show  are  characteristic  of  the  casts  occurring  in  cases  of  chronic 
nephritis.  Such  is  the  morbid  anatomy  of  the  kidney,  and  such  are  the  characters  of 
the  urine  occurring  as  a  consequence  of  scarlatina. 

"To  the  form  of  renal  disease  here  described  as  occurring  in  connexion  with 
scarlatina,  I  propose  to  give  the  name  of  '  acute  desquamalice  nephritis.'' 

"The  next  form  of  inflammatory  disease,  to  which  I  would  direct  attention,  is  one 
of  great  interest  and  importance.  Two  drawings  by  Mr.  Westmacott  represent  the 
disease  in  two  different  stages ;  one  represents  a  kidney  in  the  earlier  stage ;  the 
other  shows  a  more  advanced  stage  of  the  same  disease.  The  kidney  is  never  much 
enlarged ;  in  the  earlier  stage,  the  size  of  the  organ  is  natural,  and  the  structure  of 
the  cortical  portion  appears  confused,  as  if  from  the  admixture  of  some  abnormal 
product;  there  is  also  some  increase  of  vascularity.  As  the  disease  advances,  the 
cortical  portion  gradually  wastes;  the  entire  organ  becomes  contracted,  firm,  and 
granular;  the  pyramidal  bodies  remaining  comparatively  unaffected  even  in  the  most 


4G4  THE     SOLIDS. 

advanced  stages:  simultaneously  with  the  diminution  in  size  of  the  kidney,  there  is  a 
decrease  of  vascularity.  These  changes  occur  very  gradually ;  the  disease  is  essen- 
tially chronic,  having  a  duration  in  most  cases  of  many  months,  and  in  some  even  of 
several  years.  It  is  almost  confined  to  persons  who  are  in  the  habit  of  partaking 
freely  of  fermented  liquors;  it  is  very  commonly  seen  in  those  who  have  suffered 
from  gout,  and  is  not  uncommon  in  those  who,  having  indulged  freely  in  the  use  of 
fermented  liquors,  have  yet  never  had  an  attack  of  gout.  It  is  sometimes,  but  I 
believe  rarely,  met  with  in  those  whose  mode  of  life  has  been  strictly  temperate  and 
abstemious.  The  symptoms  usually  attending  the  disease,  are  the  following: — 
dropsy,  which  commonly  is  not  excessive,  often  coming  on  only  in  the  most  advanced 
stages,  and  sometimes  being  entirely  absent  throughout  the  entire  progress  of  the 
disease.  The  urine  is  commonly  albuminous:  it  seldom,  however,  contains  a  very 
large  quantity  of  albumen,  and  sometimes  there  is  no  coagulation  on  the  addition  of 
heat  or  nitric  acid.  The  urine  is  sometimes  high-coloured  and  scanty;  but  in  most 
cases,  it  is  rather  abundant,  pale,  and  of  low  specific  gravity — from  1005  to  1010.  In 
some  instances,  the  quantity  of  urine  is  much  greater  than  in  health,  and  this  increased 
quantity  of  urine  is  secreted  by  kidneys  which  are  found  after  death  to  be  contracted 
to  one-third  of  their  original  bulk.  In  urine  of  such  low  specific  gravity,  there  is,  of 
course,  a  deficiency  of  the  solid  constituents,  while  the  blood,  which  is  much  changed 
and  impoverished,  contains  an  excess  of  these  materials. 

"  On  a  microscopical  examination  of  the  kidney,  the  nature  of  the  above-mentioned 
changes  is  very  clearly  revealed,  and  at  the  same  time,  the  attending  symptoms  are 
satisfactorily  explained.  My  account  of  these  phenomena  will  be  rendered  more 
intelligible,  if  I  give  the  facts  and  their  explanation  at  the  same  time. 

"On  placing  thin  sections  of  the  kidney  under  the  microscope,  some  of  the  tubes 
are  seen  to  be  in  precisely  the  same  condition  as  in  a  case  of  acute  desquamative 
nephritis :  they  are  filled  and  rendered  opaque  by  an  accumulation  within  them  of 
nucleated  cells,  differing  in  no  essential  respect  from  the  normal  epithelium  of  the 
kidney :  this  increase  in  the  number,  and  this  slight  alteration  in  the  character,  of  the 
epithelial  cells,  are  the  result  of  the  elimination,  by  the  kidney,  of  mal-assimilated 
products,  which  are  being  continually  developed  in  these  gouty  and  intemperate 
subjects,  and  which  are  not  normal  constituents  of  the  renal  secretion. 

"  There  must  evidently  be  a  certain  limit  to  the  number  of  cells  which  can  be 
formed  in  any  one  of  the  urinary  tubes;  for,  although  some  of  the  cells  escape  with 
the  liquid  part  of  the  secretion,  and  so  may  be  seen  in  the  urine,  as  in  a  case  of  acute 
desquamative  nephritis,  yet,  in  many  of  the  tubes,  the  cells  become  so  closely  packed, 
that  the  further  formation  of  cells  is  impossible,  and  the  process  of  cell-development, 
and,  consequently,  of  secretion  within  that  tube,  are  arrested.  The  cells,  thus  formed 
and  filling  up  the  tube,  gradually  decay,  and  become  more  or  less  disintegrated. 
While  these  changes  are  going  on  in  the  convoluted  portions  of  the  tubes,  the  Mal- 
pighian  bodies  remain  quite  healthy,  the  Malpighian  capsules  for  the  most  part 
transparent,  and  the  vessels  in  their  interior  are  perfect.  From  these  vessels,  water, 
with  some  albumen  and  coagulable  matter,  is  continually  being  poured  into  the  tubes ; 
and,  as  a  consequence  of  this,  the  disintegrated  epithelial  cells  are  washed  out  by  the 
current  of  liquid  flowing  through  the  tubes  so  that,  on  examining  the  sedimentary 
portion  of  the  urine,  we  find  in  it  cylindrical  moulds  of  the  urinary  tubes  composed 
of  epithelium  in  different  degrees  of  disintegration,  and  rendered  coherent  by  the 


GLANDS.  405 

fibrinous  matter  which  coagulates  among  its  particles.  The  appearance  of  these 
casts  are  quite  characteristic  of  this  form  of  'chronic  desquamative  nephritis.' 

"There  is  reason  to  believe,  that  when  the  process  of  cell-development  and  of 
secretion  have  once  been  arrested,  by  the  tube  becoming  filled  with  its  accumulated 
contents,  it  never  recovers  its  lining  of  normal  epithelial  cells;  but,  when  the  disin- 
tegrated epithelium  has  become  washed  away  from  the  interior  of  the  tube,  the 
basement  membrane  may  be  seen,  in  some  cases,  entirely  denuded  of  epithelium;  in 
other  cases,  a  few  granular  particles  of  the  old  decayed  epithelium  remain:  and  again, 
in  other  instances,  the  interior  of  a  tube,  which  has  been  deprived  of  its  proper 
glandular  epithelium,  is  seen  lined  by  small  delicate  transparent  cells,  very  similar  to 
those  which  may  sometimes  be  seen  covering  the  vessels  of  the  Malpighian  tuft. 

"It  now  becomes  interesting  to  ascertain  what  further  change  the  tube  undergoes, 
after  having  lost  its  normal  epithelium.  It  is  quite  certain  that,  as  a  general  rule,  the 
Malpighian  bodies  remain  unaffected,  both  in  structure  and  in  their  office  of  secreting 
the  watery  constituents  of  the  urine,  until  the  whole  of  the  disintegrated  epithelium 
lias  been  washed  out  of  the  tubes.  Of  this  there  are  two  proofs ;  the  first  is  the  fact 
of  a  very  long  convoluted  tube  having  its  contents  completely  washed  out,  and  its 
bnaement  membrane  left  quite  naked:  this  could  happen  only  as  a  consequence  of  a 
current  of  liquid  passing  through  the  tube,  and  there  is  no  known  source  of  such  a 
current  but  the  Malpighian  vessels :  the  second  proof  is  still  more  convincing  and 
satisfactory,  and  it  is  this — that  a  tube  may  often  be  seen  entirely  denuded  of  its 
epithelial  lining,  and  continuous  with  a  Malpighian  body,  in  the  interior  of  which  the 
vessels  are  quite  perfect. 

"  Now,  a  tube  of  this  kind,  deprived  of  its  lining  of  normal  epithelium,  has  manifestly 
lost  its  power  of  separating  from  the  blood  the  solid  constituents  of  the  urine,  while 
the  Malpighian  vessels  remaining  unaffected,  the  power  of  secreting  water  remains. 
Further,  it  appears  probable  not  only  that  the  Malpighian  body  continues  to  secrete 
water,  but  that  the  whole  length  of  a  convoluted  tube  thus  deprived  of  its  proper 
epithelium,  and  either  remaining  naked  or  lined  by  delicate  nucleated  cells,  such  as 
those  which  cover  the  Malpighian  vessels — that  the  entire  length  of  such  a  tube 
becomes  a  secretor  of  water,  which  it  abstracts  from  the  portal  plexus  of  vessels  on 
its  exterior.  This  is  rendered  probable  by  the  appearance  of  the  tube  itself;  and  the 
probability  is  still  further  increased  by  the  fact  of  the  tubes  becoming,  in  some  cases, 
dilated  into  cysts,  which  usually  contain  a  simple  serous  fluid,  without  any  of  the  solid 
constituents  of  the  urine. 

"  It  has  long  been  supposed  that  the  simple  cysts,  which  are  so  commonly  seen  in 
connexion  with  some  forms  of  renal  disease,  are,  in  fact,  dilatations  of  the  urinary 
tubes.  I  am  not  aware  that  any  satisfactory  evidence  has  been  adduced  in  confirma- 
tion of  this  opinion,  but  there  are  some  facts  and  arguments  which  appear  to  me 
abundantly  sufficient  to  prove  the  accuracy  of  the  notion. 

"  1  st.  The  tubes  thus  denuded  of  their  epithelium  are  often  seen  much  dilated.  I 
have  repeatedly  seen  them  three  or  four  times  exceeding  their  normal  diameter.  In 
some  cases  the  dilatation  is  very  sudden,  so  that  the  tube  assumes  a  globular  form, 
and  appears  to  bulge  in  the  intervals  of  the  fibro-cellular  tissue,  in  which  the  tubes 
are  packed:  in  some  cases,  too,  the  basement  membrane  appears  thickened  in  propor- 
tion to  the  dilatation  of  its  cavity.  Now,  this  process  of  dilatation  having  once  com- 
menced, and  the  lower  end  of  the  tube  becoming  closed  by  a  deposit  in  its  interior,  or 

30 


466  THE     SOLIDS. 

by  pressure  from  without,  there  is  no  reason  to  suppose  that  the  process  may  not 
continue  until  a  cyst  as  large  as  a  pea  or  a  walnut  is  formed. 

"2dly.  But  there  are  other  facts  which  afford  a  very  interesting  and  remarkable 
confirmation  of  this  notion.  In  a  case  of  simple  acute  or  chronic  nephritis,  the 
quantity  of  oil  in  the  secreting  cells  of  the  kidney  is  very  small;  sometimes,  indeed, 
none  can  be  detected.  But  it  frequently  happens  that,  after  a  tube  has  been  stripped 
of  its  secreting  cells  in  the  manner  before  mentioned,  an  accumulation  of  fatty  mat- 
ter occurs  in  its  interior,  the  denuded  basement  membrane  becomes  scattered  over 
with  separate  oil  globules,  and  these  increase  in  size  until  they  form  masses  of  fatty 
matter,  having  much  the  appearance  of  adipose  tissue;  and  such  a  mass  is  frequently 
washed  out  from  the  tube,  and  may  be  detected  in  the  urine.  This  occasional  filling 
of  the  tube  with  fatty  matter  is  very  interesting  in  connexion  with  the  fact,  that  in 
some  cases  the  cysts,  which  are  supposed  to  be  dilated  tubes,  are  also  found  filled 
with  the  same  material.  In  two  cases,  I  have  found  a  cyst  as  large  as  a  hazel-nut, 
quite  full  of  oil,  presenting  all  the  characters  of  that  seen  in  the  tubes  which  have 
lost  their  epithelium  in  consequence  of  chronic  inflammation. 

"The  evidence,  then,  of  the  simple  serous  cysts  being  dilated  tubes,  is  the  follow- 
ing:— 1st.  That  tubes  are  often  seen  much  dilated  and  thickened.  2d.  As  the 
inner  surface  of  the  tubes  has  the  appearance  of  being  endowed  with  the  power  of 
secreting  water,  so  the  cysts  usually  contain  a  simple  serous  fluid.  3d.  As  an  accu- 
mulation of  oil  occasionally  occurs  in  the  tubes,  so  the  cysts  are  in  some  instances 
filled  with  the  same  material.  4th.  There  is  no  reason  to  suppose  that  these  cysts 
have  any  other  origin.  It  appears  probable  that  the  Malpighian  bodies  could  not 
become  dilated  into  cysts,  because  an  accumulation  of  liquid  within  the  Malpighian 
capsule  would  necessarily  compress  and  obliterate  the  vessels  of  the  Malpighian  tuft 
and  so  would  cut  off  the  further  supply  of  fluid. 

"  Another  change  consequent  upon  the  destruction  of  the  cells  which  line  the 
urinary  tubes  is,  a  diminished  supply  of  blood,  and  a  gradual  wasting  of  the  tube. 
I  have  already  shown  that  there  must  be  a  close  connexion  between  an  increased 
development  of  epithelial  cells,  and  an  increased  afflux  of  blood  to  the  part.  This  is 
well  seen  in  a  case  of  acute  desquamative  nephritis,  and  vice  versa,  a  more  or  less  com- 
plete destruction  of  the  epithelial  cells  will  be  attended  by  a  corresponding  diminished 
afflux  of  blood,  and  a  consequent  atrophy  of  the  part  affected.  In  every  kidney 
which  has  been  the  subject  of  chronic  inflammation,  there  may  be  seen  tubes  con- 
tracted in  different  degrees,  as  a  consequence  of  the  destruction  of  their  epithelial 
lining;  in  some  instances,  the  basement  membrane  becomes  folded,  and  presents  an 
appearance  not  veiy  unlike  white  fibrous  tissue.  As  a  consequence  of  this  wasting 
of  successive  sets  of  tubes,  there  is  a  gradual  diminution  in  the  bulk  of  the  cortical 
portion  of  kidney,  until,  at  length,  the  entire  organ  becomes  small,  contracted,  and 
granular.  When  a  thin  section  of  a  kidney,  thus  atrophied,  is  placed  under  the 
microscope,  there  may  be  seen  an  abundance  of  fibrous  tissue;  and  this  has  often 
been  described  as  new  fibrous  tissue  developed  during  the  progress  of  the  disease: 
whereas  it  is,  in  reality,  nothing  more  than  the  atrophied  remains  of  the  basement 
membrane  of  the  tubes,  with  the  healthy  fibrous  tissue  arranged  in  the  form  of  a 
net-work  in  which  the  tubes  are  packed,  and  which  now  appears  more  abundant  in 
consequence  of  the  wasting  of  the  tubes. 

"It  has  already  been  stated  that  the  Malpighian  bodies  are  unaffected  in  the 


GLANDS.  467 

progress  of  this  disease;  and  this  is  true,  in  so  far  as  they  remain,  for  the  most  part, 
free  from  any  deposit  or  accumulation  in  their  interior;  but  they  must  necessarily  be 
affected  by  the  changes  occurring  in  other  parts  of  the  organ.  Thus,  the  destruction 
of  many  of  the  Malpighian  bodies  is  a  necessary  consequence  of  the  simultaneous 
wasting  of  the  vessels  and  tubes  which  occurs  in  the  advanced  stages  of  chronic 
nephritis:  and,  during  the  progress  of  the  disease,  the  vessels  of  the  Malpighian  tuft 
will  be  in  a  state  of  more  or  less  active  congestion,  in  proportion  to  the  rapidity  of 
secretion  and  of  cell  development  in  the  tubes  ;  and  one  consequence  of  this  con- 
gestion of  the  Malpighian  bodies  will  be  the  escape  of  serum  into  the  tubes,  and  the 
mixture  of  albuminous  matter  with  the  urine.  The  quantity  of  albumen  in  the  urine 
will  be  great  in  proportion  as  the  disease  approaches  in  activity  to  that  form  which  I 
have  called  'acute  desquamative  nephritis.'  When  the  disease  is  chronic  and  inactive, 
there  may  be  no  albumen  in  the  urine,  or,  it  may  be  present  in  quantities  so  small  as 
not  to  be  detected  by  the  ordinary  chemical  tests;  In  such  cases,  as,  indeed,  for  the 
accurate  discrimination  of  all  forms  of  renal  disease,  the  microscope  will  be  found  an 
invaluable  aid.  It  must  be  remembered  that  the  essential  change  in  this  disease  *s  a 
destruction  of  the  epithelial  cells  in  the  manner  already  described;  the  best  evidence 
of  this  change  being  in  progress  is,  the  presence  in  the  urine  of  moulds  of  the  urinary 
tubes,  composed  of  more  or  less  disintegrated  epithelium ;  and  such  evidence  I  have 
repeatedly  obtained,  when  no  albumen  could  be  detected  by  the  ordinary  heat  and 
nitric  acid  tests. 

"A  sufficient  explanation  has  already  been  given  of  the  small  quantity  of  the  saline 
constituents  excreted  by  the  kidneys  in  cases  of  chronic  nephritis.  It  is  manifest 
that,  if  the  epithelial  cells  are  the  agents  by  which  the  solid  constituents  of  the  urine  are 
separated  from  the  blood,  a  deficient  excretion  of  these  materials  will  be  a  necessary 
consequence  of  the  greater  or  less  destruction  of  the  epithelial  cells. 

"Before  concluding  this  communication  on  the  inflammatory  diseases  of  the  kidney, 
it  appears  desirable  to  allude  very  briefly  to  the  subject  of  my  last  paper,  viz:  'Fatty 
Degeneration  of  the  Kidney;'  my  object  being  to  show  how  essentially  distinct  are 
the  two  forms  of  disease ;  and,  at  the  same  time,  to  explain  the  manner  in  which  they 
are  sometimes  combined. 

"For  some  months  past,  I  have  been  aware  that  fatty  degeneration  of  the  kidney, 
occurs  in  two  distinct  forms. 

"  In  the  simple  fatty  degeneration  of  the  kidney,  all  the  tubes  become  almost 
uniformly  distended  with  oil.  In  a  slight  degree  and  in  the  earlier  stages,  it  is  often 
found,  after  death,  in  cases  where  there  is  no  reason  to  suspect  that  it  has  been  pro- 
ductive of  any  mischief  during  life:  it  is  not  until  the  fatty  accumulation  has  attained 
a  certain  amount,  that  the  functions  of  the  kidney  are  interfered  with.  It  is  this  form 
of  fatty  degeneration  of  the  kidney  which  occurs  in  animals,  as  a  consequence  of 
confinement  in  a  dark  room.  In  the  human  subject,  although  in  the  earlier  stages,  it 
is  a  very  common  occurrence,  yet  in  the  more  advanced  stages  it  occurs  less  fre- 
quently than  the  second  form  of  fatly  degeneration.  This  form  of  the  disease  is 
represented  in  the  5th  figure  of  Dr.  Bright's  3d  plate,  as  well  as  in  the  1st,  2d,  5th, 
and  6th  figures  of  Rayer's  8th  plate.  The  cortical  portion  of  the  kidney,  to  use  the 
words  of  Dr.  Bright,  is  soft  and  pale,  and  interspersed  with  numerous  small  yellow 
opaque  specks.  The  kidney  is  generally  enlarged;  sometimes  it  is  even  double  the 
natural  size.     In  some  cases,  the  cortical  portion  is  somewhat  atrophied  and  granular; 


4b8  THE     SOLIDS. 

but  neither  in  this,  nor  in  the  first  form  of  fatty  degeneration  of  the  kidney,  does  that 
extreme  wasting  with  granulation  occur,  which  is  so  frequent  a  consequence  of 
chronic  nephritis. 

"On  a  microscopical  examination,  the  convoluted  tubes  are  found  filled  in  different 
degrees  with  oil;  some  tubes  being  quite  free,  while  others  are  ruptured  by  the 
great  accumulation  in  their  interior.  The  opaque  yellow  spots  scattered  throughout 
the  kidney,  are  neither  more  nor  less  than  convoluted  tubes  distended,  and  many  of 
them  ruptured  by  their  accumulated  fatty  contents;  just  as  the  red  spots  are  found 
to  be  convoluted  tubes  filled  with  blood.  The  cells  which  contain  the  oil  are  for 
the  most  part  smaller,  more  transparent,  and  less  irregular  in  their  outline  than  the 
ordinary  healthy  epithelium;  they  are  increased  in  number,  and  many  of  them  are  so 
distended  with  oil  as  to  appear  quite  black.  In  parts  of  the  same  kidney,  there 
may  commonly  be  seen  some  of  the  appearances  already  described  as  indicative  of 
desquamative  nephritis.  This  form  of  disease  is  very  commonly  combined  with  fatty 
degeneration  of  the  liver;  but  less  frequently  than  is  the  first  form  of  fatty  degenera- 
tion of  the  kidney. 

"The  peculiarities  of  the  second  form  of  fatty  degeneration  of  the  kidney  result 
from  a  nephritic  condition  of  the  organ,  dependent  on  the  presence  of  some  irritating 
material  in  the  blood  being  associated  with  a  tendency  to  fatty  degeneration;  this 
tendency  resulting  from  the  presence  in  the  blood  of  mal-assimilated  fatty  matter. 
The  nephritic  condition  is  manifest  by  an  increase  in  the  number  of  epithelial  cells; 
the  tendency  to  fatty  degeneration,  by  a  filling  of  many  of  these  with  oil.  Although 
the  two  conditions  are  combined  in  this  and  in  similar  cases,  it  must  be  remembered 
that  they  are  essentially  distinct  in  their  nature  and  origin.  Each  cell  which  escapes 
from  the  kidney  carries  with  it  a  portion  of  the  morbid  material.  The  oil  is  in  the 
form  of  visible  globules ;  while  the  cells  which  contain  no  oil  doubtless  contain  some 
other  material  which  is  invisible,  or  less  readily  seen  than  the  oil  globules. 

"I  have  now  distinguished  and  described  four  conditions  of  the  kidney: 

"1st.     Acute  desquamative  nephritis; 

"  2d.    Chronic  desquamative  nephritis ; 

"  3d.    Simple  fatty  degeneration ;  and 

"  4th.    A  combination  of  fatty  degeneration  with  desquamative  nephritis. 

"  The  diagnosis  of  each  of  these  conditions  of  the  kidney,  during  the  life  of  the 
patient,  is  a  matter  of  the  greatest  importance  with  reference  to  prognosis  and  treat- 
ment; and  the  diagnosis  maybe  made  with  ease  and  certainty  by  a  microscopical 
examination  of  the  nrine. 

The  most  recent  researches  in  this  country  into  the  patnological 
anatomy  of  the  kidneys  are  those  of  Dr  Gairdner,*  who  has  evidently 
devoted  to  the  elucidation  of  this  subject  not  a  little  time  and  atten- 
tion ;  and  the  results  of  these  investigations  will  now  be  given  in  as 
concise  a  form  as  possible. 

Dr.  Gairdner  treats  of  his  subject  under  the  three  following  heads: 
1.  Exudation;  2.  Lesions  affecting  chiefly  the  vascular  system ;  and  3.  Lesions  of 
the  tubes  and  epithelium — an  arrangement  which  will  here  be  followed. 

*  "Contributions  to  the  Pathology  of  the  Kidney,"  by  William  T.  Gairdner, 
M.  D. — Monthly  Journal  of  Medical  Science,  1848. 


GLANDS.  469 


Exudation. 


Exudations  into  the  substance  of  the  kidney  give  rise  to  a  great  variety  of 
external  appearances,  which  have  been  well  figured  and  described  in  the  works  of 
Bright  and  Rayer. 

Exudations  from  the  blood-vessels  may  have  their  seat  in  any,  or  all  the  tissues  of 
the  kidney ;  their  usual  situation,  however,  is  in  the  interior  of  the  tubes,  but  it  also 
occurs  frequently  within  and  around  the  Malpighian  bodies,  and  in  the  inter-tubular 
tissue,  the  tubes  being  quite  clear;  it  is  also  seen  infiltrated  through  all  the  tissues 
in  the  form  of  a  homogeneous  mass,  which  contained  within  it  the  whole  of  the 
anatomical  elements  of  the  kidney. 

The  appearance  of  the  kidney,  as  altered  by  the  presence  of  exudation  in  the  tubes, 
is  subject  to  variations  depending  on  the  amount  of  the  deposition,  and  its  partial  or 
general  character:  one  almost  invariable  effect  of  the  repletion  of  the  tubes,  is  a 
corresponding  diminution  in  the  fullness  of  the  vessels  of  the  cortical  substance, 
particularly  of  the  Malpighian  vessels,  and  the  capillaries  surrounding  the  tubes. 
This  effect  is  evidently  the  result  of  pressure. 

It  is  thus  evident  that  Dr.  Gairdner  does  not  ascribe  the  albuminous  urine  of  Bright's 
Disease  to  secondary  congestion,  or  rupture  of  the  Malpighian  bodies,  caused  by  the 
distension  of  the  tubes  from  accumulated  fat;  and  in  this  particular  his  views  differ 
from  those  already  cited  of  Dr.  George  Johnson. 

The  volume  and  weight  of  kidneys  containing  exudation  in  the  tubes  are  frequently 
much  increased. 

The  exudation  may  be  diffused  throughout  the  organ,  or  it  may  be  confined  to 
certain  portions  of  it.  "  It  then  tends,"  writes  Dr.  Gairdner,  "  to  accumulate  in  cer- 
tain sets  of  the  convolutions  in  which  the  urinary  current  is  least  active.  These 
becoming  partially  blocked  up,  and  ceasing  entirely  to  secrete,  are  thrown  aside  from 
the  outward  current  of  secretion,  and  become  a  centre  of  attraction  for  further 
deposit,  just  as  the  eddies  and  still  waters  at  the  sides  of  a  rapid  stream  receive  from 
it  the  foam  and  floating  bodies  brought  down  from  above.  In  this  way,  more  and 
more  of  the  adjacent  loops  of  tubuli  are  filled  with  the  abnormal  deposit,  and  become 
added  to  the  former  nucleus,  until  the  masses  of  exudation,  thus  imprisoned  within 
tubules  through  which  no  secretion  passes,  form  irregularly  rounded  bodies  in  the 
cortical  substance,  visible  to  the  naked  eye,  more  or  less  prominent  on  the  surface  of 
the  organ,  and  usually  of  an  opaque  yellowish  colour.  These  are  the  granulations 
first  described  by  Dr.  Bright." 

Intra-tubular  exudations,  including  tubercular  and  cancerous  deposits,  may  be  con- 
sidered under  three  heads :  a,  crystalline  or  saline  matters  deposited  from  the  urine ; 
b,  oleo-albuminous,  or  granular'  exudations  from  the  blood  plasma;  c,  exudations 
forming  pus. 

a.  The  most  common  saline  deposit  met  with  in  the  tubes  of  the  kidney  is  the 
amorphous  urata  of  ammonia ;  inasmuch  as  this  salt  is  a  constituent  of  healthy  urine, 
its  presence  in  moderate  quantities  is  merely  a  normal  post-mortem  appearance,  the 
deposition  of  the  salt  resulting  from  the  cooling  of  the  urine  after  death.  In  some 
instances,  however,  it  is  present  in  such  large  quantities,  and  in  these  it  occasions  such 
an  alteration  in  the  appearance  of  the  kidney,  that  it  might,  unless  discriminated  by 
means  of  the  microscope,  be  attributed  to  disease. 


470  THE     SOLIDS. 

Under  the  microscope,  the  urate  of  ammonia  presents  the  appearance,  when  within 
the  tubes,  of  a  fine  molecular  shading  which  entirely  obscures  the  nuclei ;  the  dis- 
tinguishing character  of  this  deposit  is  its  ready  solubility  in  the  dilute  acids,  as  the 
acetic  or  nitric. 

In  one  case  Dr.  Gairdner  detected  the  presence  of  crystals  in  the  tubes,  which,  from 
their  appearance  and  colour,  he  entertained  little  doubt  were  of  uric  acid,  although, 
from  their  minute  quantity,  they  could  not  be  submitted  to  chemical  examination. 

In  this  case  the  urine  was  of  low  specific  gravity,  and  albuminous,  although  there 
was  no  apparent  exudation  within  the  substance  of  the  gland. 

b.  Dr.  Gairdner  includes  under  the  term  "  oleo-albuminous  exudations  from  the 
blood  plasma,"  those  exudations  which  are  fatty  in  their  nature,  as  well  as  the  inflam- 
mation globules,  granular  corpuscles,  or  exudation  granules,  and  corpuscles  of  differ- 
ent writers. 

The  facts  connected  with  the  presence  of  fatty  exudations  in  the  kidney,  have  been 
almost  exhausted  by  the  excellent  reasearches  of  Dr.  Johnson ;  one  additional  fact 
of  interest  has  been  added  by  Dr.  Gairdner.  This  observer  finds  that  the  fatty 
granules  or  globules  are  not  confined  to  the  epithelial  cells,  but  also  that  they  may 
be  freely  disseminated  throughout  the  tubes:  the  tubes  containing  the  fatty  granules 
sometimes  appear  distended,  at  other  tunes  smaller  than  natural,  as  if  they  had  con- 
tracted around  the  fat. 

It  is  probable  that  the  presence  of  the  fatty  globules  in  the  tubes  results  from  the 
rupture  and  disorganization  of  the  cells  which  first  contained  them,  and  that,  there- 
fore, their  location  in  the  tubes  themselves  indicates  a  more  advanced  condition  of 
this  form  of  renal  disorganization. 

c.  The  occurrence  in  the  cortical  substance  of  deposits  of  pus  is  not  very  uncom- 
mon :  their  most  usual  form  is  that  of  small  abscesses,  rarely  exceeding  the  size  of  a 
pea,  and  frequently  much  smaller;  sometimes  confluent,  and  irregularly  disseminated 
throughout  the  cortical  substance. 

The  granular  (oleo-albuminous)  form  of  exudation  is  frequently  found  occupying 
the  tubes  of  the  kidney,  and  occasionally  also  within  the  capsules  of  the  Malpighian 
bodies :  when  in  large  quantity  in  the  latter  situation,  the  tuft  of  vessels  becomes 
compressed,  shrunk,  and,  in  most  cases,  invisible. 

Under  the  heading  "  Partial  distribution  of  the  oleo-albuminous  exudation,"  Dr. 
Gairdner  describes,  in  the  following  terms,  a  peculiar  pathological  condition  of  the 
kidney : — "  I  have  already  described  the  formation  of  granulations  as  dependent  on 
the  accumulation  of  deposit  in  particular  groups  of  tubules  in  the  cortical  substance. 
In  such  cases,  however,  the  affection  is  probably,  at  first,  general;  they  are  very  dif- 
ferent from  the  form  now  to  be  described,  in  which  the  deposit  is  quite  limited  in 
extent,  and  isolated. 

"  There  are  occasionally  met  with,  on  removing  the  capsule  from  the  surface  of  a 
kidney,  irregular  patches,  of  a  paler  colour  than  the  rest  of  the  organ,  sometimes  a 
little  elevated,  sometimes  depressed  below  the  general  surface.  Their  boundary  is 
quite  abrupt,  and  they  are  frequently  surrounded  by  a  well-marked  rose-coloured 
areola,  extending  more  or  less  into  the  surrounding  substance.  On  making  a  section 
of  these  patches,  they  are  found  to  penetrate  into  the  cortical  substance,  and  some- 
times even  a  certain  way  into  the  pyramids.  The  vascular  areola,  when  present, 
extends  round  them  in  every  direction,  and  is  found,  on  examination,  to  consist  of 


GLANDS.  471 

highly-injected  Malpighian  bodies  and  capillaries,  with  or  without  extravasation;  the 
colour  of  the  patches  varies  from  yellowish-gray  to  gamboge-yellow:  their  con- 
sistence is  generally  firm.  On  microscopic  examination,  they  present  a  large  amount 
of  exudation,  varying  from  the  molecular  to  the  large  granular  form.  In  some  cases 
the  tubes  may  be  seen  filled  with  exudation ;  in  others  they  appear  to  be  in  great 
part  obliterated.  In  one  case  I  found  the  Malpighian  bodies  quite  free  of  exudation; 
they  preserved  their  usual  arrangement,  and  were  readily  discoverable  by  a  simple 
lens  on  the  surface  of  the  section.  The  parts  of  the  kidney  not  involved  in  the 
deposit,  generally  present  no  abnormal  appearance." 

Lesions  affecting  cliiejly  the  Vascular  System. 

Variations  in  the  vascular  condition  of  the  kidney  may,  and  frequently  do  exist, 
totally  unconnected  with  organic  change:  thus,  this  organ,  like  all  other  vascular 
structures,  may  be  either  in  a  hyperemic  or  anaemic  state ;  and  these  conditions  may 
affect  either  the  entire  vascular  system,  or  they  may  be  local  only,  or  they  may 
involve  respectively  the  venous  or  arterial  vessels.  The  veins  of  the  kidney  are  dis- 
posed chiefly  in  two  situations,  viz :  on  its  surface,  and  in  the  substance  of  the 
pyramids,  the  cortical  substance  containing  but  few  veins.  On  the  surface  the 
larger  vessels  follow  a  somewhat  stelliform  arrangment,  while  the  capillaries  them- 
selves form  a  mesh-work,  the  meshes  describing  small  pentagonal  or  hexagonal 
spaces,  in  each  of  which  a  single  convolution  of  a  tube  is  situated.  The  state  of 
these  vessels  is  subject  to  much  variation ;  they  may  be  in  an  anaemic  condition,  and 
scarcely  visible,  or  they  may  be  gorged  with  blood ;  in  some  instances  this  engorgement 
is  general,  and  in  others  it  is  confined  to  the  stelliform  vessels  just  referred  to.  These 
conditions,  as  already  observed,  may  be  totally  unconnected  with  disease;  when, 
however,  there  is  great  irregularity  of  injection,  amounting  to  marbling  of  the  sur- 
face, and  great  increase  in  the  size  of  the  stellar  vessels,  these  are  generally 
pathological,  and  result  either  from  partial  obliteration  of  the  venous  net-work,  or  of 
the  extrusion  of  the  blood  from  it,  through  over-distention  of  the  loops  of  tubuli 
which  form  the  intervening  pale  spaces. 

"  The  engorgement  of  the  capillaries  and  Malpighian  tufts  gives  rise  to  two  condi- 
tions: first,  a  generally  diffused  heightened  colour  of  the  cortical  substance;  and 
second,  increase  and  greater  distinctness  of  the  vascular  striae,  running  from  the  base 
of  the  pyramids  to  the  external  surface.  This  latter  species  of  injection  often  exists 
to  a  great  extent,  without  any  corresponding  injection  of  the  rest  of  the  kidney,  and 
in  some  instances  the  red  points  composing  the  striae  are  so  much  increased  in  size 
as  to  form  considerable  petechiae  (one  line  in  diameter,  or  upwards),  in  which  case 
the  petechiae  usually  extend  to  the  surface,  occupying  the  intervening  spaces  of  the 
venous  polygons  above  mentioned.  This  appearance  was  supposed  by  Rayer  to 
occur  from  simple  hypertrophy  and  vascular  injection  of  the  Malpighian  bodies;  but 
Bowman,*  who  has  shown  that  the  Malpighian  bodies  do  not  exist  on  the  surface  of 
the  kidney,  has  also  given  a  better  explanation  of  such  petechia?,  which  he  holds  to 
arise  from  rupture  of  the  Malpighian  tuft,  with  extravasation  of  blood  into  the 
surrounding  tubes.  He  argues  that  the  petechiae  are  of  irregular  form,  and  of  much 
larger  size  than  the  Malpighian  bodies  have  ever  been  observed  to  acquire.    He  gives, 

*  Philosophical  Transactions,  1842. 


472  THE     SOLIDS. 

also,  a  figure  representing  the  occurrence  of  a  similar  appearance,  from  artificial 
injection,  at  the  surface  of  the  kidney.  In  this  figure  the  loops  or  knuckles  of  the 
tubuli  are  seen  filled  with  injection,  presenting  themselves  at  the  surface,  and  sur- 
rounded by  the  venous  net-work." 

The  correctness  of  this  explanation  cannot  he  douhted;  and  it  is  therefore  evident 
that  the  occurrence  of  these  petechiae  must  be  considered  as  invariably  morbid. 

The  anajmic  condition  of  the  kidney,  when  the  result  of  disease,  is  generally 
accompanied  by  increase  in  the  size  of  the  tubes  from  contained  secretion;  and  it  is 
the  pressure  of  these  on  the  surrounding  vessels  that  occasions  their  empty  condi- 
tion, and,  in  some  instances,  even  obliteration.  The  vessels  of  the  Malpighian  tufts 
likewise  become  involved,  and  the  Malpighian  corpuscles  themselves,  thereby  altered 
inform,  from  being  globular  they  become  angular  and  compressed. 

Under  the  heading,  "  Congestion  followed  by  permanent  obliteration  of  the 
Capillaries,"  Dr.  Gairdner  has  described  a  lesion  of  the  kidney,  which  he  has  desig- 
nated by  the  term  "  waxy  degeneration?'  in  contra-distinction  to  the  "fatty  degeneration" 

"  The  appearances  most  characteristic  to  the  naked  eye  of  this  form  of  lesion,  are 
-those  so  admirably  figured  and  described  by  Rayer  as  the  second-  form  of  his 
'  nephrite  albumineuse.'  The  kidneys  are  generally  increased  in  size,  sometimes  very 
remarkably  so.  Their  consistence  varies:  they  are  sometimes  more  flaccid  than  in 
the  natural  condition,  but  always  preserve  considerable  tenacity.  The  surface  is 
either  quite  smooth,  or  more  or  less  depressed  and  furrowed.  The  venous  vascu- 
larity assumes,  to  a  considerable  extent,  the  stellate  form;  the  polygons  are  mostly 
absent;  and  the  extreme  irregularity  and  abruptness  of  distribution  of  the  superficial 
veins  gives  to  the  surface  a  variegated  or  'marbled'  appearance,  which  is  quite 
characteristic  of  this  stage  of  the  affection.  (See  Rayer,  Plate,  VI.  figs.  2,  3.  5 ; 
Bright,  Plate  II.  fig.  1.)  Occasionally,  also,  amid  this  unequal  injection,  there  are  to 
be  found  scattered  petechia?,  indicating  recent  extravasations  of  blood  into  the  tubes. 
On  section,  the  cortical  substance  has  considerable  volume,  and  presents  a  smooth, 
glistening,  almost  semi-transparent  appearance,  which  cannot  be  better  distinguished 
than  by  the  term  waxy.  It  may  partake  in  a  slighter  degree  of  the  variegated 
character  of  the  surface;  more  commonly  it  is  of  uniform  appearance,  and  of  a 
yellowish  or  fawn-colour,  sometimes  verging  into  a  pale  flesh  tint.  The  vascular 
strise  of  the  cortical  substance  are  generally  to  be  traced  by  a  more  or  less  distinct 
injection,  and  a  few  injected  Malpighian  bodies,  or  petechia?  of  extravasation,  are 
sometimes  dispersed  through  the  section.  (See  Rayer,  Plate  X.  fig.  3.)  In  other 
cases,  a  little  further  advanced,  both  the  striae  and  the  Malpighian  bodies  are  nearly 
destitute  of  blood.  (Rayer,  Plate  X.  fig.  1 ;  Bright,  Plate  II.  fig.  1.)  The  pyramids 
frequently  retain  their  normal  vascularity;  sometimes,  however,  they  are  of  a  pale 
colour,  and  their  bases  are  indistinctly  marked — a  condition  which  indicates  the 
progress  towards  a  further  disorganization. 

"  When  a  kidney  in  this  condition  is  carefully  and  minutely  injected,  the  greater 
proportion  of  the  cortical  substance  remains  impervious;  the  injection  however,  can 
frequently  be  made  to  penetrate  as  far  as  the  cortical  stria?,  and  even  to  some  of  the 
Malpighian  bodies.    (See  Rayer,  Plate  X.  fig.  2;  Bright,  Plate  II.  fig.  3.) 


GLANDS.  473 

"  From  these  circumstances  it  is  obvious,  that  the  lesion  above  described  consists 
in  an  obliteration  or  obstruction  of  the  capillary  system  of  vessels  throughout  the 
organ,  and  a  partial  obliteration  of  the  veins  on  its  surface.  There  is  also  every 
probability  that  this  condition  is  secondary  to  one  in  which  there  is  a  high  degree  of 
congestion  of  the  organ.  The  extravasations,  the  occasionally  injected  Malpighian 
bodies,  and  the  highly  injected  though  partially  distributed  stellar  veins,  leave  no 
doubt  that  the  state  of  congestion  described  as  the  first  form  of  albuminous 
nephritis  by  Raver,  is  really  the  antecedent  of  the  present  or  second  form. 

"  To  any  one  who  is  familiar  with  the  marbled  and  waxy  kidney  here  described, 
there  can  be  no  difficulty  in  recognising  a  further  stage  of  the  same  lesion,  in  which 
the  organ  is  perfectly  pale,  both  on  the  surface  and  on  section,  with  the  exception, 
perhaps,  of  a  very  few  stellated  superficial  veins.  The  kidney  in  this  stage  (the 
transition  to  which  seems  to  be  represented  in  Rayer,  Plate  VI.  fig.  4)  is  still  heavy 
and  voluminous;  it  acquires  additional  firmness  and  elasticity,  and  assumes  much  of 
the  general  appearance  of  a  true  non-vascular  texture.  It  varies  from  a  light  yellow 
to  a  fawn-colour,  which  extends  to  the  pyramids,  the  bases  of  which  become  still 
more  confused  and  intermingled  with  the  cortical  substance  than  in  the  marbled 
kidney.  The  capsule  is  frequently  more  firmly  adherent  to  the  external  surface 
than  in  health. 

"From  the  pale  and  yellow  appearance  of  the  kidney  in  this  stage,  it  is  very  apt  to 
be  mistaken,  even  by  a  practised  eye,  for  an  extreme  degree  of  the  fatty  degenera- 
tion. A  well-marked  example,  indeed,  will  hardly  give  rise  to  this  error,  if  attention 
be  directed  to  the  degree  of  firmness  of  the  organ,  the  peculiar  lustrous  character  of 
the  cut  surface,  and  the  entire  absence  of  the  opaque  granulations  of  Bright,  or  of 
that  dull  tint  which  distinguishes  the  excessive  degrees  of  the  fatty  disease.  The 
appreciation  of  these  characters  is,  however,  more  difficult  where,  as  sometimes 
happens,  exudation  is  also  present;  and  the  distinction  which  has  escaped  the  acute 
observation  of  M.  Rayer,  has  undoubtedly  been  overlooked  by  many  other  observers. 

"The  microscopic  characters  of  this  lesion  are  chiefly  negative.  There  is  not 
unfrequently  an  entire  absence  of  exudation ;  indeed,  in  the  most  marked  cases  of 
the  lesion,  I  have  seldom  found  even  the  slightest  trace  of  any  abnormal  deposit. 
Occasionally,  however,  there  is  a  very  minute  quantity  of  fatty  exudation  In  the  tubes, 
generally  in  very  small  granules,  and  scattered  throughout  the  organ.  The  tubes 
are  either  natural,  or  in  the  advanced  stages  pass  into  some  of  the  states  hereafter  to 
be  described.  The  capillary  vessels  surrounding  the  tubes  are  not  visible,  and  in 
their  place  there  is  fibrous  tissue,  which  in  this  form  of  lesion  always  appears  some- 
what exaggerated.  The  Malpighian  bodies  are  also  frequently  seen  in  process  of 
obliteration,  and  surrounded  by  dense  capsules  of  fibrous  tissue.  The  epithelium  is 
frequently  altered  in  character,  but  its  changes  follow  no  fixed  rule. 

"The  absence  or  scantiness  of  exudation,  taken  in  connexion  with  the  extent  of 
degeneration  appreciable  by  the  naked  eye,  are  amply  sufficient  characters  to 
distinguish  this  lesion  from  the  extreme  stages  of  the  fatty  disease." 


474  THE     SOLIDS 


Lesions  of  the  Tubes  and  Epithelium. 

Some  of  these  lesions  have  been  already  described  under  the  head  of  exudation; 
but  there  are  others  which  are  not  less  important  than  those  formerly  alluded  to, 
and  which  are  very  frequently  found  in  connexion  with  them. 

Imperfect  Development  of  the  Epithelium  Cells  and  Nuclei- — The  epithelium  cells 
and  nuclei  vary  in  size  and  characters  within  certain  limits  even  in  healthy  kidneys; 
the  nuclei  less  so  than  the  cells  themselves;  but  in  all  kidneys,  whether  healthy  or 
diseased,  the  nuclei  which  are  most  closely  adherent  to  the  basement  membrane  are 
less  perfectly  circular,  and  of  considerably  smaller  size,  than  those  lining  the  tubes 
and  surrounded  by  complete  cell-walls. 

Those  acquainted  with  the  normal  anatomy  of  the  kidney  will  be  able  to  determine 
the  limits  of  variations  in  the  epithelium  and  nuclei  compatible  with  a  state  of  health. 

In  very  many  pathological  conditions  of  the  organ,  the  nuclei  occur  in  various 
places  almost  wholly  devoid  of  cell-walls.  They  may  be  more  abundant  or  more 
scanty  than  usual;  and  often  appear  in  great  profusion,  huddled  together  in  con- 
fused masses,  and  mixed  with  shreds  of  membrane  and  amorphous  molecular  matter, 
not  soluble  in  acetic  acid.  This  appearance  of  dtbris,  which  no  doubt  results  from 
disintegration  of  the  cell-walls,  most  frequently  occurs  in  kidneys  which  are  abnor- 
mally soft  and  large,  and  from  the  cut  surface  of  which  an  unusually  large  quantity 
of  turbid  whitish  juice  may  be  scraped.  Such  softened  and  altered  kidneys  occur 
frequently  in  fever  and  other  diseases. 

A  more  unequivocal  pathological  change  (often  occurring  along  with  the  above)  is 
the  small  size  and  altered  form  of  the  nuclei  throughout  the  organs,  these  not  being 
more  than  half  the  usual  size,  and  always  destitute  of  cell-walls.  Sometimes  they 
float  scattered  and  solitary  in  the  field  of  the  microscope;  at  other  times,  they 
appear  aggregated  together  either  by  two's  or  three's,  or  in  much  greater  numbers, 
the  connecting  medium  being  a  transparent  and'filmy  substance,  the  nascent  or 
undeveloped  cell-membrane  which  has  separated  from  the  basement  membrane,  along 
with  the  half-developed  or  young  nuclei  above  described.  These  aggregations  of 
young  nuclei  are  sometimes  mingled  with  the  amorphous  dtbris  of  effete  epithelium,  or 
with  granules  and  molecules  of  oleo-albuminous  exudation,  or  of  lithate  of  ammonia, 
which  communicate  to  them  a  dark  and  confused  appearance:  not  unfrequently,  also, 
these  masses,  when  freed  from  the  tubes,  retain  more  or  less  of  their  form,  and 
present  so  exactly  the  appearance  of  the  casts  of  the  tubuli  seen  by  Franz  Simon, 
and  many  other  observers,  in  the  urine,  as  to  leave  no  doubt  of  their  identity  with 
these  bodies. 

Desquamation  of  the  Epithelium. — The  changes  above  described  are  generally 
accompanied  by  an  extremely  rapid  generation  of  nuclei,  which  are  separated  from 
the  basement  membrane  in  an  imperfect  state,  and  earned  away  along  with  the  urine, 
in  which  they  may  be  readily  detected. 

In  some  cases  of  desquamation  of  the  epithelium,  it  is  scarcely  possible  to  recog- 
nise any  departure  from  the  usual  condition  of  the  kidney,  either  with  or  without  the 


GLANDS.  475 

assistance  of  the  microscope.  The  degree  of  vascularity  is  very  various  in  different 
specimens,  and  the  epithelium  thrown  off  is  so  quickly  resupplied,  that  there  is  no 
very  observable  change  in  the  microscopic  condition  of  the  tubules.  In  one  very 
intense  case,  in  which  ten  pounds  of  very  watery  urine,  loaded  with  an  epithelial 
sediment,  were  passed  daily  for  some  weeks  before  death,  the  kidneys  were  small, 
flaccid,  and  bloodless ;  many  of  the  tubes  were  quite  full  of  nuclei  closely  heaped 
together;  some  of  the  nuclei  were  under-sized;  the  cells,  when  entire,  were  much 
compressed  and  angular.  In  an  another  instance,  where  urine  was  passed  in  large 
quantity  and  full  of  epithelial  debris,  during  the  last  two  months  of  life,  the  kidneys 
were  found  in  an  opposite  condition,  viz :  large  and  congested,  and  with  a  firmness 
and  smoothness  of  section  like  the  first  stage  of  the  waxy  degeneration  formerly 
described.  In  this  case,  the  condition  of  the  tubuli  was  in  most  parts  quite  natural ; 
in  some,  however,  there  was  extravasated  blood,  and  in  others  the  epithelium  had 
accumulated  in  abnormal  quantity.  In  both  these  cases  there  was  imperfect  develop- 
ment of  the  epithelium,  but  cases  have  occurred  to  me  in  which  this  character  was 
by  no  means  wTell  marked :  the  crowding  of  the  tubes  with  nuclei,  although  frequently 
found  in  the  earlier  stages  of  desquamation,  is  not  invariably  present;  and  the 
tubes  were  even  seen  to  be  gorged  with  epithelium  in  a  case  where  none  had  been 
separated  from  the  urine  for  weeks  before  death. 

So  long,  therefore,  as  the  epithelium  is  freely  regenerated,  the  kidneys  may  present 
a  tolerably  healthy  appearance,  even  on  minute  examination :  after  prolonged  disease, 
however,  further  changes  take  place ;  the  epithelium  becomes  more  sparingly  gener- 
ated, and  is  thrown  off  in  the  coherent  masses  above  described,  leaving  the  basement 
membrane  in  portions  bare,  or  with  a  few  scattered  oval  nuclei,  much  smaller  than 
those  cast  off,  adhering  to  its  inner  surface.  In  the  microscopic  examination  of 
organs  in  this  condition,  there  are  frequently  seen  films  of  such  exceeding  delicacy 
and  transparency  as  to  be  only  visible  by  very  careful  management  of  the  light :  they 
preserve  the  shape  of  the  tubules,  and  contain  no  nuclei  or  structures  of  any  kind. 
Similar  films  are  occasionally  seen  in  the  sediment  of  urine.  They  are  probably 
thrown  off  from  the  denuded  basement  membrane. 

"  Obliteration  of  the  Tubes. — The  basement  membrane,  which,  with  the  few  closely 
adherent  oval  nuclei  above  described,  is  now  the  sole  remaining  structure  of  the 
tubes,  soon  undergoes  a  change.  It  loses  the  cylindrical  form  proper  to  it  in  the 
fresh  and  natural  kidney,  and  becomes  flattened  by  the  pressure  of  the  surrounding 
parts.  Its  cavity  is  thus  obliterated,  and  what  was  a  tube  assumes  the  appearance 
of  a  transparent  riband,  dotted  here  and  there  with  small  oval  nuclei,  which,  when 
seen  at  the  edges,  appear  to  be  enclosed  between  twTo  layers  of  membrane.  These 
riband-shaped  portions  of  membrane  appear  to  present  considerable  tenacity  and  elas- 
ticity ;  by  their  greater  density,  and  by  the  constant  presence  of  the  small  oval  nuclei 
so  often  mentioned  between  their  layers,  they  are  in  most  cases  readily  distinguished 
from  the  delicate  films  which  have  been  referred  to  above.  They  are  very  various  in 
diameter,  but  are  always  inferior  in  this  respect  to  the  normal  tubes;  and  they  appear 
to  break  up  spontaneously  into  smaller  portions,  each  of  which  contains  from  one  to 
six  or  more  nuclei :  these  portions  are  of  various  sizes ;  they  are  usually  broadest  in 
the  middle,  and  taper  to  a  point  at  both  ends.     The  smallest  of  them  contain  only  a 


476  THE     SOLIDS. 

single  nucleus,  and  present  an  appearance  in  every  respect  like  that  of  young-  fibres 
of  areolar  texture,  or  those  fusiform  cells,  which  have  been  called  fibro-plastic.  I 
think  it  probable  that  the  whole  of  the  diseased  basement  membrane  ultimately  splits 
up  into  fibres  of  this  kind.  While  these  changes  are  proceeding,  the  capillary  vessels, 
which  have  ceased  to  be  subservient  to  secretion,  are  usually  obliterated :  the  conse- 
quence of  this  double  obliteration  of  vessels  and  tubes  is  a  considerable  degree  of 
atrophy  in  the  diseased  parts ;  and  as  the  atrophy  takes  place  at  first  chiefly  in  the 
cortical  substance,  great  irregularities  of  the  surface  generally  supervene :  thence 
arises  the  appearance  so  well  described  and  figured  by  Dr.  Bright  (Plate  EI.  fig.  2), 
in  which,  from  the  atrophy  of  the  cortical  substance,  the  bases  of  the  pyramids  '  are 
drawn  towards  the  surface  of  the  kidney.' 

"When  oleo-albuminous  exudation  supervenes  on  the  above  derangement  of  the 
tubes,  or  when  desquamation  supervenes  on  the  former  (circumstances  which  I  con- 
ceive to  be  of  very  common  occurrence),  the  exudation  most  commonly  takes  the 
form  of  the  granulations  of  Bright,  which  are  deposited  chiefly  in  the  diseased  tubes : 
and  the  atrophy  proceeding  around  these,  they  become  salient,  and  the  surface 
generally  irregular,  giving  rise  to  the  tuberculated  state  of  the  surface  so  common  in 
all  the  later  stages  of  the  granulated  kidney.  (Bright,  Plate  III.  fig.  1 ;  Rayer, 
Plate  VII.  fig.  6.  Plate  IX.  fig.  8.)  As  the  atrophy,  however,  proceeds,  the  granu- 
lations are  gradually  absorbed ;  and  when  the  kidney  has  become  extremely  con- 
tracted and  irregular,  they  often  in  part  disappear. 

"The  atrophied  portions  of  the  kidney  are  usually  ex-sanguine,  and  of  a  tawney  or 
drab  colour:  they  have  considerable  hardness  and  toughness.  Examined  microscopic- 
ally, they  appear  to  consist  of  fibres  and  fusiform  cells  in  great  abundance,  and  more  or 
less  granular  exudation,  according  to  circumstances.  According  to  Henle,  Eichholtz, 
Gluge,  and  others,  these  fibres  are  in  great  part  new  formations  ;  Johnson  and  Simon 
consider  them  as  nothing  more  than  the  compressed  parenchyma  of  the  gland,  from 
which  all  the  other  normal  elements  have  disappeared.  I  look  upon  them  as  formed 
in  great  part  by  the  breaking  up  of  the  basement  membrane  of  the  tubes  (as  above 
described),  as  well  as  from  the  parenchyma  and  obliterated  capillaries.  It  is  not 
improbable,  however,  that  in  addition  to  these  elements,  some  new  fibrous  tissue 
is  formed. 

"  The  extreme  stage  of  the  atrophied  kidney  is  nearly  the  same,  whether  exuda- 
tion have  existed  or  not. 

"Microscopic  Cyst-formation. — It  occasionally  happens,  on  examining  the  section 
of  a  kidney  with  the  microscope,  that  we  see,  scattered  through  some  parts  of  the 
section,  a  few  small  clear  vesicles,  of  nearly  circular  or  oval  form  :  they  are  either  of 
a  very  pale  straw-colour,  or  nearly  colourless,  and  are  perfectly  clear  and  translucent, 
with  a  very  distinct  shadowed  margin,  which  causes  them  to  stand  out  in  bold  relief 
from  the  other  textures  composing  the  section.  Their  diameter  is  usually  from  one- 
fortieth  to  one-fifteenth  of  a  millimetre,  but  in  this  respect  they  vary  considerably  ; 
sometimes  they  appear  to  lie  in  the  tubular  areolae,  and  at  other  times  to  be  uncon- 
nected with  these.  Very  rarely  they  have  appeared  to  contain  a  few  granules  ;  most 
commonly,  even  when  there  is  granular  exudation  around  them  on  every  side,  they 
contain  nothing  but  clear  fluid.     Their  refractive  power  is  not  so  great  as  that  of 


GLANDS.  477 

oil,  while  it  is  much  greater  than  that  of  the  spherical  cells  of  the  tubes:  hence  their 
distinct  and  characteristic  shadowed  outline. 

"  These  bodies  (which,  however,  have  never  appeared  to  me  to  present  distinct 
nuclei)  are  probably  the  same  with  the  '  nucleated  cells  or  vesicles'  described  by  Mr. 
Simon  as  resulting  from  the  extravasation  of  the  epithelial  cells  into  the  inter-tubular 
tissue,  and  as  progressively  enlarging,  so  as  to  form  the  cysts  visible  to  the  naked 
eye,  which  are  so  common  in  diseased  kidneys.  To  these  structures  he  attaches 
great  importance  in  the  pathology  of  the  kidney,  conceiving  them  to  be  the  invariable 
result  of  the  desquamative  disease  when  of  long  standing;  the  kidney  being,  in  Mr. 
Simon's  opinion,  changed  more  or  less  into  an  aggregation  of  microscopic  cysts, 
which  either  undergo  absorption,  and  lead  to  atrophy  of  the  organ,  or  increase  in 
size,  and  monopolize  its  texture.  Thus,  according  to  Mr.  Simon,  the  serous  cysts  so 
common  in  the  kidney  result  from  an  enormous  development  and  hypertrophy  of 
extravasated  epithelium  cells,  which  assume  the  character  of  the  vesicles  he  describes, 
and  acquire  the  power  of  increase  and  endogenous  development. 

"  Whether  the  bodies  described  by  me  above,  are  the  same  with  the  vesicles  of 
Mr.  Simon,  I  have  some  difficulty  in  determining :  but  they  are  the  only  objects  I 
have  seen  which  correspond  at  all  closely  with  his  description;  unless,  indeed,  it 
were  possible  to  suppose,  as  Dr.  Johnson  appears  to  hint,  that  he  may  have  mistaken 
the  normal  disposition  of  the  tubuli  for  a  cystic  structure. 

"  However  this  may  be,  I  am  satisfied  that  the  vesicles  above  described  are  excep- 
tional productions,  and  by  no  means  invariably  connected,  as  Mr.  Simon  describes 
his  vesicles  to  be,  with  the  progress  of  the  desquamative  degeneration.  They  are 
seen  in  comparatively  few  cases :  on  referring  to  four,  of  which  I  have  drawings  or 
memoranda,  I  find  two  to  have  been  congested  and  waxy  kidneys,  with  slight  exuda- 
tion; one  to  have  been  a  soft  and  desquamating  kidney,  also  with  slight  exudation; 
and  one  a  granular  kidney  with  numerous  cysts,  from  the  size  of  a  pea  to  that  of  a 
hazel-nut.  On  the  other  hand,  I  have  examined  organs  in  every  stage  of  desquama- 
tive disease  without  finding  these  bodies,  the  production  of  which  cannot  therefore 
be  an  essential  step  in  the  degeneration  and  atrophy  of  kidneys  so  affected. 

"  The  origin  and  progress  of  these  vesicles  is  very  obscure.  It  is  not  improbable 
that,  as  Mr.  Simon  asserts,  they  are  transformed  into  the  larger  cysts  visible  to  the 
naked  eye :  though  I  confess  that  I  have  not  been  able  to  trace  the  intermediate  steps 
of  their  progress  in  a  satisfactory  manner.  On  the  other  hand,  their  origin  from 
extravasated  epithelial  cells  seems  exceedingly  improbable ;  indeed,  I  have  already 
stated,  that  I  do  not  think  the  epithelium  ever  becomes  extravasated.  Moreover,  the 
vesicles  in  question  have  all  the  appearance  of  being  formed  within  the  tubes, 
although  they  afterwards  become  separated  from  them. 

"  From  the  occasional  appearances  of  alternate  distention  and  constriction  pre- 
sented by  the  tubes  when  undergoing  obliteration,  I  am  induced  to  believe  that  cysts 
may  be  formed  by  the  occlusion  and  isolation  of  portions  of  tube  which  have  not  yet 
lost  their  power  of  secretion.  Whether  the  vesicles  in  question  are  formed  in  this 
way,  can  only  be  determined  by  close  and  repeated  observation  ;  and  I  have  not  been 
able  to  obtain  demonstrative  evidence  on  this  point. 

"  The  larger  cysts  in  the  kidney  present  very  strong  evidence  of  being  formed  in 
connexion  with  the  secreting  membrane.     In  one  instance,  I  found  their  inner  surface 


478  THE     SOLIDS. 

to  be  lined  at  some  points  with  tessellated  epithelium,  in  the  form  of  pentagonal  or 
hexagonal  flattened  cells,  with  circular  nuclei;  in  another  case,  there  were  oval 
nuclei  without  any  distinct  cells,  and  a  large  number  of  free  oil  globules  of  consider- 
able size.  The  existence  of  oil  in  these  cysts  has  also  been  observed  by  Dr.  Johnson. 
Other  products  of  secretion  are  also  occasionally  found.  On  one  occasion  I  found 
several  cysts  in  a  kidney,  otherwise  healthy  in  appearance,  which  contained  a  turbid 
ochrey-coloured  liquid,  presenting  under  the  microscope  numerous  minute  crystals 
of  uric  acid.  Mr.  Simon  mentions  having  found  on  two  occasions  xanthic  oxyde  in 
considerable  proportion.  I  have  more  than  once  observed  them  to  contain  blood  hi 
large  quantity;  and  I  have  likewise  found  them  full  of  a  matter  like  stiff  glue. 

"  The  occurrence  of  cysts  in  kidneys  presenting  a  generally  healthy  structure  is  so 
frequent,  as  to  lead  to  the  idea  that  they  must  be  in  such  cases  the  result  of  disease 
which  has  been  arrested  before  any  considerable  disorganization  has  taken  place. 
Many  of  the  cases  of  partial  atrophy  of  the  kidneys  figured  by  Rayer  are  probably 
due  to  the  rupture  or  obliteration  of  these  cysts. 

"Before  leaving  the  subject  of  cyst-formation,  I  may  state,  that  in  one  instance  I 
have  observed  the  Malpighian  capsules  to  be  occupied  by  distinct  cysts.* 

"  Dilatation  and  Thickening  of  the  Tuhes. — This  condition,  although  by  no  means 
a  very  frequent  one,  is  important,  as  being  characteristic,  so  far  as  I  have  observed, 
of  the  extreme  stage  of  what  I  have  called  the  '  waxy  degeneration.'  I  have  scarcely 
ever  seen  it  unaccompanied  by  entire  obliteration  of  the  vessels,  and  by  enlargement 
and  increased  density  of  the  kidney.  The  organ  has  the  dense  resistant  feeling  of 
fibro-cartilage,  and  both  cortical  and  tubular  portions  have  the  light  yellow  colour, 
and  the  appearances  described  above  as  those  of  the  waxy  degeneration  in  its  last 
stage.  The  striee  of  the  pyramids  appear  to  radiate  indefinitely  towards  the  surface, 
and  meet  the  cortical  substance  in  digitations,  instead  of  being  marked  off  by  a  sharp 
semi-circular  line,  as  occurs  in  the  healthy  kidney.  When  examined  with  a  simple 
lens,  or  even  the  naked  eye,  the  pyramidal  stria)  are  seen  to  pursue  an  unusually 
sinuous  course:  this  is  peculiarly  the  case  where  they  pass  into  the  cortical  substance. 

"Moreover,  the  pyramids  are  unusually  broad  at  the  bases;  and  the  length  of  the 
straggling  digitations  is  sometimes  so  great,  that  I  have  measured  fully  an  inch  and 
a  half  between  the  extreme  end  of  the  strke  and  the  corresponding  papilla.  Never- 
theless, the  cortical  substance  is  not  usually  diminished  in  quantity,  being  developed 
to  a  great  extent  between  the  pyramids. 

"  This  condition  I  have  ascertained  to  proceed  from  dilatation  and  thickening  of 
the  tubuli  uriniferi  throughout  the  organ.  The  dilated  tubes  are  usually  twisted  and 
varicose,  as  may  be  seen  by  inspecting  a  section  of  the  pyramids  with  a  low  power. 
When  examined  with  a  higher  power,  the  section  presents  an  appearance  very  similar 
to  some  tumours  (of  the  fibrous  or  fibro-cysted  kinds),  viz :  a  number  of  compressed 
areolae,  enclosed  by  fibrous  tissue,  and  presenting  an  appearance  of  irregular  con- 
centric rings,  of  various  distinctness,  (an  effect  apparently  due  to  the  peculiar  refrac- 

*  Obs.  In  one  case  of  cystic  disease  of  the  kidneys  which  fell  under  the  notice  of 
Mr.  Quekett,  the  formation  of  the  cysts  evidently  commenced  in  the  corpora  Mal- 
pighiana  beneath  the  capillary  plexus. — A.  H.  H. 


GLANDS.  479 

tion  of  light  by  the  thickened  membrane.)  The  nuclei  are  obscured  or  invisible 
owing  to  the  thicknass  of  the  intervening  wall,  but  nevertheless  exist  in  considerable 
numbers.  The  Malpighian  bodies  and  capillaries  are  usually  obliterated.  The  kidney 
nas  in  fact  become,  like  the  tumours  whose  structure  it  resembles,  a  true  non- 
vascular texture. 

"  The  explanation  of  the  peculiar  extension  of  the  pyramidal  strise  towards  the 
surface  in  these  cases,  is  to  be  found  in  the  fact  that,  even  in  the  normal  condition, 
the  convoluted,  tubuli  have  a  general  disposition  from  the  bases  of  the  pyramids 
towards  the  surface,  in  the  direction  of  the  strise  of  the  cones.  This  is  evident  from 
the  facility  with  which  the  gland  tears  in  that  direction;  although  in  the  normal  state 
this  disposition  is  masked  by  that  of  the  vessels,  which,  passing  in  straight  lines 
through  the  cones,  break  into  a  complicated  net-work  of  capillaries  at  the  bases  of 
the  pyramids.  In  the  present  lesinn,  the  vessels  having  disappeared,  and  the  course 
of  tubes  being  strongly  marked,  their  disposition  towards  the  surface  becomes  mani- 
fest, and  the  abrupt  line  of  demarcation  between  the  cortical  and  pyramidal  substance, 
caused  by  the  presence  of  the  vessels,  is  obliterated." 


CONCLUSION. 

With  the  view  of  enabling  the  reader  to  place  the  foregoing  observations  in 
relation  with  the  descriptions  found  in  systematic  pathological  works,  Dr.  Gairdner 
subjoins  the  following  short  remarks  on  the  principal  physical  characters  usually 
ascribed  to  diseased  kidneys : 

"  Increase  of  Size  and  Weight :  Hypertrophy. — Enlargement  of  the  kidney  occurs 
chiefly  in  consequence  of  three  conditions: — 1st,  from  sanguineous  engorgement;  2d, 
from  distention  of  the  tubes  by  secretion  or  exudation;  3d,  from  permanent  dilatation 
and  thickening  of  the  tubes.  Of  all  these  causes,  the  second  is  by  far  the  most 
common.     The  last  is  characteristic  of  the  waxy  degeneration  formerly  described. 

"The  quantity  of  liquid  in  the  tubes  is,  at  all  times,  subject  to  so  much  variation, 
that  it  is  difficult  to  say  what  amount  of  increase  of  weight  may  be  thereby  occasioned 
without  the  existence  of  any  positively  morbid  condition.  It  is  not  very  uncommon 
to  find  kidneys,  otherwise  not  differing  from  the  healthy  standard,  about  double  the 
usual  weight,  or  between  seven  and  eight  ounces  each.  I  have  more  than  once  found 
them  to  weigh  nine  ounces  each,  with  very  slight  marks  of  disease.  When  the  weight 
much  exceeds  this,  it  is  probable  it  arises  from  the  rare  combination  of  vascular  and 
tubular  engorgement. 

"  In  kidneys  containing  oleo-albuminous  exudation,  the  greatest  increase  of  size  is 
attained,  when  the  exudation  is  universal,  and  unaccompanied  by  desquamation. 

"Cystic  degeneration  of  the  kidneys,  dilatation  of  the  pelvis  and  ureters  (Hydro- 
ntphrose,  Rayer),  &c,  also  give  rise  to  great  increase  of  size  and  weight. 

"Diminution  of  Size  and  Weight:  Atrophy.— This  condition  sometimes  occurs  to 
a  certain  extent,  in  emaciated  subjects,  without  any  disorganization,  owing  to  the 


480  THE     SOLIDS. 

diminished  activity  of  secretion.  More  frequently,  however,  it  is  the  result  of  sepa- 
ration of  the  epithelium,  followed  by  contraction  and  obliteration  of  the  tubular 
structure. 

"  Atrophy,  from  this  cause,  is  liable  to  supervene  in  all  other  varieties  of  renal 
lesion,  except  the  waxy  degeneration,  which  appears  to  lead  to  a  permanently  hyper- 
trophied  condition  of  the  organ.  In  kidneys  enlarged  from  exudation,  the  occurrence 
of  desquamation  and  its  consequences  is  frequent ;  and  the  diminution  of  size  in 
such  cases  is  often  not  followed  by  a  return  to  the  natural  condition,  but  by  perma- 
nent atrophy. 

"  The  course  of  all  disorganizing  diseases  of  the  kidney  is  to  produce  first,  enlarge- 
ment, and  then  contraction  of  the  organ.  In  the  extreme  stages  of  the  atrophy 
which  results  from  exudation,  exudation  is  often  nearly  absent.  When  exudation, 
therefore,  even  in  very  sparing  quantity,  accompanies  a  contracted  condition  of  the 
kidney,  there  is  a  probability  that  it  has  been  abundant  at  some  former  period. 

"  Irregularities  of  Surface :  Tuberculated  and  Granulated  Kidneys. — The  smooth- 
ness of  the  surface  in  the  kidney  is  destroyed  either  by  unequal  dilatation  or  unequal 
contraction  of  the  tubili  of  the  cortical  substance.  The  former  takes  place  in  the 
waxy  degeneration ;  the  latter,  in  the  desquamative  processes. 

"  The  most  frequent  irregularities  of  surface  are  formed  in  connexion  with  the 
granulations  of  Bright.  These  are  invariably  formed  when  exudation  is  deposited 
in  kidneys  tending  to  the  desquamative  lesion ;  and,  as  this  runs  its  usual  course,  the 
granulations  become  prominent  from  the  destruction  of  the  tubes  around  them.  An 
extreme  degree  of  the  irregularities  thus  produced,  constitutes  the  tuberculated 
kidney. 

"  The  puckering  and  partial  atrophy  occasionally  seen  in  kidneys,  otherwise  not 
morbid,  or  comparatively  slightly  diseased,  are  probably,  in  many  instances,  the 
result  of  the  obliteration  of  cysts. 

"The  more  remarkable  changes  in  colour  and  consistence  are  described  very  fully 
in  many  parts  of  the  preceding  memoir." 

On  reviewing  the  whole  of  the  preceding  observations,  Dr.  Gairdner  is  induced  to 
regard  the  following  conclusions  as  especially  important  in  relation  to  the  pathology 
of  renal  diseases: 

"1.  By  far  the  greater  part  of  the  pathological  lesions  of  the  kidney  arise  from,  or 
are  connected  with,  the  exudation  of  oleo-albuminous  granules  into  the  interior  of 
the  tubes  and  epithelial  cells. 

"  2.  The  oleo-albuminous  exudation  is,  probably,  often  preceded,  and,  certainly, 
occasionally  accompanied,  by  vascular  congestion ;  but  when  the  quantity  of  exuda- 
tion is  considerable,  more  or  less  complete  depletion  of  the  vascular  system  invariably 
occurs.    This  is  a  secondary  result  of  the  obstruction  of  the  lubuli  uriniferi. 

"  3.  The  oleo-albuminous  exudation  occurs  in  two  chief  forms,  viz :  first,  universal 
infiltration  of  the  tubes  throughout  the  organ ;  and,  second,  infiltration  of  peculiar 


GLANDS.  481 

sets  of  tubules :  the  rest  remaining  free,  or  nearly  so.    In  the  latter  mode  arise  the 
granulations  of  Bright. 

"  4.  There  is  no  essential  anatomical  difference  between  the  exudations  in  the  kid- 
ney, which  are  the  result  of  chronic  processes,  and  those  which  have  been  considered 
as  the  result  of  inflammation. 

"  5.  The  capillary  vessels  of  the  kidney  are  subject  to  spontaneous  obliteration 
(unaccompanied,  in  the  first  instance,  by  any  visible  lesion  of  the  tubes),  giving  rise 
to  the  peculiar  affection  which  I  have  called  the  waxy  degeneration.  This  oblitera- 
tion of  the  vessels  is  probably,  in  all  cases,  preceded  by  a  stage  of  congestion. 

"  6.  The  consequence  of  the  waxy  degeneration  is  thickening  and  varicose  dilata- 
tion of  the  tubuli  throughout  the  organ. 

"  7.  The  tubes  of  the  kidney  are  subject  to  contraction  and  obliteration,  in  conse- 
quence of  the  desquamation  of  their  epithelium;  a  condition  resulting  in  atrophy,  and 
complete  disorganization  of  the  organ. 

"  8.  The  desquamation  of  the  epithelium  occurs  very  frequently  in  all  the  other  dis- 
eased conditions  of  the  kidney.  When  sufficiently  long-continued  and  extensive,  it 
produces  contraction,  and  this  indifferently,  whether  exudation  be  present  or  not.  It 
is  sometimes  accompanied  by  vascular  congestion  in  every  stage  of  its  progress. 

"  9.  The  earlier  stages  of  the  exudations  can  only  be  discovered  by  means  of  the 
microscope.  The  progress  of  the  waxy  degeneration,  on  the  contrary,  is  best  traced 
by  the  unaided  eye.  The  desquamation  of  the  epithelium  is  only  to  be  discovered 
with  certainty  by  means  of  the  microscope,  and  is  particularly  apt  to  escape  attention, 
under  all  circumstances,  if  the  kidney  only,  and  not  the  urine,  be  looked  to.  It  results 
that  careful  investigation,  both  by  the  microscope  and  the  naked  eye,  both  of  the 
kidney  after  death  and  the  urine  during  life,  are  indispensable,  to  enable  the  patholo- 
gist to  determine  with  exactitude  the  presence  or  absence  of  disease." 

I  have  been  induced  to  dwell  thus  largely  on  the  microscopic 
pathology"  of  the  kidney:  first,  on  account  of  the  great  importance 
and  interest  attached  to  the  lesions  of  that  organ ;  secondly,  from  the 
great  number  of  interesting  facts  which  the  microscope  has  already 
brought  to  light  in  reference  to  its  pathology ;  and,  thirdly,  in  the 
hope  of  inducing  other  observers  to  follow  out  more  completely  the 
inquiry  which  has  already  led  to  such  successful  and  striking  results. 

31 


482  THE     SOLIDS, 


KIDNEY. 

[The  anatomy  of  the  kidney  may  be  in  part  studied  by  dissection  of 
recent  specimens  under  water.  The  structure,  however,  is  more  readily 
made  out  after  injection,  and  this  is  best  performed  after  removal  from  the 
body.  An  injection  by  either  set  of  vessels  almost  always  passes  into  the 
others.  Hence  an  injection  by  the  artery  frequently  fills  partially  the 
tubule  uriniferi  and  the  veins.  It  will  be  exceedingly  difficult  to  limit  the 
injection  to  the  terminations  of  the  vessel  injected ;  many  trials,  however, 
will  enable  one  to  judge  how  much  force  is  necessary  to  fill  only  the  set  of 
vessels  desired. 

When  three  colours  can  be  successfully  employed,  the  best  arrangement 
will  be  found  to  be — red  or  blue  for  the  arteries,  yellow  for  the  veins,  and 
white  for  the  urinary  tubes.  When  it  is  required  to  fill  the  three  sets  of 
vessels  with  one  injection,  the  artery  must  be  first  injected,  and  the  urinif- 
erous  tubes  farther  filled  from  the  ureter.  It  may  be  here  stated,  that  for 
practise  in  making  fine  injections,  the  kidneys  of  sheep,  pigs,  &c,  will  be 
found  the  organs  most  suitable  for  that  purpose.  They  are  easily  obtained, 
are  sufficiently  difficult  to  inject,  and  do  not  require  a  very  large  amount 
of  material. 

Injections  of  the  kidneys  are  best  preserved  in  Canada  balsam  without 
heat,  after  being  cut  in  slices,  and  dried.  Cells  may  be  used  or  not, 
according  to  the  thickness  of  the  specimen. 

Plate  LXXV.    fig.  5,  Malpighian  bodies  and  their  relation  to  the  urinif- 
erous  tubes, 
fig.  6,  The  same  enlarged,  as  in  the  first  stage  of  Bright's 
disease. 
Plate  LXXVI.    fig.  1,  Enlarged  veins  of  kidney. 
"       fig.  2,  The  same  ;  another  view. 
"       fig.  3,  Stellated  condition  of  veins. 
"       fig.  4,  Granulation  on  the  surface  of  the  kidney. 
"      fig.  5,  A  tube  much  dilated.] 


GLANDS.  483 


The  testis,  the  last  of  the  tubular  glands  in  the  human  subject, 
agrees  more  closely  in  structure  with  the  sudoriferous  and  ceruminous 
glands  than  with  the  kidney;  there  being  this  in  common  between  the 
three  first  mentioned,  viz :  that  the  tubes,  of  which  they  are  principally 
constituted,  are  convoluted,  and  are  not  enclosed  in  a  dense  frame- 
work of  fibro-elastic  tissue,  as  is  the  case  with  those  of  the  kidney. 

The  testis,  is  invested  by  a  tunic  of  white  fibrous  tissue;  this  sends 
down,  into  the  substance  of  the  gland,  numerous  dissepiments,  which 
divide  the  tubes  of  which  it  is  composed  into  parcels,  each  of  which 
may  be  called  a  lobe. 

The  tubes  of  the  testes  are  remarkable  for  their  large  size,  great 
tortuosity,  and  exceeding  and  ready  extensibility.  (See  Plate  LX. 
figs.  1.4.) 

When  viewed  as  opaque  objects,  the  tubes  appear  of  a  delicate 
and  semi-transparent  whiteness;  and,  when  seen  by  transmitted  light, 
they  are  almost  black;  this  arises  from  the  fact  of  the  interception 
of  the  luminous  rays  by  the  cells  contained  within  the  tubes. 

The  membrane  of  the  tubes  is  totally  distinct  from  that  of  most 
other  tubular  glands;  it  is  very  thick  and  fibrous,  being  constituted 
of  a  well-marked  form  of  nucleated  fibro-elastic  tissue.  (See  Plate 
LX.^.4.) 

The  constitution  of  the  tubes  of  elastic  tissue  explains  satisfactorily 
their  ready  extensibility  and  variable  diameter;  this  variation,  in 
specimens  prepared  for  microscopic  examination,  is  very  obvious,  and 
arises  from  the  displacement  of  the  contained  cells,  occasioned  by 
unequal  external  pressure;  where  these  cells  are  accumulated  in  the 
greatest  number,  there  the  tubes  are  thickest ;  and  where  there  are 
but  few  cells,  or  even  where  the  tubes  are  destitute  of  cells,  they  are 
thinnest,  and  frequently  even  entirely  collapsed. 

These  facts  show  that  the  tubes  are  highly  expansive;  and  there  is 
no  doubt  that  their  diameter  varies,  during  life,  in  accordance  with 
the  amount  of  seminal  fluid  contained  within  the  testis;  this  expansive 
property  being  especially  designed  to  allow  of  the  accumulation  of 
that  fluid  within  the  semeniferous  organ. 

The  tubes  of  the  testis  contain  a  vast  number  of  granular  cells  of 
various  sizes  (see  Plate  LX.  jig.  4),  some  being  several  times  larger 
than  others,  especially  in  the  testis  of  the  adult.  Most  of  these  cells 
contain  but  a  single  nucleus ;  in  others,  however,  and  these  the  larger 


484  THE     S0LID3. 

cells,  there  are  as  many  as  from  two  to  seven,  or  even  more,  distinct 
nuclei.     (See  Plate  XVI.  fig.  1.) 

In  the  testes  of  a  child,  the  granular  cells  present  great  uniformity 
of  size,  and  contain,  for  the  most  part,  but  a  single  nucleus.  These 
cells,  as  in  other  tubular  glands,  form  a  regular  epithelium  on  the  walls 
of  the  tubes,  the  central  channel  being  free ;  this  arrangement  is  very 
evident  in  the  tubes  of  immature  testes ;  but  far  less  so  in  those  of 
the  adult  organ;  the  manipulation  to  which  the  latter  are  subject,  when 
being  prepared  for  microscopical  observation,  readily  displacing  the 
cells. 

It  is  in  these  cells,  according  to  the  observations  of  numerous 
observers,  that  the  spermatozoa  are  developed.  For  further  particu- 
lars on  the  development  of  the  spermatic  animalcules,  see  the  article 
"Semen" 

The  tubes  of  the  testes  are  loosely  bound  together  by  bands  of 
fibrous  tissue;  it  is  this  tissue  which  contains  the  tortuous  blood- 
vessels with  which  this  organ  is  so  copiously  supplied. 

That  the  tubes  are  not  furnished  with  a  distinct  external  envelope, 
like  those  belonging  to  the  kidney,  is  proved  by  the  fact  that  they 
admit  readily  of  being  separated  from  each  other,  as  also  of  being 
drawn  out  to  a  great  length :  this  last  circumstance  shows  the  extent 
to  which  the  tubes  are  convoluted,  the  few  anastomoses  which  take 
place  between  them,  and  their  extraordinary  elasticity. 

VASCULAK    GLANDS, 

The  vascular  glands  all  agree  with  each  other  in  the  abscence  of 
excretory  ducts  or  channels  for  the  discharge  of  their  secretion,  a 
deficiency  which  involves  as  a  necessary  consequence  the  reception 
of  the  secreted  fluids  by  the  blood-vessels. 

From  the  differences  in  the  size  and  structure  of  these  several  glands, 
it  is  very  doubtful  whether  any  other  resemblance  besides  that  just 
pointed  but  exists  between  them,  and  it  is  most  probable  that  each  has 
a  separate  purpose  to  fulfil  in  the  animal  economy. 

THYMUS. 

The  thymus,  although  usually  spoken  of  and  described  as  a  single 
organ,  is  in  reality  double,  and  consists  of  two  distinct  glands  united 
to  each  other  in  the  middle  line  by  cellular  tissue  only. 

Each  separate  adult  thymus  is  constituted  of  numerous,  probably 


GLANDS.  485 

some  hundred  follicles,  which  vary  in  size  from  a  pin's  head  to,  in 
some  cases,  that  of  a  pea,  and  the  walls  of  which  are  made  up  of 
mixed  fibrous  tissue. 

These  follicles  are  usually  more  or  less  rounded,  but  sometimes 
polygonal  in  shape  from  pressure;  they  are  loosely  held  together  by 
fibrous  tissue,  and  by  the  blood-vessels  which  supply  them ;  they  each 
contain  in  their  interior  a  cavity  which  is  more  or  less  filled  with  a 
milky  fluid.     (See  Plate  LXI.  fig.  8.) 

Several  of  these  follicles  open  into  each  other  and  into  a  common 
receptacle  or  "pouch,"  and  this  last  again  opens  into  the  internal 
cavity  of  the  gland,  the  face  of  which  is  thickly  studded  with  similar 
openings. 

On  its  exterior  each  follicle  may  be  seen,  even  without  injection,  to 
be  invested  with  a  very  beautiful  plexus  of  blood-vessels,  represented 
in  Plate  LXI.  fig.  8. 

When  unravelled  by  the  removal  of  the  inter-lobular  cellular  tissue, 
the  whole  gland  is  seen  to  consist  of  a  straight  tube,  with  the  follicles 
arranged  around  it  in  a  spiral  manner. 

The  central  cavity,  "  reservoir  of  thymus,"  is  lined  by  a  delicate 
mucous  membrane,  which  is  raised  into  ridges  by  a  layer  of  ligament- 
ous bands  situate  beneath  it;  these  proceed  in  various  directions,  and 
encircle  the  apertures  of  the  pouches :  their  use  is  to  keep  the  lobules 
together,  and  to  prevent  the  injurious  distention  of  the  cavity. 

The  whole  organ  is  enclosed  in  a  dense  capsule  of  fibrous  tissue, 
the  blood-vessels  contained  in  which  are  remarkable  for  their  disposi- 
tion in  three's,  an  arrangement  which  is  not  uncommon  in  the  capsular 
investments  of  glands.     (See  Plate  LXI.  fig.  7.) 

The  "milky  fluid"  contained  in  the  follicles  and  reservoir  is  made 
up,  to  a  great  extent,  of  an  immense  number  of  granular  nuclei,  as 
well  as  numerous  cells  of  large  size,  which  do  not  appear  hitherto 
to  have  been  either  described  or  figured  in  a  satisfactory  manner,  and 
which  are  probably  to  be  regarded  in  the  light  of  parent  cells.  (See 
Plate  LXI.  fig.  10.) 

Many  of  these  cells  contain  several  granular  nuclei,  each  of  which 
is  surrounded  by  one  or  more  concentric  lamellae ;  they  thus  resemble 
the  cartilage  cells  found  in  the  inter- vertebral  substance,  and  also 
certain  species  of  Microcystis,  a  genus  of  Fresh- water  Algae. 

Mr.  Simon,  in  his  "Prize  Essay,"  makes  the  following  observations 
on  the  above-described  cells : — "  In  specimens  taken  from  animals  past 
that  period  of  life  when  the  thymus  is  most  active,  I  have  found  cells 


486  THE     SOLIDS. 

in  which  these  dotted  corpuscles  occupied  the  relation  of  nuclei.  The 
cells  are  at  first  little  larger  than  the  corpuscles  themselves,  and  contain 
a  perfectly  pellucid  material;  but  as  they  grow,  their  contents  become 
molecular,  and  they  develope  themselves  into  perfect  fat  cells,  which 
lie  in  the  cavities  of  the  glands,  and  in  some  instances  completely 
fill  them.  During  the  period  in  which  these  cells  are  being  developed, 
the  application  of  acetic  acid  to  the  preparation  as  it  lies  under  the 
microscope  shows  them  to  have  great  affinity  to  embryonic  cells;  for 
the  acid  dissolves  the  cell-membrane  completely  away,  and  leaves  the 
nucleus  of  the  cell  (the  dotted  corpuscle)  unaffected  by  its  action." 

Lining  each  follicle,  Mr.  Simon  has  detected  a  delicate  and  homo- 
geneous structure,  which  he  has  termed  the  "  limitary  membrane  :" 
this  structure  is  identical  with  the  basement  membrane  of  Bowman, 
and  is  probably  common  to  all  glands,  especially  the  follicular  ones. 

Mr.  Simon  has  likewise  described  a  lobular  arrangement  of  the  fol- 
licles. The  structure  of  the  gland  resolves  itself,  he  says,  "into 
masses  ranged  round  an  axis.  Each  mass  constitutes  a  sort  of  cone 
of  glandular  substance,  its  apex  pointing  to  the  axis  or  mesial  line  of 
the  gland;  its  base  directed  to  the  surface,  where  it  presents  innumer- 
able vesicles;  while  its  intermediate  part  contains  those  successive 
branchings  of  the  follicle  which  terminate  superficially  in  the  vesicu- 
lar form." 

THYROID    GLAND. 

The  anatomy  of  this  gland  is  best  studied  in  a  specimen  which  has 
undergone  a  slight  enlargement  of  its  several  parts;  a  portion  of  such 
a  gland,  when  viewed,  with  the  inch  object-glass,  bears  so  close  a 
resemblance  to  a  mass  of  fat,  that,  except  by  a  practised  miscroscopist, 
it  would  be  impossible  to  distinguish  it  therefrom  with  such  a  low 
power;  even  when  viewed  with  the  half-inch,  the  illusion  would 
scarcely  be  dispelled,  and  it  is  only  on  the  application  of  the  quarter- 
inch  glass,  that  misgivings  would  begin  to  be  entertained  in  reference 
to  its  identity  with  fat. 

The  resemblance  borne  by  a  portion  of  thyroid  gland  thus  slightly 
enlarged  by  disease  to  a  mass  of  fat,  arises  from  the  form  of  the  ves- 
icles or  closed  cells  of  which  the  gland  is  composed,  and  from  the 
manner  in  which  they  reflect  the  light,  the  centre  of  each  vesicle 
being  clear  and  bright,  and  the  circumference  dark  and  almost  black; 
here,  however,  the  resemblance  ceases,  as  the  thyroid  vesicles  are 
most  satisfactorily  distinguished  from  fat  globules  by  their  larger  size, 
the  fibrous  texture  of  their  parietes,  and  the  nature  of  their  contents. 


GLANDS.  487 

Such  is  the  general  character  and  appearance  of  a  portion  of 
thyroid  examined  microscopically;  the  entire  gland,  however,  consists 
of  two  lobes,  which  are  placed  one  on  each  side  of  the  trachea,  and 
which  are  connected  with  each  other  by  a  narrow  slip,  or  isthmus  of 
the  gland,  and  these  lobes  are  further  divisible  into  numerous  lobules, 
many  hundreds  to  each  lobe.  Now,  it  is  these  lobules  which,  so  far 
as  the  descriptions  hitherto  given  of  this  gland  are  to  be  understood, 
have  been  regarded  and  described  as  the  membranous  cavities  of 
the  thyroid  (see  Plate  LXI.  fig.  1),  the  true  and  ultimate  cellular 
structure  being  in  general  overlooked. 

Thus  the  lobules  are  further  divisible,  each  into  many  small 
cavities,  the  ultimate  divisions  of  which  the  gland  is  susceptible.  (See 
Plate  LXI.  figs.  2,  3,  4,  5.)  These  in  the  slightly  enlarged  gland 
are  circular,  and  comparable  to  fat  vesicles  (see  Plate  LXI.  figs.  2, 
3) ;  but  in  the  gland  in  its  normal  state,  they  are  compressed  and 
angular,  being  also  very  liable  to  be  altogether  overlooked,  their  size 
and  form  being  indicated  only  by  certain  light-coloured  spaces 
traversing  the  lobule.     (See  Plate  LXI.  fig.  5.) 

Over  the  surface  of  each  lobule,  the  blood-vessels  form  a  plexus, 
from  which  branches  proceed  inwards,  encircling  the  vesicles  much 
in  the  same  way  as  the  blood-vessels  do  the  fat  corpuscles.  (See 
Plate  LXI.  fig.  1.) 

The  cavity  of  each  vesicle  is  perfectly  distinct,  and  does  not  com- 
municate with  that  of  any  other  of  the  vesicles  by  which  it  is 
surrounded:  the  fibrous  tissue,  however,  of  which  its  walls  are  so 
evidently  composed  (Plate  LXI.  fig.  4),  does  communicate  with  and 
run  into  that  of  the  neighbouring  vesicles,  at  certain  points,  however, 
only.  These  fibres  may  frequently  be  traced  from  the  wall  of  one 
cell  into  that  of  another;  and  it  is  this  fibrous  union  of  the  vesicles 
which  renders  it  impossible  completely  to  isolate  any  one  of  the  cells, 
and  accounts  for  the  fact,  that  when  the  vesicles  are  broken  up  with 
needles,  they  are  entirely  reduced  to  fibrous  tissue. 

The  contents  of  the  vesicles  consist  of  a  fluid,  containing  numerous 
granular  nuclei  of  a  rounded  or  oval  form,  as  well  as  of  a  few  perfect 
cells,  two  or  three  times  larger  than  the  nuclei,  and  the  granules 
contained  in  which  are  very  large,  presentingan  oily  aspect;  between 
these  two  extremes  of  size,  other  cells  intermediate  are  met  with:  the 
larger  are  evidently  parent  cells.     (See  Plate  LXI.  figs.  9  and  4.) 

The  fluid  of  the  vesicles  contains  a  good  deal  of  oil,  which,  when 
the  gland  is  slightly  decomposed,  is  apt  to  collect  in  them  in  the  form 
of  one  or  two  lame  circular  discs. 


488  THE     SOLIDS. 

The  increase  in  the  size  of  the  gland  in  goitre  is  due  to  an  increased 
development  of  the  vesicles  and  of  their  contents. 

It  is  evident  that  each  vesicle  contains  all  the  elements  of  the  gland, 
and  that  the  entire  organ  is  made  up  of  an  assemblage  of  many  thou- 
sands of  such  vesicles  or  glands.     (See  Plate  LXI.  fig.  2.) 

SUPRA-RENAL    CAPSULES. 

The  supra-renal  capsule  bears  some  resemblance  in  structure  to  the 
kidney,  being  divisible  like  it  into  a  cortical  and  medullary  substance. 

It  is  made  up  of  numerous  simple  and  cylindrical  tubes,  closed  at 
both  ends,  and  formed  of  structureless  basement  membrane;  these 
tubes  are  disposed  in  a  vertical  manner,  one  extremity  forming  the 
surface  of  the  organ,  and  the  other  extending  in  an  opposite  direction, 
as  far  as  the  inner  cavities  or  lacunae  situated  in  the  centre  of  each 
supra-renal  capsule.     (See  Plate  LX.ll.  Jig.  3  a.) 

These  tubes  enclose  elements  of  three  kinds;  first,  innumerable 
circular  particles  or  molecules,  which  reflect  the  light  strongly,  and 
which  are  of  an  oily  nature;  of  these  the  greater  part  is  free  in  the 
tubes,  but  a  lesser  proportion  is  enclosed  in  certain  of  the  cells  which 
are  met  with  in  the  tubes ;  second,  granular  nuclei  in  large  quantities ; 
and,  third,  parent  cells  of  considerable  size,  containing  each  several 
nuclei  intermingled  with,  and  in  part  very  frequently  obscured  by  a 
considerable  number  of  the  bright  molecules  previously  referred  to. 
These  parent  cells  do  not  appear  to  have  been  hitherto  characterized 
with  any  degree  of  precision.     (See  Plate  LXII.  fig.  3  b.) 

The  differences  between  the  cortical  and  medullary  portions  of  the 
supra-renal  capsule,  depend  principally  upon  the  irregular  disposition 
of  the  tubes  in  the  latter,  the  plexiform  arrangement  of  the  vessels, 
and  on  the  presence  of  numerous  parent  cells  containing  more  or  less 
of  colouring  matter  in  their  interior.  It  is  these  cells  which  impart 
to  sections  of  the  gland  the  dotted  appearance  so  commonly  observed 
in  its  medullary  portion.     (See  Plate  LXII.  fig.  3.) 

The  vascular  distribution  in  the  supra-renal  is  very  simple.  On 
the  surface  of  the  organ  we  have  a  very  beautiful  plexus  of  capillaries, 
the  pentagonal  and  hexagonal  meshes  of  which  lie  in  the  intervals 
between  the  extremities  of  the  tubes ;  in  the  tubular  part  the  vessels, 
both  veins  and  arteries  run,  in  straight  lines  between  the  tubules, 
terminating,  on  the  one  hand,  in  the  plexus  on  the  surface,  and,  on 
the  other,  in  the  central  plexus.     (See  Plate  LXII.  figs.  1.  5.) 

The  supra-renal  is  an  organ  which  varies  greatly  in  different  sub- 


GLANDS.  489 

jects;  in  some  the  proportion  of  granules  is  much  greater  than  in 
others ;  in  others  again,  the  central  lacunae  are  occupied  with  a 
whitish-looking  substance,  which,  on  examination,  is  found  to  consist 
of  granular  nuclei  arranged  in  irregular  masses,  but  in  which  some- 
times we  can  detect  a  tubular  disposition:  in  these  cases  we  encounter 
from  without  inwards,  three  substances ;  cortical,  medullary,  and  then 
lastly,  the  central  substance  just  described. 

The  capsule  of  the  supra- renal  is  often  laden  with  fat,  which  totally 
.  obscures  the  plexus  on  the  surface  of  the  organ. 

The  parent  cells,  when  filled  with  oily  molecules,  bear  a  close' 
resemblance  to  the  cells  of  a  sebaceous  gland,  between  which  and  the 
supra-renal  capsule  one  would  hence  be  disposed  to  suspect  a  degree 
of  affinity. 

SPLEEN. 

The  spleen  consists  of  a  fibro-elastic  capsule  which  sends  down 
from  its  inner  surface  septa,  which  penetrate  the  organ  in  all  direc- 
tions, and  divide  it  into  compartments;  of  an  immense  assemblage  of 
blood-vessels  which  compose  its  chief  substance,  and  which  impart  to 
it  the  character  and  appearance  of  an  erectile  tissue ;  and,  thirdly  and 
lastly,  of  a  small  quantity  of  secreting  structure,  consisting  of  nuclei 
only,  and  which  appears  to  lie  in  the  intervals  between  the  blood- 
vessels.*    (See  Plate  LXII.  fig.  2.) 

The  above  comprehends  all  that  can  be  readily  made  out  of  structure 
in  the  spleen :  the  examination,  however,  of  this  organ  is  by  no  means 
satisfactory  or  easy  on  account  of  the  impossibility  of  fully  injecting 
it,  a  difficulty  which  arises  from  causes  but  imperfectly  understood. 

Dr.  Julian  Evans,  however,  describes  a  very  elaborate  structure 
and  arrangement  of  the  tissues  in  the  spleen,  as  will  be  seen  from  the 
perusal  of  the  following  abstract  of  his  paper,  taken  from  the  third 
edition  of  Carpenter's  "Principles  of  Human  Physiology:" 

"  According  to  the  account  of  Dr.  Julian  Evans.f  whose  researches 
appear  to  have  been  more  successful  than  those  of  any  other  anato- 
mist, the  spleen  essentially  consists  of  a  fibrous  membrane,  which 
constitutes  its  exterior  envelope,  and  which  sends  prolongations  in  all 
directions  across  its  interior,  so  as  to  divide  it  into  a  number  of  minute 
cavities  or  lacunas  of  irregular  form.  These  splenic  lacuna  com- 
municate freely  with  each  other,  and  with  the  splenic  vein ;  and  they 
are  lined  by  a  continuation  of  the  lining  membrane  of  the  latter, 

*See  Med.  Chir.  Rev.  No.  X.  p.  28.  \  Lancet,  April  6th,  1844. 


490  THE     SOLIDS. 

which  is  so  reflected  upon  itself  as  to  leave  oval  or  circular  foramina 
by  which  each  lacuna  opens  into  others,  or  into  the  splenic  vein. 
The  lacunae,  whos'e  usual  diameter  is  estimated  by  Dr.  E.  at  from  halt 
to  one-third  of  a  line,  are  generally  traversed  by  filaments  of  elastic 
tissue,  imbedded  in  which  a  small  artery  and  vein  may  be  frequently 
observed;  over  these  filaments,  the  lining  membrane  is  reflected  in 
folds;  and,  in  this  manner,  each  lacuna  is  incompletely  divided  into 
two  or  more  smaller  compartments.  There  is  no  direct  communi- 
cation between  the  splenic  artery  and  the  interior  of  the  lacunas ;  but 
its  branches  are  distributed  through  the  inter-cellular  parenchyma 
(which  will  be  presently  described) ;  and  the  small  veins  which  collect 
the  blood  from  the  capillaries  of  the  organ  convey  it  into  these  cavities, 
from  which  it  is  conveyed  away  by  the  splenic  vein.  The  lacunae 
may  be  readily  injected  from  the  splenic  vein  with  either  air  or  liquid, 
provided  they  are  not  filled  with  coagulated  blood ;  and  they  are  so 
distensible,  that  the  organ  may  be  made  to  dilate  to  many  times  its 
original  size  with  very  little  force.  This  is  especially  the  case  in  the 
spleen  of  the  Herbivora;  for  the  spleen  of  a  sheep  weighing  four 
ounces,  may  be  easily  made  to  contain  thirty  ounces  of  water. 
That  of  man,  however,  is  less  capable  of  this  kind  of  enlargement. 
According  to  Dr.  Evans,  the  lacunae  of  the  spleen  never  contain  any 
thing  but  blood :  and  he  notices  that  a  frequent  condition  of  the  human 
spleen  after  death,  which  is  sometimes  described  as  a  morbid  appear- 
ance, consists  in  the  filling  of  the  lacunae  with  firmly  coagulated  blood, 
which  gives  a  granular  appearance  to  the  organ. 

"The  partitions  between  the  lacunae  are  formed,  not  only  by  the 
membranes  already  mentioned,  but  by  the  peculiar  parenchyma  of  the 
spleen ;  which  constitutes  a  larger  part  of  the  organ  in  man,  than  in 
the  Herbivorous  Mammalia.  It  presents  a  half-fluid  appearance  to  the 
eye ;  but  when  an  attempt  is  made  to  tear  it,  considerable  resistance 
is  experienced,  in  consequence  of  its  being  intersected  by  what  appear 
to  be  minute  fibres.  When  a  small  portion  of  it  is  pressed,  a  liquid  is 
separated:  which  is  that  commonly  known  as  the  Liquor  Lienis,  or 
splenic  blood;  which  is  usually  described  (but  erroneously,  according 
to  Dr.  E.)  as  filling  the  lacunae  of  the  spleen.  This  liquid,  when  diluted 
with  serum,  and  examined  under  the  microscope,  is  found  to  contain 
two  kinds  of  corpuscles — one  sort  being  apparently  identical  with 
ordinary  blood  corpuscles,  and  the  other  with  the  globules  character- 
istic of  the  lymph,  and  abundant  in  the  lymphatic  glands.  The 
remaining  fibrous  substance  consists  entirely  of  capillary  blood-vessels 


GLANDS.  491 

and  lymphatics,  with  minute  corpuscles,  much  smaller  than  blood 
corpuscles,  varying  in  size  from  about  1 -6000th  to  1 -7000th  of  an 
inch,  of  spherical  form,  and  usually  corrugated  on  the  surface.  These 
lie  in  great  numbers  in  the  meshes  of  the  sanguiferous  capillaries; 
and  the  minute  lymphatics  are  described  by  Dr.  E.  as  connected  with 
the  splenic  corpuscles,  and  apparently  arising  from  them.  Lying  in 
the  midst  of  the  parenchyma,  are  found  a  large  number  of  bodies,  of 
about  a  third  of  a  line  in  diameter,  which  are  evidently  in  close  con- 
nexion with  the  vascular  system;  these  have  been  long  known  as  the 
Malpighian  bodies  of  the  spleen,  after  the  name  of  their  discoverer ; 
but  since  his  time,  their  existence  has  been  denied,  or  other  appear- 
ances have  been  mistaken  for  them. 

"According  to  Dr.  E.,  they  in  all  respects  resemble  the  mesenteric, 
or  lymphatic  glands  in  miniature,  consisting  as  they  do  of  convoluted 
masses  of  blood-vessels  and  lymphatics,  united  together  by  elastic 
tissue,  so  as  to  possess  considerable  firmness:  and  they  further  cor- 
respond with  them  in  this — that  the  lymph  they  contain,  which  was 
quite  transparent  in  their  afferent  lymphatics,  now  becomes  somewhat 
milky,  from  containing  a  large  number  of  lymph  globules." 

Dr.  Handfield  Jones  has  noticed  the  occurrence  of  certain  peculiar 
corpuscles  in  the  spleen  of  various  animals,  including  that  of  fishes, 
mammals,  and  man;  these  corpuscles  he  describes  as  follows:* 

"In  the  spleens  of  various  animals  there  may  often  be  seen  a  number 
of  minute  corpuscles  of  a  yellow  colour,  varying  from  a  dark  to  a  pale 
hue;  they  occur  sometimes  singly,  but  mostly  in  groups,  which  I  have 
sometimes  thought  were  aggregated,  especially  along  the  larger  blood 
canals.  These  groups  are  made  up  of  corpuscles  of  very  various 
size;  they  do  not  appear  to  have  any  special  connexion  with  the 
surrounding  substance,  which  occasionally,  however,  has  a  decided 
yellow  tinge.  ■ 

"In  the  animal  series,  I  have  found  these  corpuscles  most  highly 
developed  in  fishes.  In  the  human  subject,  they  are  rarely  to  be 
found.  I  have,  however,  observed  them  distinctly  in  six  instances,  in 
one  of  which  they  were  very  large  and  numerous.  In  most  of  the 
cases  in  which  they  were  found,  there  had  been  considerable  inter- 
ruption to  the  respiratory  process.  The  spleen  was  generally  much 
enlarged,  soft,  and  of  rather  a  pale  colour,  quite  an  opposite  condition 
to  that  often  observed  in  cases  of  'Bright's  Disease,'  where  the  organ 

*  Medical  Gazette,  1847,  p.  141. 


492  THE     SOLIDS. 

is  found  small  and  contracted:  in  such  spleens  I  have  never  found 
any  of  the  yellow  corpuscles." 

For  a  description  to  the  Pineal  and  Pituitary  glands,  placed  in  the 
classification  under  the  heading  "Vascular  Glands,"  the  reader  is 
referred  to  the  Appendix. 

ABSORBENT    GLANDS. 

The  absorbent  system  of  vessels  is  divisible  into  lacteals  and  lym- 
phatics, the  glands  attached  to  the  former  being  called  mesenteric, 
and  those  to  the  latter,  lymphatic  glands. 

The  lacteal  absorbents  commence  in  a  plexiform  manner  in  the 
villi  of  the  small  intestines,  while  the  lymphatic  absorbents  originate 
all  over  the  body,  in  the  same  manner,  in  each  of  the  several  tissues 
and  organs  of  which  it  is  composed :  they  are  minute,  delicate,  and 
transparent  vessels,  remarkable  for  their  uniformity  of  size,  a  knotted 
appearance  due  to  the  presence  of  numerous  valves,  the  dichotomous 
divisions  which  occur  in  their  course,  and  their  separation  into  several 
branches  immediately  before  entering  a  gland.* 

In  the  mesentery,  the  lacteals  become  variously  coiled  and  knotted, 
these  aggregations  of  coils,  together  with  fibrous  tissue  and  blood- 
vessels, forming  the  mesenteric  glands;  the  lymphatic  glands  have  a 
similar  structure  and  origin,  being  placed  in  certain  determinate 
regions  of  the  human  body. 

The  lymphatics 'which  enter  a  gland,  or  the  afferent  lymphatics, 
vary  in  number  from  two  to  six ;  they  divide  at  a  short  distance  from 
the  gland  into  several  smaller  vessels,  and  enter  it  by  one  of  the  flat- 
tened surfaces:  while  those  which  leave  it,  or  the  efferent  lymphatics, 
escape  from  the  gland  on  the  opposite,  but  not  unfrequently  on  the 
same  surface;  they  also  consist,  at  their  junction  with  the  gland,  of 
several  small  vessels,  which  unite  after  a  course  of  a  few  lines,  and 
form  from  one  to  three  trunks,  often  twice  as  large  as  the  afferent 
lymphatics. 

The  afferent  lacteals  and  lymphatics,  as  they  enter  the  gland, 
become  somewhat  dilated;  and  the  epithelium,  in  place  of  forming  a 
single  layer  of  flattened  cells  firmly  adherent  to  the  walls  of  the  tubes, 
consists  of  several  layers  of  rounded  and  glandular  cells,  which  are 
very  readily  displaced. 

These  cells  are  doubtless  more  or  less  concerned  in  the  elaboration 

fSee  the  Article  "Lymphatic  System,"  by  Mr.  Lane,  in  the  Cyclopaedia  of  Anatomy 
and  Physiology. 


GLANDS.  493 

of  the  fibrin  of  the  chyle ;  and  there  is  much  reason  to  believe  that 
from  time  to  time  the  more  mature  cells  become  detached  from  the  walls 
of  the  lacteals,  and  are  conveyed  along  with  the  chyle  into  the  blood, 
where  they  become  the  white  or  granular  corpuscles  of  that  fluid. 

Such  is  a  very  brief  outline  of  the  minute  anatomy  of  the  mesen- 
teric and  lymphatic  glands. 

This  is  probably  the  most  fit  place  to  introduce  a  few  remarks  on 
the  structure  of  the  villi  themselves,  the  chief  agents  in  the  absorp- 
tion of  the  chyme,  and  the  parts  in  which  the  lacteals  themselves 
take  their  origin. 

The  Villi  of  the  Intestines. 

The  villi  exist  in  the  whole  extent  of  the  small  intestines,  but  it  is  in 
the  lower  part  of  the  duodenum  and  the  whole  of  the  jejunum  that 
they  are  best  developed,  and  the  lacteals  most  readily  detected. 

Several  distinct  structures  have  to  be  noticed  and  described  enter- 
ing into  the  constitution  of  each  villus:  these  are  the  epithelium 
resting  upon  the  outer  surface  of  the  villus,  the  basement  membrane, 
the  intra- villous  nuclear  contents,  the  fatty  intra-villous  contents,  the 
blood-vessels  of  the  villus  and  its  lacteals ;  these  several  parts  will  be 
described  in  the  order  of  their  enumeration. 

The  epithelium  investing  the  villi  (see  Plate  LII.  fig.  1),  is  of  the 
conoidal  variety,  already  fully  described  and  figured.  It  not  merely 
clothes  the  villi  from  base  to  summit;  but  also  the  inter-spaces 
between  them,  as  well  as  the  numerous  follicles  of  Lieberkiihn,  situated 
in  the  whole  length  of  the  small  intestines. 

According  to  the  observations  of  Professor  Goodsir,  this  epithelium 
is  shed  on  each  recurrence  of  the  process  of  chymefication,  the  cells 
first  absorbing  the  partially  elaborated  chyme,  effecting  a  further 
elaboration  of  it,  and  finally  becoming  ruptured  and  dissolved,  set  free 
the  fluid  absorbed,  at  the  same  time  adding  their  own  substance  to 
augment  its  amount  and  nutritive  qualities. 

The  accuracy  of  this  view  is  in  the  main  admitted  by  most  observ- 
ers; Professor  Weber  and  Dr.  Jones,  however,  do  not  consider  that 
the  shedding  of  the  epithelium  is  necessary  to  enable  the  villi  to  per- 
form their  function';  and  the  latter  observer  makes  the  following 
remarks  on  this  point :  "  I  have  certainly  seen  the  villi  clad  with  their 
epithelium  when  the  lacteals  have  seemed  to  be  every  where  filled 
with  chyle :  however,  I  think  there  can  be  little  doubt  that,  when  the 
absorbing  process  is  most  actively  performed,  the  villus  does  throw 


494  THE     SOLIDS. 

off  its  protecting  covering;  certainly,  this  is  the  case  in  a  great 
number  of  instances."* 

The  basement  membrane  of  the  villi  is  a  continuation  of  that  of 
the  general  surface  of  the  mucous  membrane,  and  is,  as  far  as  has 
yet  been  ascertained,  perfectly  structureless. 

The  granular,  or,  more  correctly  speaking,  the  nuclear  contents  of 
the  villi  have  been  noticed  by  several  observers.  (See  Plate  LI  I.  Jigs. 
1,  2).  Dr.  Jones,  however,  in  the  communication  already  referred 
to,  has  pointed  out  the  fact  that  the  nuclear  and  granular  contents  of 
one  villus  are  continuous  with  those  of  another,  and  that  the  granules 
and  nuclei  form  a  continuous  stratum  lying  beneath  the  basement 
membrane,  extending  not  merely  from  villus  to  villus,  but  also 
throughout  the  large  intestines,  where  it  is  very  easily  seen  in  the 
spaces  between  the  follicles. 

Professor  Goodsir  has  described  these  granular  nuclei,  as  enlarging 
during  the  process  of  absorption,  and  as  forming  a  number  of  enlarged 
and  very  evident  cells  at  the  apex  of  the  villus.  These  supposed 
cells,  however,  are  nothing  more  than  oil  drops,  usually  of  a  brown 
colour,  and  of  various  sizes.  (See  Plate  LII.  jig.  2.)  At  this  con- 
clusion I  arrived  many  months  since,  and  gave  a  figure  of  these  oil 
drops  in  the  villi  in  the  13th  Part  of  the  Microscopic  Anatomy,  pub- 
lished in  April,  1848;  and  I  am  glad  that  Dr.  Jones  entertains  a 
similar  opinion  of  their  nature.  I  may  at  the  same  time  remark,  that 
the  cells  delineated  in  the  original  ^figure  given  by  Professor  Goodsir, 
have  all  the  characters  of  oil  drops,  being  round,  smooth,  and  reflect- 
ing the  light  strongly. 

The  use  of  these  oil  drops  in  the  villi  is  by  no  means  evident;  they 
are  formed,  in  all  probability,  by  the  cohesion  of  the  smaller  oily 
granules  which  are  scattered  throughout  the  villi  during  the  process 
of  absorption,  and  which  contribute  so  greatly  to  their  opacity;  in 
the  end,  they  are  most  probably  absorbed  by  the  lacteals. 

Notwithstanding,  however,  the  non-existence  of  the  peculiar  cells 
described  by  Professor  Goodsir,  the  leading  idea  of  that  observer  of 
the  elaboration  of  the  chyme  within  the  villus  is  still  correct,  the 
agents  in  this  work  being  the  nuclei  already  described. 

The  presence  of  these  nuclei  throughout  the  whole  length  of  the 
villus  seems  to  point  to  the  inference  that  it  is  not  the  apex  only 
which  absorbs. 

Each  villus  is  copiously  supplied  with  blood-vessels;  an  artery 

*  Medical  Gazette,  Nov.  17th,  1848. 


GLANDS.  495 

ascends  one  side  of  the  villus,  a  vein  descends  along  the  opposite  side, 
and  between  these  two  principal  vessels  a  very  complicated  and  beau- 
tiful plexus  of  capillaries  is  extended.     (See  Plate  LI.  figs.  3,  4,  5.) 

The  lacteals  are  described  as  originating  in  the  villi  in  a  plexiform 
manner. 

In  the  rabbit  I  have  observed  a  very  curious  construction  of  the 
villi,  their  surfaces  being  studded  with  numerous  mucous  follicles; 
the  portion  of  intestine  exhibiting  these  characters  was  most  probably 
taken  from  near  the  junction  of  the  large  and  small  intestines;  and  1 
have  little  doubt  but  that  the  villi  of  the  human  intestine,  in  a  corres- 
ponding position,  would  exhibit  the  same  combination  of  the  struct- 
ural peculiarities  of  both  small  and  large  intestines. 

The  anatomical  characters  of  the  mucous  membrane  of  the  stom- 
ach, and  large  intestines,  have  already  been  described.  (See  page 
339.  et  seq.) 


496  THE     SOLIDS, 


VILLI   OP   INTESTINES: 


[The  villi  of  the  intestines  can  only  be  examined  satisfactorily  after  injection, 
and  the  removal  of  the  epithelium.  They  may  be  seen,  but  not  so  well,  in 
the  recent  intestine,  after  the  epithelium  and  mucus  have  been  well  washed 
off,  on  examination  under  water  with  a  low  power.  In  the  fowl  and  dog,  as 
in  many  other  animals,  the  villi  are  longer  than  in  the  human  subject.  The 
intestines  may  be  injected  with  the  other  chylopoietic  viscera  from  the  vena 
portee,  or  they  may  be  injected  alone  from  the  superior  and  inferior  mesen- 
teric vein,  or  any  portion  of  the  intestinal  canal  may  be  isolated  by  applying 
ligatures  above  and  below  the  portion  to  be  injected,  containing  the  intestine 
and  mesentery,  and  the  pipe  of  the  syringe  then  placed  in  the  largest  mesen- 
teric  vein  discoverable  in  the  isolated  portion. 

After  the  injection  has  set,  the  intestine  must  be  placed  in  water,  to  allow 
the  epithelium  to  become  detached,  and  the  mucus  removed.  It  will  be 
sometimes  necessary  to  wash  the  internal  coat  of  the  intestine  with  water 
from  a  syringe.  These  injections  are  best  preserved  in  cells  and  in  fluid. 
Sometimes  it  will  be  found  desirable  to  preserve  longer  portions  of  intestine 
than  can  be  contained  in  cells  of  the  usual  size ;  for  this  purpose,  the  built- 
up  cells  already  described  will  be  of  service,  as  they  can  be  made  of  almost 
any  size. 

When  the  villi  are  long  and  well  filled,  the  vessels  are  sometimes  beauti- 
fully shown  in  transverse  sections,  mounted  in  balsam  without  heat. 

Plate  LXXIV.,  fig.  5,  Villi  of  duodenum. 

"         "  fig.  6,  Villi  of  jejunum. 

Plate  LXXV.,  fig.  1,  Villi  of  ileum. 

"         "  fig.  2,  Muscular  fibre  of  small  intestine.] 


ORGANS  OF  THE  SENSES.  197 


ART.    XXII.— ORGANS    OF    THE    SENSES. 


Papillary  Structure  of  the  Skin. 

The  sense  of  Touch  is  the  simplest  as  well  as  the  most  universally- 
diffused  of  the  senses,  it  not  merely  extending  over  every  portion  of 
the  external  surface  of  the  body,  but  also  over  certain  of  the  internal 
mucous  surfaces,  as  those  of  part  of  the  mouth,  nose,  &c. 

Over  the  general  surface  of  the  body  this  sense  exists  under  the 
form  of  common  sensation;  and  it  is  only  in  certain  parts,  as  on  the 
palmar  and  plantar  surfaces  of  the  hands  and  feet,  that  it  becomes  so 
highly  developed  as  to  assume  the  importance  of  a  distinct  sense,  and 
to  deserve  the  name  of  Touch. 

This  sense  has  its  seat  in  the  papillary  structure  of  the  skin,  and 
the  degree  of  the  development  of  this  structure,  as  shown  by  the  size 
and  number  of  the  papillae,  is  always  proportionate  to  the  degree  of 
perfection  of  the  sense :  thus,  the  papillae  over  the  general  surface  of 
the  body  are  much  less  numerous  and  less  perfect  in  form  than  they 
are  in  the  palms  of  the  hands  and  soles  of  the  feet. 

The  papillae  in  the  natural  state  are  of  course  invested  by  the 
epidermis,  which  indeed  conceals  them  to  a  great  extent  from  view; 
this  requires  to  be  removed  by  maceration  before  their  form,  size,  and 
arrangement  can  be  clearly  ascertained. 

After  the  removal  of  the  epidermis,  it  will  be  seen  that  the  papillae 
on  the  general  surfaces  of  the  body  do  not  follow  any  definite  arrange- 
ment, but  are  scattered  here  and  there  without  apparent  order,  more 
or  less  thickly  according  to  the  degree  in  which  the  part  of  the  integu- 
ment upon  which  they  are  seated  is  endowed  with  sensation,  but 
every  where  they  are  less  numerous  than  on  the  palmar  and  plantar 
surfaces  of  the  hands  and  feet.     (See  Plate  LXIII.jftg-.  4.) 

On  the  palms  of  the  hands  and  soles  of  the  feet,  the  papillae  are 
arranged,  as  may  be  seen  with  the  naked  eye,  in  lines  or  ridges,  each  • 
ridge  being  made  up  of  two  rows  of  papillae  in  single  file,  and  between 
each  pair  of  which  a  further  line  of  separation  may  be  traced  :  such 
is  the  general  disposition  of  the  papillae  in  each  ridge ;  the  ducts  of 
the  sudoriferous  glands  pass  through  its  centre  and  between  the  rows 
of  papillae,  the  number  of  these  glands  and  ducts  to  that  of  the  papillae 
being  in  the  proportion  of  one  to  four.     (See  Plate  LX.lIl.fig.  3.) 

32 


498  THE     SOLIDS. 

The  arrangement  just  described  can  be  well  seen  on  the  palms  of 
the  hands  by  the  aid  of  a  lens,  even  while  the  epidermis  is  still 
attached  to  the  cutis ;  the  ridges  are  seen  to  be  disposed  here  and 
there  in  beautiful  curves,  some  abruptly  coming  to  a  termination,  and 
others  dividing  into  two  distinct  ridges,  this  disposition  enabling  them 
to  adapt  themselves  more  accurately  to  the  varying  nature  of  the 
surface  over  which  they  are  extended :  along  the  middle  of  each  ridge, 
the  apertures  of  the  numerous  sudoriferous  glands  may  be  seen  for 
the  most  part  crossed  in  the  direction  of  the  diameter  of  the  ridge  by 
a  faint  groove,  which  indicates  the  line  of  separation  of  the  papillae 
into  pairs.     (See  Plate  hXlll.Jig.  1.) 

Each  papilla  appears  to  consist  of  a  prolongation  of  basement 
membrane,  and  contains  in  its  interior  granular  and  nuclear  contents 
and  a  single  looped  blood-vessel,  (see  Plate  LXIII.  Jigs.  3.  7) :  these 
points  of  structure  are  all  made  out  readily  enough;  the  chief  difficulty 
consists  in  the  determination  of  the  manner  in  which  the  nerve  fila- 
ments, with  which  the  papillae  are  undoubtedly  supplied,  terminate  in 
them.  On  this  subject,  Messrs.  Todd  and  Bowman*  have  the  follow- 
ing observations: — "In  regard  to  the  presence  of  nerves  in  the  papillae 
themselves,  we  can  affirm  that  we  have,  distinctly  traced  solitary 
tubules  ascending  among  the  other  tissues  of  the  papillae  about  half 
way  to  their  summits,  but  then  becoming  lost  to  sight,  either  by  simply 
ending,  or  else  by  losing  the  white  substance  of  Schwann,  which  alone 
enables  us  to  distinguish  them  in  such  situations  from  other  textures. 
Thin  vertical  sections  of  perfectly  fresh  specimens  are  essential  for  this 
investigation,  and  the  observer  should  try  upon  them  the  several  effects 
of  acetic  acid  and  solution  of  potass.  In  thus  describing  the  nerves-of 
the  papillae  from  our  own  observations,  we  do  not  deny  the  existence 
of  true  loop-like  terminations  as  figured  by  so  respectable  an  authority 
as  Gerber ;  but  neither  do  we  feel  entitled  to  assent  to  it.  .  .  .  We 
incline  to  the  belief  that  the  tubules,  either  entirely  or  in  a  great 
measure,  lose  the  white  substance  when  within  the  papillae." 

Messrs.  Todd  and  Bowman  further  observe,  in  reference  to  the 
structure  of  the  papillae : — "  Within  the  basement  membrane  it  is 
difficult  to  distinguish  any  special  tissue,  except  by  artificial  modes  of 
preparation.  A  fibrous  structure,  however,  is  apparent,  having  a 
more  or  less  vertical  arrangement ;  and  with  the  help  of  solution  of 
potass,  filaments  of  extreme  delicacy,  which  seeem  to  be  of  the  elastic 
kind,  are  generally  discoverable  in  it." 

*  Physiological  Anatomy,  p.  412. 


ORGANS  OF  THE  SENSES.  499 

The  blood-vessels  of  the  papillae  consist  of  single  loops;  each  of 
these  is  made  up  of  an  artery  and  a  vein:  the  former,  derived  from 
the  arterial  plexus  of  the  cutis,  ascends  the  papilla  on  one  side,  and 
on  reaching  its  summit  gradually  merges  into  the  vein  which  descends 
along  its  opposite  side,  and  terminates  in  the  venous  plexus  of  the 
cutis.  In  an  injected  preparation,  and  where  the  villi  are  large,  the 
turn  of  the  loop  is  seen  to  be  very  abrupt,  the  two  vessels,  the  artery 
and  the  vein,  coiling  round  each  other,  and  resembling  a  piece  of 
twine  which  has  been  bent  upon  itself  and  afterwards  twisted  in  a 
spiral  manner.  This  disposition  of  the  vessels  seems  intended  to 
delay  somewhat  the  passage  of  the  blood  through  the  papillae.  (See 
Plate  imil.jig.  7.) 

The  thickness  of  the  epidermis  which  so  closely  invests  the  papillae, 
does  not  appear  to  have  any  direct  relation  to  the  sense  of  touch  f 
thus,  over  the  general  surface  of  the  body,  where  this  sense  exists 
only  as  common  sensation,  the  epidermis  is  very  thin,  while  over  the 
palmar  surface  of  the  hands  it  is  very  thick;  the  epidermis  must  not 
be  too  thick,  however,  even  in  this  situation,  as  is  shown  by  the  fact, 
that  where  it  has  been  greatly  thickened  by  manual  labour,  touch  is 
totally  obscured. 

The  density  of  the  epidermis  in  certain  situations  is  evidently  due 
to  pressure,  and  may  be  explained  by  the  fact  that  such  pressure 
induces  an  increased  determination  of  blood  to  the  part,  which  is 
followed  by  increased  nutrition  and  development.  Between  the 
sense  of  touch  and  the  number  of  sudoriferous  glands,  there  would 
appear  to  be  a  certain  relation:  thus,  on  the  palmar  aspect  of  the 
hands,  where  this  sense  exists  in  its  highest  perfection,  the  number  of 
sweat  glands  is  very  great. 

The  use  of  these  glands  in  this  situation  in  such  increased  numbers, 
may  readily  be  conceived  to  be  to  keep  the  epidermis  in  a  moist  and 
flexible  condition,  whereby  impressions  would  be  more  readily  con- 
veyed to  the  papillae  and  more  distinctly  felt,  the  acuteness  of  the 
entire  sense  being  thus  greatly  augmented. 

The  epidermis  is  very  accurately  adapted  to  the  papillae,  so  that 
when  detached  and  viewed  upon  its  under  surface,  it  is  seen  to  con- 
tain exact  impressions  of  each  and  all  of  them;  it  is  in  this  manner 
that  their  form,  size,  number,  and  arrangement  are  best  studied,  and 
it  will  then  be  noticed  that,  in  all  these  particulars,  considerable 
variations  exist.     (See  Plate  LXIII.  Jigs.  5,  6.) 


500  THE     SOLIDS 


PAPILLA   OP   SKIN: 

[The  papillse  of  the  skin  may  be  examined  in  their  recent  state  on 
detaching  the  epidermis  after  slight  maceration :  the  papillse  may  then  be 
viewed  in  thin  transverse  sections  of  the  skin,  as  directed  in  the  prepara- 
tion of  the  sudoriparous  glands.  The  loopings  of  the  vessels  investing  the 
papillse,  can  only  be  seen  after  injection.  In  some  cases  of  very  success- 
ful minute  injection  of  the  whole  body,  the  capillaries  of  the  skin  will  be 
found  filled;  but  this  success  is  rare,  except  in  foetal  subjects.  Injections 
of  the  skin  may  sometimes  be  made  of  one  extremity — as  one  arm,  or  a 
hand  or  foot.     In  these  attempts,  the  injection  must  be  made  by  the  vein. 

When  success  is  obtained,  those  portions  of  skin  that  show  best  the  papillae, 
and  these  will  be  found  on  the  palmar  surface  of  the  hand  and  fingers, 
may  be  preserved  in  cells  with  fluid.  Other  portions  should  be  allowed  to 
dry,  and  transverse  sections  made  and  mounted  in  balsam.] 


ORGANS  OF  THE  SENSES.  501 


Papillary  Structure  of  the  Mucous  Membrane  of  the  Tongue. 

The  mucous  membrane  of  the  tongue,  the  principal,  if  not  the  sole 
seat  of  the  sense  of  taste,  is  divisible,  like  the  skin,  into  a  chorium,  a 
papillary  structure,  and  an  epidermis  or  epithelium. 

The  chorium  is  a  firm  and  tough  membrane,  formed  of  mixed  fibrous 
tissue,  and  containing  in  its  substance  the  blood-vessels  and  nerves, 
arranged  in  a  plexiform  manner,  from  which  the  papillae  are  supplied : 
to  its  under  surface  the  extremities  of  the  mascular  fibres  of  the  mus- 
cles of  the  tongue  are  firmly  attached;  this  arrangement  imparts  to 
the  whole  organ  a  considerable  power  of  movement  and  of  nice 
adaptation. 

The  papillary  structure,  which  is  the  real  seat  of  the  sense  of  taste, 
is  constituted  of  an  immense  number  of  papillae,  which  occasion  a 
somewhat  flocculent  appearance  of  the  whole  surface  of  the  tongue. 

The  papillae  are  divisible  into  simple  and  compound,  and  the  latter 
again  into  filiform,  fungiform,  and  calyciform;  besides  these  several 
compound  forms,  however,  others  exist  of  no  very  definite  shape,  but 
approaching  more  or  less  closely  in  their  characters  to  either  the 
fungiform  or  calyciform  papillae. 

The  simple  papillae  exist  principally  on  the  sides  and  under  surface 
of  the  tongue,  but  also,  though  more  sparingly,  on  its  upper  surface, 
as  between  the  filiform  papilae,  in  the  space  around  the  base  of  each 
fungiform  papilla,  and  for  a  short  distance  behind  the  calyciform 
papillae,  and  to  either  side  of  them.     (See  Plate  LXY.fig.  10.) 

They  vary  somewhat  in  size,  form,  and  structure  in  difFerent  situa- 
tions ;  in  general  they  are  much  pointed  at  their  extremities :  behind 
the  calycform  papillae  they  are  obtuse  and  pyriform  in  shape,  (see 
Plate  LXV.  fig.  11,)  while  on  the  under  surface  of  the  tongue  their 
extremities  are  very  frequently  perforated,  and  they  appear  to  serve 
the  double  purpose  of  a  papilla  and  mucous  follicle.  (See  Plate  LXV. 
fig-  2.) 

They  each  consist  of,  in  addition  to  their  epithelial  investment,  a 
layer  of  basement  membrane,  a  single  looped  blood-vessel,  filaments 
of  nerves,  and  granular  and  nuclear  contents.  (See  Plate  LXV.  fig. 
6;  and  Plate  LXVI.^g-.  5.) 

The  compound  papillae  are  confined  to  the  upper  surface  and  edges 
of  the  tongue,  and  do  not  extend,  except  for  a  short  distance  at  the 


502  THE     SOLIDS. 

sides,  over  the  space  bounded  in  front  by  the  calyciform  papillae,  and 
behind  by  the  epiglottis.  This  chain  of  papillae  forms  the  extreme 
boundary  of  the  space  over  which  the  sense  of  taste  extends,  the  surface 
behind  it  being  smooth,  non-papillary,  and  exhibiting  numerous  open- 
ings of  mucous  glands;  thus  then  it  would  appear  we  have  a  true 
gustatory  region. 

Each  compound  papilla  is  made  up  of  numerous  simple  papillae, 
arranged  differently  in  the  case  of  the  three  forms  of  these  already 
enumerated. 

The  filiform  papillae  are  by  far  the  most  numerous,  being  more 
than  in  the  proportion  of  twenty  to  one ;  when  freed  from  epithelium 
they  are  seen  to  be  more  or  less  cylindrical  in  form,  and  to  consist 
of  a  variable  number  of  simple  papillae,  from  sixteen  to  twenty  or 
more  to  each,  arranged  in  a  single  circular  series,  forming  the  top  and 
margin  of  the  cylinder.  (See  Plate  LXIV.  fig.  3.)  The  sides  of  the 
simple  papillae  are  more  or  less  united  together,  but  the  tips  are  free 
and  pointed,  some  more  so  than  others. 

The  length  of  the  cylinder  which  each  filiform  papilla  describes,  the 
degree  of  acumination  of  the  apices  of  the  secondary  papillae,  and  the 
extent  of  these  which  is  free,  vary  in  accordance  with  the  position  of 
the  papillae  on  the  tongue. 

The  circular  disposition  referred  to  is  best  seen  in  the  papillae  placed 
near  the  tip  and  sides  of  the  tongue,  for  in  those  situations  the  sec- 
ondary papillae  are  short,  blunt,  and  nearly  of  equal  lengths.  (See 
Plate  LXIV.  fig.  3.)  In  the  centre  of  the  organ  the  simple  or  second- 
ary papillae  are  much  longer,  and  more  slender,  so  that  they  fall 
together  and  variously  intermix  with  each  other,  and  thus  it  is  that 
the  circular  disposition  in  them  is  usually  more  or  less  concealed  from 
view.     (See  Plate  LXIV.  fig.  4.) 

This  disposition  of  the  secondary  papillae  includes  of  course,  as  a 
consequence,  a  corresponding  arrangement  of  the  blood-vessels,  (a 
single  looped  vessel  proceeding  to  each,)  and  of  the  nerve  filaments, 
which  are  in  like  manner  arranged  in  circles.     (See  Plate  LXVI. 

fig-  4.) 

The  centre  of  each  filiform  papilla  is  hollowed  out,  and  is  to  be 
regarded  as  a  large  mucous  follicle,  and  thus  the  comparison  of  these 
papillae  to  a  cylinder  is  rendered  almost  complete.     (See  Plate  LXIV. 

fig-  3.) 

We  shall  presently  see  that  the  same  circular  arrangement  extends 


ORGANS  OF  THE  SENSES.  503 

to  the  filiform  epithelial  appendages  hereafter  to  be  described,  and  one 
of  which  corresponds  to  each  secondary  papilla.* 

The  fungiform  papillae  are  seated  principally  on  the  tip  and  sides 
of  the  tongue,  at  least  they  are  most  evident  in  those  situations,  and 
around  each  a  space  or  shallow  fossa,  dotted  with  numerous  simple 
papillae,  may  be  observed ;  they  are  distinguished  from  the  filiform 
papillae  by  which  they  are  surrounded,  by  their  form,  being  narrow 
at  the  base,  and  dilated  near  the  summit,  by  being  clothed  all  over 
with  simple  papillae,  which  are  usually  a  good  deal  compressed  in 
form,  and  by  the  tenuity  of  the  epithelium,  destitute  of  filiform  append- 
ages, which  covers  them,  and  which  allows  of  the  blood  in  the  vessels 
being  seen  through  it.     (See  Plate  LXIV.  jig.  5.) 

At  the  edges  of  the  tongue,  and  at  the  sides  behind  the  calyciform 
papillae,  compound  papillae  exist,  which  bear  some  resemblance  to  the 
fungiform  papillae,  of  which  they  may  be  described  as  modifications; 
they  differ  from  ordinary  fungiform  papillae,  however,  in  being  sessile 
and  simply  rounded;  in  the  form  of  the  simple  papillae  which  clothes 
them,  and  which  usually  are  not  compressed,  but  swollen  at  the 
extremity,  or  pyriform.     (See  Plate  LXV.  jig.  11.) 

The  calyciform  papillae  bound  the  true  gustatory  region  posteriorly ; 
they  are  seven  or  eight  in  number,  and  arranged  in  two  rows,  which 
meet  behind  in  the  foramen  caecum,  and  enclose  a  V-shaped  space, 
the  concavity  of  which  looks  forward. 

They  each  consist  of  a  depression  or  cup,  out  of  which  a  large 
papilla,  sometimes  more  or  less  adherent  to  the  rim  of  the  cup,  arises, 
and  the  level  of  which  it  but  little  exceeds ;  the  central  papilla,  as  well 
as  the  sides  and  margin  of  the  cup,  are  closely  set  with  very  many 
simple  papillae,  which  are  short,  obtuse,  and  dilated  at  their  extremities. 
A  calyciform  papilla,  perfectly  freed  from  epithelium,  and  with  all  the 
secondary  papillae  visible,  forms  a  very  beautiful  object.  (See  Plate 
hXVI.Jg.  1.) 

The  foramen  ccecum  usually  contains  one  and  sometimes  two  large 
papillae,  similarly  clothed  with  secondary  papillae,  and  according  as 
it  includes  one  or  two  papillae,  it  is  to  be  regarded  as  a  single  or 
double  modified  calyciform  papilla. 

In  front  of  the  calyciform  papillae,  in  some  tongues,  a  number  of 
large   and  irregular   papillae   exist,  invested  with  secondary  papillae 

*  The  form  and  structure  of  the  filiform  papilla,  as  above  detailed,  was  first 
described  by  me  in  the  Lancet  of  3d  March,  1849. 


404  THE     SOLIDS. 

similar  to  those  of  the  calyciform  papillae,  but  not,  like  the  latter,  seated 
in  cups. 

On  the  edges  and  under  surface  of  the  tongue  numerous  mucous 
follicles  are  observed :  it  is  sometimes,  however,  difficult  to  distinguish 
between  these  and  simple  papillae,  in  consequence  of  the  latter  being 
frequently  perforated  in  the  centre,  and  thus  combining  the  charac- 
ters of  both  follicles  and  papillae.     (See  Plate  LXV.figs.  1,  2,  3.) 

The  epithelial  investment  of  the  tongue  adheres  very  closely  to  the 
papillae,  and  generally  requires  one  or  two  weeks'  maceration  for  its 
complete  removal;  even  then,  in  but  few  instances  in  the  human  sub- 
ject, can  it  be  removed  in  entire  pieces,  it  in  most  cases  crumbling 
away  into  its  constituent  cells. 

It  adapts  itself  accurately  to  the  papillary  structure  of  the  tongue, 
and  is  of  sufficient  thickness  to  conceal  effectually  the  simple  papillae, 
whether  these  exist  by  themselves  or  constitute  by  their  aggregation 
the  compound  papillae.  For  the  satisfactory  study  of  the  papillae, 
therefore,  it  is  absolutely  necessary  that  the  epithelium  should  be 
entirely  removed. 

The  epithelium  of  the  tongue  presents  all  the  characters  of  the 
epidermis  of  the  skin,  consisting,  like  it,  of  numerous  layers  of  large 
and  nucleated  cells,  those  forming  the  outer  layers  being  flattened  and 
membranous,  while  the  deeper-seated  cells  are  rounded  and  granular. 
(See  Plate  LXY.fig.  6.) 

The  thickness  of  the  epithelium  of  the  tongue  in  the  human  subject 
varies  very  considerably  in  different  cases,  and  would  appear  to  be 
much  affected  by  disease;  it  in  some  cases  even  being  entirely  absent. 

It  is  thickest  over  the  simple  papillae,  which  are  usually  entirely 
concealed  by  it ;  over  the  fungiform  and  calyciform  papillae  it  is  very 
thin  and  delicate,  while  over  the  filiform  papillae  it  is  prolonged  into 
long  filiform  processes,  which  correspond  in  number  and  arrangement 
with  the  secondary  papillae  themselves.     (See  Plate  LIV.  fig.  1,  2.) 

These  filiform  appendages  vary  much  in  length,  being  very  short 
upon  the  sides  and  near  the  tip  of  the  tongue,  but  three  or  four  times 
as  long  near  its  centre  (see  Plate  LIV.  fig.  1,2);  at  the  very  tip  they 
are  often  entirely  wanting,  the  papillae  in  this  situation  presenting  the 
appearance  of  large  open  follicles  with  slightly  spinous  rims.  (See 
Plate  LV.  fig.  4.) 

Each  filiform  process  is  constituted  of  flattened  epithelial  scales, 
which  lie  in  the  direction  of  their  length,  and  frequently  contains  a 
canal  in  its  centre. 


ORGANS  OF  THE  SENSES.  505 

Tubular  nerve  filaments,  terminating  in  loops,  have  been  discovered 
in  the  fungiform  and  filiform  papillae,  but  not  hitherto  in  either  the 
simple  or  calyciform  papillae,  although  nerve  filaments,  in  some  form 
or  other,  doubtless  exist  in  these  also. 

The  internal  minute  structure  of  the  three  principal  forms  of  com- 
pound papillae  requires  a  careful  and  searching  examination,  with  a 
view  to  the  determination  of  their  respective  functions.  From  a  con- 
sideration of  their  outward  configuration,  they  would  all  appear  to  be 
w.^11  adapted  to  receive  gustatory  impressions.  The  fungiform  papillae 
set  m  to  be  so  by  their  prominence  and  the  delicacy  of  the  epithelium 
by  vhich  they  are  invested,  the  calyciform  papillae  also  by  the  tenuity 
of  tl  eir  epithelial  covering  and  by  their  cupped  form,  and  the  filiform 
papi^ae,  by  reason  of  the  cavity  which  occupies  the  centre  of  each, 
and  tiie  regular  disposition  of  the  secondary  papillae  around  this. 

An\  additional,  and  to  my  mind,  indeed,  an  almost  conclusive  reason 
in  fav bur  of  the  subserviency  of  the  filiform  papillae  to  the  reception  of 
gustatory  impressions,  is  derived  from  the  consideration  that  they 
cover  nineteen-twentieths  of  the  mucous  membrane  of  the  tongue", 
and  it  is  but  natural  to  suppose  that  the  principal  portion  of  this  is 
destined  to  the  discharge  of  the  function  for  which  it  has  so  evidently 
been  designed. 

The  filamentary  papillae  have  generally  been  considered  to  be  ill 
adapted  to  the  reception  of  gustatory  impressions,  in  consequence  of 
the  character  of  the  epithelial  processes  in  connexion  with  them ;  and 
it  has  been  supposed  that  they  are  to  be  regarded  as  tactile  rather 
than  gustatory  organs.  This  opinion  has,  however,  been  entertained 
in  the  absence  of  a  full  knowledge  of  the  real  form  and  structure  of 
these  papillae,  as  already  shown. 

It  has  occurred  to  me  that  these  filamentary  processes  act  as 
absorbents  of  the  nutrient  juices,  and  that  collectively  they  constitute 
an  absorbent  surface  of  considerable  power,  conveying  directly  to  the 
papilla  those  fluids,  and  keeping  them  in  contact  with  the  papillae  for 
a  time,  thus  prolonging  the  duration  of  the  gustatory  impression. 
This  idea  would  appear  to  gather  confirmation  from  the  fact  that  it  is 
in  these  filamentary  epithelial  prolongations  tljat  the  variable  coating 
known  as  the  fur  of  the  tongue  has  its  seat. 

SMELL. 

Structure  of  the  Mucous  Membrane  of  the  Nose. 
The  anatomical  characters  of  the  mucous  membrane  of  the  nose 


500  THE     SOLIDS. 

differ  in  different  regions;  for  a  short  distance  within  the  anterior 
nares,  the  mucous  membrane  presents  many  of  the  characters  of  the 
skin,  it  being  divisible  into  chorion,  papillary  structure,  and  epider- 
mis; the  papillae  resemble  in  every  respect  those  of  the  sense  ol 
touch,  and  the  epidermis  consists  of  flattened  epithelial  scales  analo- 
gous to  those  of  the  same  structure  in  the  skin.  This,  the  commence- 
ment of  the  nasal  mucous  membrane,  may  be  called  the  tactile 
region  of  the  nose,  and  it  is  abundantly  furnished  with  hairs,  which 
guard  the  entrances  of  the  nares,  and  the  roots  of  which  are  in  con- 
nexion with  the  ordinary  sebaceous  glands  of  the  hair  follicles. 

Higher  up  the  mucous  membrane  of  the  nose,  losing  its  papillae  and 
scaly  epithelium,  becomes  thick  and  soft,  and  presents  more  completely 
the  ordinary  appearances  of  a  mucous  membrane ;  imbedded  in  its 
substance  are  numerous  mucous  follicles  of  large  size,  having  but 
small  apertures,  which  are  best  seen  thickly  studding  the  surface  of 
the  membrane  after  slight  maceration  and  the  removal  of  the  epithe- 
lium. Between  and  around  these  the  blood-vessels  are  disposed,  the 
veins  being  particularly  large,  and  forming  a  very  evident  plexus,  each 
mesh  of  which  corresponds  with  a  follicle.    (See  Plate  LX1X.  fig.  2.) 

The  large  size  and  considerable  numbers  of  the  mucous  follicles 
explain  the  copious  secretion  which  proceeds  from  this  portion  of 
the  mucous  membrane,  when  suffering  from  irritation,  while  the 
venous  plexuses  sufficiently  account  for  the  disposition  of  this  part 
to  hemorrhage. 

This  is  by  far  the  largest  of  the  three  nasal  regions,  and  may  be 
denominated  the  jriluita?-y ;  the  epithelium  which  clothes  it  is  of  the 
ciliated  kind,  and  several  of  the  cavities  in  connexion  with  the 
meatuses  are  invested  by  a  similar  epithelium,  as  the  frontal  and 
sphenoidal  sinuses,  the  antrum  maxillare,  and  the  Eustachian  tubes. 
In  the  sinuses,  however,  the  mucous  membrane,  losing  its  follicles, 
becomes  much  reduced  in  thickness,  and  presents  the  characters  of  a 
fibrous  rather  than  of  a  mucous  structure. 

Still  higher  up  in  the  nose  we  come  upon  the  third  region,  which  has 
been  particularly  defined  and  described  by  the  authors  of  the  Physi- 
ological Anatomy  as  follows,  under  the  name  of  the  olfactory  region: 

"The  olfactory  region  is  situated  at  the  top  of  the  nose,  imme- 
diately below  the  cribriform  plate  of  the  ethmoid  bone,  through 
which  the  olfactory  nerves  reach  the  membrane;  and  it  extends  about 
one-third  or  one-fourth  downwards  on  the  septum,  and  over  the  supe- 
rior and  part  of  the  middle  spongy  bones  of  the  ethmoid.     Its  limits 


ORGANS  OF  THE  SENSES.  507 

are  distinctly  marked  by  a  more  or  less  rich  sienna-brown  tint  of  the 
epithelium,  and  by  a  remarkable  increase  in  the  thickness  of  this 
structure,  compared  with  the  ciliated  region  below ;  so  much  so,  that 
it  forms  an  opaque  soft  pulp  upon  the  surface  of  the  membrane,  very 
different  from  the  delicate,  very  transparent  film  of  the  sinuses  and 
lower  spongy  bones.  The  epithelium,  indeed,  here  quite  alters  its 
character,  being  no  longer  ciliated,  but  composed  of  an  aggregation  of 
superposed  nucleated  particles,  of  pretty  uniform  appearance  through- 
out ;  except  that  in  many  instances  a  layer  of  those  lying  deepest,  or 
almost  deepest,  is  of  a  darker  colour  than  the  rest,  from  the  brown 
pigment  contained  in  the  cells.  These  epithelial  particles,  then,  are 
not  ciliated;  and  they  form  a  thick,  soft,  and  pulpy  stratum,  resting 
on  the  basement  membrane.  The  deepest  layer  often  adheres  after 
the  others  are  washed  away.  On  looking  on  the  under  surface  of 
this  epithelium,  when  it  has  been  detached,  we  observe  projecting 
tubular  fragments  similar  to  the  cuticular  lining  drawn  out  of  the 
sweat-ducts  of  the  skin,  when  the  cuticle  is  removed  after  macera- 
tion. In  fact,  glands  apparently  identical  with  the  sweat-glands  exist 
in  this  region  in  great  numbers.  They  dip  down  in  the  recesses  of  the 
sub-mucous  tissue,  among  the  ramifications  of  the  olfactory  nerves; 
and  their  orifices  are  very  easily  seen,  after  the  general  brown  coat 
of  epithelium  has  been  detached,  lying  more  or  less  in  vertical  rows; 
the  arrangement  is  probably  determined  by  the  course  of  those  nerves 
beneath.  They  become  more  and  more  sparing  towards  the  limits  of 
the  olfactory  region.  The  epithelium  of  these  glands  is  bulky,  and, 
like  that  of  the  sweat-glands,  contains  some  pigment.  As  the  duct 
approaches  the  epithelium  of  the  general  surface,  its  wall  becomes 
thinner  and  more  transparent,  and  in  its  subsequent  course  upwards, 
it  is  difficult  to  be  traced,  for  it  does  not  appear  to  be  spiral,  or  its  par- 
ticles to  differ  from  those  which  they  traverse.  We  have  sometimes 
seen  rods  of  epithelium,  apparently  hollow,  left  projecting  from  the  base- 
ment membrane,  after  the  brown  epithelium  has  been  washed  away, 
and  these  are  perhaps  portions  of  the  excretory  ducts  of  these  glands." 
In  the  propriety  of  the  discrimination  of  this  region,  and  in  the 
accuracy  of  much  of  the  description  of  it  given  above,  the  author 
fully  concurs.  He  does  not,  however,  hesitate  to  affirm  that  no 
glands  at  all  analogous  to  sweat-glands  exist  in  it;  the  membrane  of 
this  region  is  indeed  thickly  studded  with  mucous  follicles,  apparently 
in  no  respect  dissimilar  to  those  of  the  pituitary  region,  except  that 
they  are  smaller  in  size,  and  more  delicate  in  structure. 


508  THE     SOLIDS. 

The  chief  characteristics  of  the  olfactory  region  consist,  then,  in 
its  glandular  epithelium,  in  the  presence  of  pigment  cells  lying  be- 
neath this,  in  its  more  delicate  structure,  in  the  presence  of  gelatinous 
nerve  filaments,  and  in  a  somewhat  different  arrangement  of  the 
blood-vessels.     (See  Plate  LXIX.  fig.  1.) 

In  the  sheep  this  region  is  rendered  almost  black  by  the  presence 
of  very  many  pigment  cells  which  are  of  the  stellate  form. 

Mr.  Quekett  pointed  out,  some  years  ago,  the  very  curious  fact  that 
the  blood-vessels  of  the  olfactory  region  of  the  human  foetus,  and  that 
of  mammalia  in  general,  are  disposed  in  loops,  the  convexity  of  each 
of  these  presenting  a  decided  dilatation.     (See  Plate  LXIX.  fig.  12.) 

Much  interest  is  attached  to  the  existence  of  these  loops,  since  they 
appear  to  indicate  the  presence  of  true  papillae  in  the  seat  of  smell  of 
the  mammalian  foetus ;  if  such  be  the  case,  however,  it  is  very  cer- 
tain that  neither  the  papillae  nor  loops  exist  in  the  olfactory  region  in 
the  adult  condition  of  the  nasal  organ. 

The  most  rigorous  search  has  failed  to  detect  the  presence  in  the 
olfactory  region  of  cells,  which  could  be  decidedly  pronounced  to  be 
nervous  or  ganglionic. 

The  nerves  of  the  nose  are  the  first  pair,  branches  of  the  fifth,  and 
motor  filaments  from  the  seventh  pair.  The  first  pair  are,  doubtless, 
the  proper  nerves  of  smell,  while  the  fifth  gives  common  sensibility  to 
the  nose. 

The  olfactory  lobes  are  prolongations  of  the  white  or  fibrous  por- 
tion of  the  brain,  and  consist,  like  it,  of  slender  tubular  nerve  fila- 
ments, intermixed  with  the  delicate  transparent  cells,  described  in  a 
previous  division  of  this  work. 

"  The  olfactory  filaments  are  from  fifteen  to  twenty-five  in  number, 
and  passing  through  the  apertures  of  the  cribriform  plate,  may  be 
seen  invested  with  fibrous  sheaths  derived  from  the  dura  mater,  upon 
the  deep  or  attached  surface  of  the  mucous  membrane  of  the  olfac- 
tory region.  They  here  branch,  and  sparingly  reunite  in  a  plexiform 
manner,  as  they  descend.  They  form  a  considerable  part  of  the 
entire  thickness  of  the  membrane,  and  differ  widely  from  the  ordinary 
cerebral  nerves  in  structure.  They  contain  no  white  substance  of 
Schwann,  are  not  divisible  into  elementary  fibrillae,  are  nucleated, 
and  finely  granular  in  texture ;  and  are  invested  with  a  sheath  of 
homogeneous  membrane,  much  resembling  the  sarcolemma,  or,  more 
strictly,  that  neurilemma  which  we  figured  from  the  nerves  of  insects 
in  a  former  volume.    These  facts  we  have  repeatedly  ascertained,  and 


ORGANS  OF  THE  SENSES.  509 

they  appear  to  be  of  great  importance  to  the  general  question  of  the 
function  of  the  several  ultimate  elements  of  the  nervous  structure, 
especially  when  viewed  in  connexion  with  what  will  be  said  on  the 
anatomy  of  the  retina.  We  are  aware  that  some  anatomists  deny  the 
existence  of  the  white  substance  of  Schwann  as  a  natural  element  of 
the  nerve  fibre  in  any  case,  pretending  that  it  is  formed  by  artificial 
modes  of  preparation.  We  hold  it  to  be  a  true  structure,  but  how- 
ever that  may  be,  these  nerves  never  exhibited  it,  however  prepared. 
They  rather  correspond  with  the  gelatinous  fibres.  Now,  there  is  no 
kind  of  doubt  that  they  are  a  direct  continuation  from  the  vesicular 
matter  of  the  olfactory  bulb.  The  arrangement  of  the  capillaries  in 
well-injected  specimens  is  a  convincing  proof  of  this,  as  these  vessels 
gradually  become  elongated  on  the  nerve  assuming  a  fibrous  charac- 
ter as  it  quits  the  surface  of  the  bulb ;  and,  further,  no  tubular  fibres 
can  ever  be  discovered  in  the  pulp  often  left  upon  the  orifices  of  the 
cribriform  plate  after  detachment  of  the  bulb.  It  must  be  remembered 
that  a  few  tubu  •  nbres  from  the  nasal  nerve  of  the  fifth  here  and* 
there  accompany  the  true  olfactory  filaments ;  but  these  only  serve 
to  make  the  difference  more  evident  by  contrast.'5 — Physiological 
Anatomy. 

VISION. 

Structure  of  the  Globe  of  the  Eye. 

The  structure  of  the  several  appendages  of  the  globe  of  the  eye  :  as  - 
the  eye-lids,  with  their  lashes,  and  Meibomian  glands,  the  caruncula 
lacrymalis,  the  lachrymal  gland,  muscles,  &c,  have  already  been  fully 
described  in  previous  sections  of  this  work ;  we  have  now  to  enter 
upon  the  description  of  the  numerous  parts  which  compose  the  essen- 
tial portion  of  the  organ  of  vision,  the  globe  of  the  eye  ;  each  of  these 
may  be  examined  in  much  the  same  order  in  which  they  would  natu- 
rally present  themselves  to  the  notice  of  an  ordinary  dissector,  and 
which  would  be  somewhat  as  follows :  Sclerotic  and  cornea ;  cho- 
roid, ciliary   processes,  and  iris  ;   retina ;   crystalline  lens ;  hyaloid 

membrane,  &c. 

Sclerotic. 

The  sclerotic  is  composed,  to  a  great  extent,  of  white  fibrous  tissue, 
intermixed  with  a  small  proportion  of  a  nucleated  form  of  elastic  tissue. 

These  tissues  are  disposed  in  a  laminated  manner,  the  fibres  of  one 
layer  crossing  those  of  another  more  or  less  at  right  angles ; — an 
arrangement  evidently  designed  to  render  this  the  protecting  tunic  of 
the  eye  more  firm  and  unyielding.     The  inner  surface  of  the  sclerotic 


510 


THE     SOLIDS. 


is  rough,  and  connected  with  the  choroid  by  the  lamina  fusca  of  that 
membrane,  to  be  described  hereafter. 

The  nutrition  of  the  sclerotic  is  provided  for  by  small  vessels  which 
ramify  on  its  outer  surface,  and  which  are  sparingly  continued  into 
its  substance. 

Anteriorly,  the  sclerotic  is  strengthened  by  the  tendinous  expan- 
sion of  the  four  recti  muscles,  known  as  the  tunica  albuginea,  or 
white  of  the  eye. 

Cornea. 

The  cornea,  although  in  a  state  of  health  as  clear  as  crystal,  yet 
possesses  a  complicated  and  beautiful  organization,  plainly  demon- 
strable with  the  aid  of  the  microscope. 

Notwithstanding  also  the  definite  line  of  demarcation  by  which  the 
limits  of  the  cornea  and  sclerotic  are  marked  out,  these  two  parts  are 
yet  inseparably  united  to  each  other ;  this  indissoluble  union  depend- 
ing upon  the  circumstance  of  the  existence  of  a  structural  connexion 
between  them,  the  nature  of  which  will  shortly  be  rendered  evident. 

The  cornea  is  clearly  divisible  into  four,  and,  according  to  some 
observers,  even  five  laminae.  These  are,  reckoning  from  before 
backwards,  conjunctival  epithelium,  cornea  proper,  posterior  elastic 
lamina,  and  the  epithelium  of  the  aqueous  humour ;  the  fifth  layer  has 
been  described  in  the  "  Physiological  Anatomy"  under  the  title  of 
the  "  anterior  elastic  lamina."  These  several  layers  will  be  separately 
noticed,  and  in  the  order  mentioned.     (See  Plate  LXVII.  fig.  1.) 

The  conjunctival  epithelium  forms  a  distinct  membrane  of  appre- 
ciable thickness,  and  capable  of  separation  as  such  shortly  after  death. 
It  consists  of  several  layers  of  super-imposed  cells,  which  partake  of 
many  of  the  characters  of  ordinary  epidermic  scales  or  cells. 

Those  cells  which  constitute  the  outer  or  more  superficial  layers 
are  large,  flat,  and  membranous ;  while  those  nearest  to  the  cornea 
proper,  and  which  appear  to  rest  directly  upon  it,  are  baton-shaped, 
and  disposed  vertically  to  the  surface  of  the  cornea.  (See  Plate 
LXVIII.  figs.  3.  5,  and  Plate  LXVII.  fig.  1.) 

After  death  this  epithelium  becomes  whitish  and  opaque,  and  it 
then  forms  the  film  of  the  eye. 

The  second  lamina,  according  to  the  observations  of  the  author,  is 
the  cornea  proper ;  and  it  is  this  which  constitutes  the  principal  bulk 
of  that  structure. 

Externally,  the  cornea  proper  is  firm  and  dense  in  texture,  but 
becomes  more  lax  and  soft  gradually  as  we  approach  the  interior;  it  is 


ORGANS  OF  THE  SENSES.  511 

this  external  and  firmer  portion  which  exhibits  the  lamellar  arrange- 
ment so  generally  described,  the  fibres  following  a  less  regular  course 
internally,  and  being  separated  by  wider  intervals. 

The  tissue  of  the  cornea  has  been  recently  described  as  a  peculiar 
modification  of  the  white  fibrous  element  of  the  sclerotic.  It  would 
appear,  however,  that  the  fibrous  tissue  of  which  it  is  constituted  is 
of  a  kind  totally  distinct  from  that  which  enters  so  largely  into  the 
composition  of  the  cornea  proper ;  a  conclusion  derived  from  its 
examination,  for  which  we  might  be  prepared,  simply  by  the  consider- 
ation of  the  very  opposite  physical  characters  of  the  two  parts,  the 
sclerotic  and  cornea,  the  former  being  white  and  opaque,  and  the 
latter  clear  and  diaphanous. 

If  we  tear  up  with  needles  a  small  portion  of  the  sclerotic,  and 
examine  it  with  the  microscope,  we  then  see  that  it  is  made  up,  for 
the  most  part,  of  bundles  of  wavy  and  distinct  fibres,  presenting 
scarcely  a  nucleus,  and  reflecting  a  yellowish  hue;  if  now  we  carry 
our  examination  still  further,  and  apply  acetic  acid  to  these  bundles, 
they  swell  up,  the  fibres  becoming  indistinct,  and  finally  converted 
into  a  jelly-like  substance. 

On  the  other  hand,  if  we  submit  a  portion  of  the  cornea  to  the  same 
examination,  and  the  same  treatment  by  acetic  acid,  we  shall  encoun- 
ter different  appearances  and  results.  In  the  first  place,  we  shall  not 
perceive  distinct  and  separate  bundles  of  fibrous  tissue  free  from 
nuclei,  but  we  shall  merely  notice  an  indistinct  fibrous  character  in 
the  mass,  with  here  and  there  elongated  nuclei  imperfectly  seen;  on 
the  application  of  acetic  acid,  however,  the  fibres  become  much  more 
evident,  and  multitudes  of  nuclei  are  brought  into  view.  Thus,  then, 
it  is  evident  that  the  tissue  of  the  cornea  is  something  more  than  a 
modification  of  the  white  fibrous  element  of  the  sclerotic.  The  nucle- 
ated fibres  just  described  are  often,  in  the  neighbourhood  of  the  nuclei 
themselves,  expanded  and  membraneous ;  and  it  is  remarkable  that  they 
do  not  lie  in  direct  apposition  with  each  other,  but  interlace  in  such  a 
manner  as  to  describe  elongated  spaces,  several  of  which  are  extended 
in  the  same  line.  These  spaces  are  oval  in  the  cornea,  and  round  in 
that  portion  of  the  sclerotic  where  the  two  structures  are  in  connexion 
with  each  other.*     (See  Plate  LX.YU.Jig.  3.) 

*  A  subsequent  examination  of  the  cornea  renders  it  necessary  that  the  views 
above  expressed  of  its  structure  should  be  modified  to  some  extent.  I  find  that  a 
considerable  amount  of  a  tissue,  wry  closely  resembling  the  white  fibrous  tissue  of 
the  sclerotic,  does  enter  into  the  construction  of  the  cornea ;  in  sections,  however, 


512  THE      SOLIDS. 

This  arrangement  was  first  pointed  out  by  the  authors  of  the 
"Physiological  Anatomy,"  and  is  thus  described  by  them.  "On  the 
cornea  proper  or  lamellated  cornea,  the  thickness  and  strength  of  the 
cornea  mainly  depend.  It  is  a  peculiar  modification  of  the  white 
fibrous  tissue,  continuous  with  that  of  the  sclerotic.  At  their  line  of 
junction,  the  fibres,  which  in  the  sclerotic  have  been  densely  inter- 
laced in  various  directions,  and  mingled  with  elastic  fibrous  tissue, 
flatten  out  into  a  membraneous  form,  so  as  to  follow  in  the  main  the 
curvatures  of  the  surfaces  of  the  cornea,  and  to  constitute  a  series  of 
more  than  sixty  lamellae,  intimately  united  to  one  another  by  very 
numerous  processes  of  similar  structure,  passing  from  one  to  the  other, 
and  making  it  impossible  to  trace  any  one  lamella  over  even  a  small 
portion  of  the  cornea.  The  resulting  areola?,  which  in  the  sclerotic 
are  irregular,  and  on  all  sides  open,  are  converted  in  the  cornea  into 
tubular  spaces,  which  have  a  very  singular  arrangement,  hitherto 
undescribed.  They  lie  in  superpose  planes,  the  continuous  ones  of 
the  same  plane  being,  for  the  most  part,  parallel,  but  crossing  those  of 
the  neighbouring  planes  at  an  angle,  and  seldom  communicating  with 
them.  The  arrangement  and  size  of  these  tubes  can  be  shown  by 
driving  mercury,  or  coloured  size,  or  air  into  a  small  puncture  made 
ill  the  cornea.  They  may  also  be  shown  under  a  high  power  by 
moistening  a  thin  section  of  a  dried  cornea,  and  opening  it  out  by 
needles."  In  addition  to  the  above  it  may  be  remarked,  that  the 
spaces  may  be  seen  without  injection,  or  any  other  preparation,  even 
in  perfectly  fresh  eyes. 

In  vertical  sections  of  the  cornea,  after  the  application  of  acetic 
acid,  the  nucleated  fibres  in  its  outer  or  denser  portion  are  seen  to 
follow  the  curved  form  of  the  cornea  itself,  while  in  its  inner  and  softer 
part  they  are  variously  disposed;  horizontal  sections  of  the  cornea, 
even  taken  from  the  surface,  exhibit  a  curved  and  interlaced  arrange- 

whether  treated  or  not  with  acetic  acid,  this  tissue  is  scarcely  to  he  traced,  the  nuclear 
form  of  fibrous  tissue  already  described,  and  which  is  so  very  abundant,  being  alone 
visible,  and  appearing  to  constitute  the  entire  of  its  substance.  If,  however,  a  small 
piece  of  the  inner  and  softer  part  of  the  cornea  be  torn  up  with  needles,  and  then 
examined,  bundles  of  fibrous  tissue,  very  analogous  to  those  of  the  white  fibrous 
form,  will  be  plainly  seen;  these  are  of  considerable  diameter,  reflect  a  greenish 
shade,  and  are,  in  many  parts,  transversely  straited,  each  filament  bearing  a  resemblance 
to  a  minute  Conferva ;  they  are  rendered  nearly,  though  not  quite,  invisible  by  the 
action  of  vinegar.  Considered  altogether,  the  cornea  resembles  very  closely,  in 
structure,  a  tendon,  which  also  contains  a  very  large  quantity  of  a  similar  nuclear 
fibrous  tissue. 


ORGANS     OF     THE     SENSES.  5  i  U 

ment  of  the  fibres ;  fibres,  also  nucleated,  pass  from  the  surtace  of  the 
cornea  deeply  into  its  substance :  the  use  of  these  is  doubtless  to  assist 
in  preserving  its  convexity.     (See  Plate  LX.Vll.Jig.  1.) 

The  posterior  elastic  lamina  is  the  third  layer  of  the  cornea:  it  is 
a  perfectly  transparent  membrane  of  appreciable  thickness,  so  that  it 
may  be  readily  recognised  with  the  unaided  sight,  and  is  but  slightly 
attached  to  the  cornea  proper. 

It  is  usually  described  as  structureless,  and  in  most  cases  it  certainly 
is  so;  but  in  the  human  eye  it  frequently  exhibits  peculiar  markings, 
portrayed  in  Plate  LXVII.  Jigs.  11,  12.  These,  however,  would 
appear  to  proceed  from  definite  inequalities  of  the  surface,  rather  than 
from  any  distinct  fibrous  or  cellular  tissue;  nevertheless,  the  appear- 
ances observed  are  remarkable,  and  worthy  of  record. 

This  lamina  preserves  its  transparency  even  in  boiling  water  and 
acetic  acid ;  and  a  further  peculiarity  is,  that  although  it  may  be  torn 
in  any  direction,  it  is  so  hard  that  it  can  be  bitten  through  only  with 
difficulty.  It  extends  to  the  margin  of  the  cornea  only,  where  it 
comes  into  connexion  with  certain  elastic  fibres  to  be  described 
hereafter. 

The  epithelium  of  the  aqueous  humour  is  the  fourth  layer  of  the 
cornea:  this  is  of  such  delicacy  and  tenuity  as  to  be  readily  over- 
looked; it  consists  of  angular  cells  which  form  a  tessellated  epithelium, 
and  rests  upon  the  posterior  surface  of  the  elastic  lamina  above 
described.  (See  Plate  LXVIII.  Jig.  11.)  This  epithelium  is  doubtless 
concerned  in  the  secretion  of  the  aqueous  humour,  but  it  does  not 
appear  to  extend  beyond  the  limits  of  the  elastic  lamina. 

The  fifth  layer,  to  which  reference  has  already  been  made,  is  the 
anterior  elastic  lamina,  which  is  described  in  the  third  part  of  "Physi- 
ological Anatomy,"  as  follows :  "  This  is  a  transparent  homogeneous 
lamina,  coextensive  with  the  front  of  the  cornea,  and  forming  the 
anterior  boundary  of  the  cornea  proper.  It  is  a  peculiar  tissue,  the 
office  of  which  seems  to  be  that  of  maintaining  the  exact  curvature  of 
the  front  of  the  cornea;  for  there  pass  from  all  parts  of  its  posterior 
surface,  and  in  particular  from  its  edge,  into  the  substance  of  the 
cornea  proper,  and  sclerotic,  a  multitude  of  filimentous  cords,  which 
take  hold,  in  a  very  beautiful  artificial  manner,  of  the  fibres  and  mem- 
branes of  those  parts,  and  serve  to  brace  them  and  hold  them  in  their 
right  configuration.  These  cords,  like  the  elastic  lamina  of  which 
they  are  productions,  appear  to  be  allied  to  the  yellow  element  of  the 
areolar  tissue.    They  are  unaffected  by  the  acids.    The  anterior  elastic 

33 


514  THE     SOLIDS. 

lamina  sustains  the  conjunctival  epithelium  which  covers  the  cornea, 
and  is  very  probably  a  representative  of  the  basement  membrane  of 
the  mucous  system,  as  it  occupies  the  corresponding  position  in  regard 
to  the  epithelium." 

The  writer  has  made  diligent  and  repeated  search  for  this  lamina, 
or  for  any  structure  resembling  it,  without  success,  however;  and  he 
has  no  hesitation  in  asserting  his  disbelief  in  the  existence  of  any 
membrane  in  the  slightest  degree  analogous  to  the  posterior  elastic 
lamina  in  the  situation  indicated:  he  is  not  prepared,  however,  to  deny 
the  presence  of  an  exceedingly  thin  layer  of  structureless  basement 
membrane,  although  of  this  even  he  has  not  yet  discovered  any 
evidence,  but  conceives  it  possible  that  it  may  exist.  Its  detection 
has  been  attempted  in  several  ways;  namely,  by  vertical  and  hori- 
zontal sections,  and  by  the  use  of  reagents,  but  to  no  purpose. 

In  a  representation  of  a  vertical  section  of  the  human  cornea,  given 
in  the  "Physiological  Anatomy,"  this  anterior  elastic  lamina  is 
represented  as  being  three  or  four  times  the  thickness  of  the  posterioi 
lamina,  so  that  there  ought  to  be  but  little  difficulty  in  its  detection, 
were  it  present  on  the  face  of  the  human  cornea. 

The  "elastic  cords"  mentioned  would  appear  to  be  nothing  more 
than  the  nucleated  fibres,  already  described  as  passing  in  a  curved 
manner  from  the  surface  of  the  cornea,  and  extending  deeply  into  its 
substance.     (See  Plate  LXVII.  fig.  1.) 

Choroid. 

The  next  membrane  met  with,  in  the  usual  order  of  dissection,  is 
the  choroid:  this  adheres  intimately  to  the  sclerotic  in  the  neighbour- 
hood of  the  larger  trunks  of  the  venae  vorticosse;  but  more  slightly  in 
the  intervals  between,  being  united  to  it  only  by  the  lamina  fusca. 

The  choroid  forms  a  thick  membrane,  externally  of  a  chocolate- 
colour,  flocculent  and  rough,  but  internally  of  a  bluish-black  colour, 
and  smooth  ;  its  substance  is  made  up  of  numerous  blood-vessels,  and 
of  an  immense  quantity  of  pigment  in  connexion  with  a  peculiar  form 
of  fibrous  tissue. 

The  tissue  of  which  the  choroid  is  composed,  has  been  hitherto 
stated  to  resemble  the  fibrous  tissue  of  the  sclerotic :  this  is  not  the 
case,  however,  as  indeed  might  have  been  inferred  from  the  ease  with 
which  it  tears,  especially  in  the  course  of  the  vessels,  and  the  absence 
of  bundles  of  fibres  on  the  torn  and  divided  margins:  the  fibrous 
element  of  the  choroid  is  of  a  peculiar  kind,  to  be  more  fully  described 
hereafter,  and  unlike  any  other  form  existing  in  the  human  body. 


ORGANS  OF  THE  SENSES.  515 

The  blood-vessels  of  the  choroid  are  usually  described  as  forming 
two  layers,  and  this  they  may  be  fairly  considered  as  doing,  although 
the  two  lamellae  are  not  perfectly  distinct  from  each  other,  being  con- 
nected by  numerous  blood-vessels  which  pass  between  them. 

These  laminae  may  be  designated  in  general  terms  separately  as 
arterial  and  venous ;  the  inner  or  arterial  lamina,  known  as  the  tunica 
Ruyschiana,  consists  of  a  dense  and  beautiful  plexus  of  vessels,  which 
are  so  closely  applied  to  each  other  as  scarcely  to  leave  any  inter- 
vening spaces  or  meshes.  (See  Plate  LXVII.  fig.  4.)  The  main 
arteries  which  supply  this  tunic,  and  the  veins  which  carry  off  its 
blood,  leave  it  by  numerous  points  on  its  outer  surface  only ;  the  veins 
are  particularly  large  and  numerous,  and  disposed  in  beautiful  curves, 
whence  they  are  called  venae  vorticosce.  (See  Plate  X.LYIII.  Jig.  2.) 
Before  leaving  the  choroid,  they  converge  to  form  four  or  five  principal 
trunks  which  enter  the  sclerotic;  the  arteries,  fewer  in  number  and 
much  smaller  in  size,  run  between  the  veins. 

An  immense  number  of  granular  nuclei  are  visible  in  the  walls  of 
the  venae  vorticosae. 

Stellate  Choroid  Epithelium. — Such  is  the  distribution  of  the  blood- 
vessels of  the  choroid :  the  next  most  important  element  in  its  consti- 
tution are  the  pigment  cells ;  these  exist  in  vast  quantities,  and  make 
up  much  of  its  substance ;  they  are  of  various  forms  and  sizes ;  but 
being  furnished  with  two,  three,  or  more  arms  or  radii,  they  may  be 
aptly  termed  stellate.  The  nucleus  in  each  cell  is  large  and  particu- 
larly clear,  appearing  almost  like  a  hole  in  its  centre:  this  is  owing  to 
the  absence  of  the  colouring  matter  contained  in  each  cell  in  that 
situation. 

The  existence  of  the  stellate  form  of  pigment  cells  in  the  human 
subject  appears  to  have  been  generally  overlooked:  it  was  described 
and  figured  in  Parts  VII.  and  VIII.  of  the  Microscopic  Anatomy,  pub- 
lished in  February  and  March,  1847,  and  its  arrangement  in  rows  was 
at  the  same  time  pointed  out;  its  position  in  the  choroid,  as  well  as  its 
structure,  have  since  been  examined  with  more  care,  and  with  the 
following  results : 

This  pigment  is  situated  beneath  the  tunica  Ruyschiana,  and  in  the 
intervals  between  the  venae  vorticosae,  which  it  accurately  fills  up,, 
some  of  the  arms  of  the  cells,  as  well  as  occasionally  a  few  of  the 
scattered  cells,  intrenching  upon  the  veins :  thus,  then,  its  disposition. 
is  a  counterpart  of  that  of  the  venae  vorticosae,  the  dense  rows  of  cells, 
exhibit  the  same  curves,  the  same  mode  of  branching*  and,  viewed 


516  THE     SOLIDS. 

altogether  with  a  low  object-glass  in  the  eyes  of  some  animals,  as  the 
sheep,  nothing  can  exceed  the  beauty  and  elegance  of  the  object  thus 
presented  to  our  examination.     (See  Plate  LXVIII.^°\  1.) 

With  regard  to  structure,  it  is  remarkable  that  each  radius,  or  arm 
of  the  cells  is  prolonged  into  a  colourless  fibre,  in  the  course  of  which 
several  other  cells  may  be  included.     (See  Plate  LXVIII.j^g-.  13.) 

This  structure  is  best  seen  in  the  lamina  fusca,  the  fibres  of  which 
are  all  of  this  nature,  and  are  exceedingly  diaphanous,  often  mem- 
branous, much  disposed  to  curl  up,  and  unaffected  by  distilled  vinegar, 
beyond  undergoing  a  degree  of  contraction.  All  the  fibres  met  with 
in  the  choroid,  except  those  entering  into  the  constitution  of  the 
blood-vessels,  are  of  this  peculiar  nature. 

The  inner  surface  of  the  choroid  is  so  smooth  as  to  convey  the 
impression  of  the  existence  of  a  distinct  membrane:  of  this,  however, 
no  satisfactory  evidence  has  yet  been  obtained,  although  portions  of 
membrane  apparently  devoid  of  structure,  have  been  seen  on  the 
margins  of  torn  portions  of  the  choroid.  If  a  membrane  does  really 
exist  in  this  situation,  it  is  possible  that  it  is  nothing  more  than  the 
vessels  of  the  tunica  Ruyschiana  'united  into  a  membrane  by  the 
fibres  above  described. 

Hexagonal  Choroidal  Epithelium. — On  the  inner  surface  of  the 
choroid  a  layer  of  cells  of  a  regularly  pentagonal,  or  hexagonal  form, 
filled  with  pigmentary  granules,  exists;  these  cells  are  so  coherent 
that  they  form  a  distinct  layer,  much  more  evident  in  the  eyes  of 
some  animals,  as  the  sheep,  and  pig,  than  in  those  of  man.  (See 
Plate  LXVIII.  fig.  12.) 

This  layer  extends  over  that  peculiar  structure  common  to  the  eyes 
of  many  quadrupeds  and  fishes,  the  tapetum  lucidum;  but  in  that 
situation  its  component  cells  are  of  smaller  size,  and  almost  entirely 
deprived  of  colouring  matter. 

In  albinoes  the  colouring  matter  is  deficient,  not  only  in  the  cells 
of  tapetum  lucidum,  but  also  in  those  of  the  hexagonal  and  stellate 
choroidal  epithelium. 

The  tapetum  lucidum  is  a  layer  of  fibrous  tissue  implanted  upon 
the  choroid,  possessing  the  remarkable  property  of  refracting  un- 
equally the  rays  of  light  which  fall  upon  it,  and  hence  its  brilliancy 
and  metallic  lustre:  acetic  acid  destroys  to  some  extent  this  pecu- 
liarity; the  stellate  pigment  is  continued  behind  the  tapetum  lucidum, 
which  singular  and  beautiful  structure  acts  as  a  concave  reflector, 
its  use  being  to  economize  light,  and  to  cause  the  rays  to  traverse  the 


ORGANS  OP  THE  SENSES.  517 

retina  a  second  time,  by  which  means  animals  possessing  it,  are 
enabled  to  discern  objects  in  a  light  which  would  be  insufficient  for 
the  purpose,  in  the  absence  of  such  a  provision. 

The  description  of  the  choroid  now  given,  includes  that  portion  of 
it,  only,  which  corresponds  to  the  retina,  and  which  ceases  at  a  line 
known  as  the  ora  serrata;  about  the  eighth  of  an  inch  behind  the 
margin  of  the  cornea,  in  front  of  this  line  as  far  as  the  iris,  the  choroid 
is  known  as  the  ciliary  body;  this  is  covered  behind  by  a  layer  of 
non-striated  muscular  fibre,  the  ciliary  muscle  (see  Plate  LXVIII. 
fig.  4),  and  from  it  the  ciliary  processes  descend. 

Ciliary  Processes. — These  processes,  usually  reckoned  at  about  sixty 
in  number,  are  received  into  corresponding  folds  or  plaitings  of  the 
hyaloid  membrane,  called  the  secondary  ciliary  processes,  and  which, 
taken  altogether,  form  a  circle  around  the  crystalline  lens,  named  after 
their  discoverer  the  Zone  of  Zinn:  they  are  each  composed  of  numer- 
ous blood-vessels,  (see  Plate  LXVII.  fig.  4),  fibrous  tissue,  irregular 
pigment  cells ;  and  "on  their  inner  surface  is  a  tough  colourless  lamina, 
composed  of  ill-defined  nucleated  cells  continuous  with  the  border  of 
the  retina,  but  clearly  not  composed  of  nervous  matter,  by  means  of 
which  they  are  immediately  connected  with  the  hyaloid  membrane." 

The  iris  may  be  regarded  as  an*  extension  of  the  choroid,  although 
it  does  not  exhibit  all  the  anatomical  characters  of  that  membrane; 
it  is  made  up  of  a  considerable  quantity  of  pigment  cells,  of  blood- 
vessels, and  of  fibres  of  unstriped  muscle.     (See  Plate  LXVIII.  j^g-.  9.) 

The  pigment  cells  constituting  the  posterior  layer  of  the  iris,  and 
called  uvea,  are  irregular  in  size  and  form,  as  are  those  also  situated 
among  the  fibres  of  the  iris;  upon  the  varieties  in  the  colouring 
matter  contained  in  these  last,  many  of  the  differences  observable  in 
the  iris  of  different  persons  and  animals  depend.     (See  Plate  LXVIII. 

fig-  14.) 

The  muscular  fibres  of  the  iris  in  the  human  subject,  are  of  the 
unstriped  kind,  and  follow  two  courses,  a  radiating  and  a  circular;  in 
birds,  however,  the  radiating  fibres  consist  of  striped  muscular  fibres, 
and  they  surround  immediately  the  pupil;  the  one  set  of  fibres  dilates 
the  pupil,  the  other  contracts  it. 

The  blood-vessels  of  the  iris  are  very  numerous,  and  are  derived 
chiefly  from  the  two  long  ciliary  arteries,  which,  on  approaching  the 
iris,  bifurcate  and  form  an  arch  around  it,  whence  pass  inwards  a 
number  of  branches  which  form  loops  near  the  pupillary  margin. 

"On  the  anterior  surface,  near  the  pupil,  avascular  circle  marks 


518  THE     SOLIDS. 

the  line  from  which  in  the  foetus  the  membrana  jmpillaris  stretched 
across  in  front  of  the  pupil.  This  membrane  at  that  early  period 
divides  the  posterior  from  the  anterior  chamber,  and  receives  from 
several  parts  of  the  circular  vessel  last  mentioned,  small  branches, 
which  approach  the  centre,  and  then  return  in  arches,  after  inoscula- 
ting sparingly  across  the  central  point."  The  membrana  pupillaris 
is  almost  absorbed  at  birth. 

The  iris,  according  to  the  authors  of  the  Physiological  Anatomy, 
"is  attached  all  around  at  the  junction  of  the  sclerotic  and  the  cor- 
nea, so  near  indeed  to  the  latter,  that  its  anterior  surface  becomes 
continuous  in  the  following  manner  with  the  posterior  elastic  lamina. 
This  lamina,  near  its  border,  begins  to  send  off  from  its  anterior  sur- 
face, or  that  towards  the  laminated  cornea,  a  net-work  of  elastic 
fibres,  which  stretch  towards  the  border,  becoming  thicker  as  they 
advance,  until  at  length  the  entire  thickness  of  the  lamina  is  expended 
by  being  converted  into  them.  These  fibres  then  bend  backwards 
from  the  wrhole  circumference  of  the  cornea,  to  the  circumference  of 
the  front  of  the  iris,  and  are  there  implanted,  passing  in  this  course 
across  the  line  of  the  anterior  chamber,  and  through  the  aqueous 
humour.  They  are  seen  more  easily  in  some  animals  than  in  others, 
forming  a  regular  series  of  pillars  ftround  the  anterior  chamber." 

It  would  appear,  however,  that  these  fibres,  which  may  be  readily 
detected  in  the  human  eye,  should  rather  be  described  as  proceeding 
from  the  sclerotic,  and  passing,  some  on  the  anterior  surface  of  the 
elastic  lamina,  and  others  on  the  front  of  the  iris,  thus  assisting  in 
uniting  these  parts  to  that  tunic;  it  is  very  doubtful  whether  they 
have  any  structural  connexion  with  the  posterior  elastic  lamina. 
(See  Plate  LXVIII.  fig.  8.) 

The  ciliary  nerves  pierce  the  ciliary  muscle  on  their  way  to  the  iris. 

Retina. 

We  come  in  the  next  place  to  the  description  of  the  most  interest- 
ing and  important  of  the  many  structures  which  enter  into  the  com- 
position of  the  globe  of  the  eye,  namely,  the  retina.  This  membrane 
may  be  regarded  as  the  expansion  of  the  optic  nerve,  to  which  certain 
other  structures  are  superadded,  and,  like  most  of  the  other  mem- 
branes of  the  eye,  is  divisible  into  distinct  lamellae ;  these,  reckoning 
from  without  inwards,  are,  tunica  Jacobi,  or  "stratum  bacillosum," 
the  granular  or  nuclear  layer,  the  ganglionary  layer,  the  vesicular 
layer,  the  fibrous  expansion  of  the  optic  nerve,  and,  lastly,  the  vascular 
expansion  of  the  arteria  centralis  retinae. 


ORGANS      OF     THE     SENSES.  519 

The  tunica  Jacobi  is  composed  of  a  single  stratum  of  cells  of  very 
remarkable  form.  They  are  minute  in  size,  several  times  longer  than 
broad,  having  their  long  axes  disposed  vertically  to  the  general  surface 
of  the  retina,  and  they  each  consist  of  a  body  or  head  of  a  more  or 
less  globular  or  oval  shape,  and  of  a  prolongation  or  tail,  four  or  five 
times  longer  than  the  head,  and  not  more  than  a  third  of  its  diameter. 
By  their  coherence  these  cells  form  a  distinct  membrane,  the  heads  of 
the  cells  all  being  directed  one  way,  namely,  towards  the  surface  of 
the  choroidal  epithelium,  and  the  tails  disposed  in  an  opposite  direc- 
tion. Although  these  cells  adhere  together  with  sufficient  firmness 
to  constitute  a  distinct  membrane,  it  would  appear  that  they  possess 
a  certain  power  of  movement  upon  each  other,  for  it  is  only  on  such 
a  supposition  that  we  can  explain  satisfactorily  the  fibrous  appearance 
which  this  membrane  frequently  presents  when  viewed  in  extenso. 
(See  Plate  LXVII.  fig.  9.) 

The  tunica  Jacobi,  although  certainly  not  a  nervous  structure,  is 
yet  properly  enumerated  as  one  of  the  layers  of  the  retina,  since  it 
never  adheres,  on  the  removal  of  the  latter  to  the  choroidal  epithelium, 
but  always  to  the  second  or  granular  layer  of  the  retina  itself:  on 
account  of  its  extreme  frailty  and  delicacy,  this  membrane  is  only  to 
be  satisfactorily  studied  in  extremely  fresh  eyes.  A  few  hours  after 
death  the  cells  separate  from  each  other,  and  the  heads  of  the  cells 
become  disjointed  from  the  tails,  so  that  in  the  course  of  a  short  time 
not  a  vestige  of  the  membrane  remains. 

Each  cell  of  the  stratum  bacillosum  bears  not  an  inexact  resemblance 
to  a  human  spermatozoon,  than  which  it  is,  however,  less  considerable 
in  size. 

The  granular  layer  consists  not  of  granules  merely,  as  the  name 
implies,  but  of  numerous  nuclei  imbedded  in  granular  matter,  and  each 
of  which  contains  several  dark  spots  which  reflect  the  light  strongly. 
This  layer  is  of  considerable  thickness,  and  is  described  in  the  "  Physi- 
ological Anatomy"  as  being  divided  into  two,  of  which  the  inner  is 
much  the  narrower,  by  a  pale  stratum  which  can  only  be  seen  hj  very 
careful  manipulation.  The  nuclei  of  which  it  is  composed  bear  much 
resemblance  to  those  which  occur  in  the  convolutions  of  the  brain,  and 
are  most  probably  of  the  same  nature.     (See  Plate  LXVII.  Jigs.  5,  6.) 

The  next  is  the  ganglionary  layer:  this  appears  to  have  been 
hitherto  altogether  overlooked ;  its  discovery  supplies  a  desideratum 
in  the  anatomy  of  the  eye,  and  clearly  shows  the  really  nervous  char- 
acter of  the  granular  and  vesicular  strata  of  the  retina,  which  many 
persons  have  been  much  disposed  to  doubt. 


520  THE     SOLIDS. 

This  layer  is  exceedingly  thin  and  delicate,  hardly  indeed  to  be  con- 
sidered as  a  distinct  stratum,  but  yet  consisting  of  numerous  caudate 
ganglionary  globules,  in  every  respect  similar,  in  point  of  structure,  to 
those  which  have  been  described  as  occurring  in  so  many  of  the 
ganglia  of  the  human  brain. 

These  caudate  cells  differ  considerably  in  size,  but  yet  are  all 
referable  to  one  of  two  standards,  the  larger  very  much  exceeding  the 
smaller  in  dimensions.     (See  Plate  LXVII.  fig.  8.) 

It  is  in  the  human  retina  only  that  these  cells  have  as  yet  been 
detected. 

The  fourth  or  vesicular  layer  lies  immediately  on  the  outer  surface 
of  the  fibrous  layer :  the  cells  composing  it  are  several  times  larger 
than  the  nuclei  of  the  granular  layer;  a  few  of  the  most  external  of 
them  are  granular  and  nucleated,  but  the  majority,  and  these  the  larger 
cells,  are  clear  and  transparent  as  water,  perfectly  globular,  and  without 
appreciable  nuclei.  The  cells  of  the  vesicular  layer  resemble  very 
closely  the  delicate  cells  which  have  been  described  in  a  previous  part 
of  this  work,  as  found  in  the  fibrous  portions  of  the  human  brain.  (See 
Plate  LXVII.  fig.  7.) 

The  fibrous  gray  layer  is  best  seen  and  most  strongly  marked  in 
the  retina,  near  to  the  optic  nerve.  If  a  portion  of  this  membrane  be 
cut  off  and  spread  out  upon  glass,  it  will  be  seen  to  present,  viewed 
with  the  inch  or  half-inch  object-glass,  a  number  of  parallel  or  rather 
radiating  flattened  bands,  two  of  which  occasionally  divide  or  bifurcate. 

If,  in  the  next  place,  these  bands  or  bundles,  having  been  separated 
somewhat  from  each  other  by  means  of  needles,  and  as  much  of  the 
granular  layer  which  so  obscures  them  washed  away  with  a  camel's- 
hair  brush  as  possible,  be  then  examined,  they  will  each  be  observed  to 
present  a  fibrous  appearance;  and, on  a  prolonged  and  careful  exami- 
nation, it  will  become  apparent  that  they  are  made  up,  first,  of  a  small 
quantity  of  nucleated  fibrous  tissue;  and,  secondly,  and  principally,  of 
gray  gelatinous  nerve  fibres.     (See  Plate  LXVIII.  fig.  6.) 

That  these  gelatinous  fibres  constitute  the  principal  portion  of  the 
fibrous  layer  of  the  retina,  and  that  no  tubular  nerve  fibres  exist  in 
the  retina  itself,  are  points  upon  which  not  the  smallest  doubt  can  be 
entertained. 

Of  the  reality  of  the  transformation  of  the  tubular  into  the  gelatinous 
nerve  filament ;  that  is,  the  conversion  of  a  tubular,  unbranched,  and 
unnucleated  structure  into  a  branched  and  nuclear  tissue,  great  mis- 
givings might  be  well  entertained;  an  attentive  study  of  the  structure 


ORGANS  OF  THE  SENSES.  521 

of  the  fibrous  gray  layer  of  the  retina  renders  it  very  difficult,  however, 
to  deny  the  reality  of  such  a  structural  transition. 

The  vascular  lamina  is  the  last  of  the  layers  of  the  retina:  it  would 
appear  to  be  entirely  distributed  upon  the  inner  surface  of  the  fibrous 
layer;  for,  if  we  take  a  perfectly  fresh  eye,  and  spread  the  retina  out 
with  its  inner  surface  upwards,  we  can  readily  see  the  larger  blood- 
vessels filled  with  blood  corpuscles,  and  having  the  fibrous  layer  situ- 
ated immediately  behind  them.     (See  Plate  LXVII.  fig.  2.) 

The  optic  nerves  consist  of  several  bundles  of  nerve  tubules  :  these 
are  very  slender  and  brittle,  and  interspersed  with  delicate  globular 
cells ;  in  these  last  two  particulars,  these  nerves  correspond  with  the 
white  fibrous  portions  of  the  brain. 

The  transparent  media  of  the  eye  are  the  vitreous  body  and  the 
crystalline  lens  with  its  capsule. 

Vitreous  Body. 

The  vitreous  humour  is  enclosed  in  a  perfectly  structureless  and 
exceedingly  delicate  membrane,  called  the  hyaloid  membrane:  this 
does  not  enclose  the  whole  of  the  vitreous  humour,  but  is  deficient 
behind  the  crystalline  lens,  it  being  inserted  into  the  side  of  the  capsule 
of  that  body. 

From  all  points  of  the  inner  surface  of  this  membrane  fibres  proceed; 
these  interlace  with  each  other  in  such  a  manner  as  to  form  a  cellated 
structure. 

The  size  and  structure  of  these  cells  may  be  readily  seen  with  an 
inch  or  half-inch  object-glass;  and  the  best  view  of  them  is  obtained 
in  the  neighbourhood  of  the  zona  ciliaris.     (Plate  LXVIII.  fig.  7.) 

Granular  nuclei  of  large  size  are  seen  on  the  walls  of  the  cellated 
spaces;  these  are  most  probably  concerned  in  the  secretion  of  the 
vitreous  humour.  That  these  several  cellated  spaces  communicate 
with  each  other,  seems  proved  by  the  fact  that  if  the  hyaloid  mem- 
brane be  ruptured,  the  whole  of  the  vitreous  humour  will  gradually 
escape  through  the  aperture. 

A  layer  of  cells  of  large  size,  and  of  such  extreme  transparency ; 
as  to  be  discovered  only  with  great  difficulty,  are  described  in  the 
"Physiological  Anatomy"  as  situated  on  the  hyaloid  membrane, 
between  it  and  the  retina :  these  have  not  fallen  under  the  observation 
of  the  writer. 

The  vitreous  body,  then,  consists  of  the  hyaloid  membrane,  cellated 
fibrous   structure,  the   zone  of  Zinn,  and  of  the  vitreous  humour. 


522  THE     SOLIDS. 

Through  the  centre  of  tms  body  a  branch  of  the  central  artery  of  the 
retina  passes  in  early  life,  destined  for  the  posterior  part  of  the  capsule 
of  the  lens. 

Crystalline  Lens. 

The  cr-ystalline  lens  is  composed  of  capsule  and  body. 

The  capsule  is  formed  of  a  thin  lamella  of  elastic  tissue,  much  thicker 
before  than  behind,  but  in  all  essential  particulars  similar  to  the  poste- 
rior elastic  lamina  of  the  cornea.  The  manner  in  which  it  is  attached 
to  the  hyaloid  membrane  has  been  already  pointed  out;  it  now  remains 
to  observe  that  the  cellated  fibres  of  the  vitreous  body  are  also  inserted 
into  its  posterior  part.  It  is  perfectly  closed  on  all  sides,  so  that  in 
the  adult  condition  of  the  eye  neither  vessels  nor  nerves  pass  through 
it  to  the  lens. 

The  body  of  the  lens,  transparent  and  jelly-like  as  it  appears  to  the 
unaided  sight,  is  yet  full  of  elaborate  and  elegant  structure.  It  consists 
of  very  many  layers  of  concentric  lamellae  of  flattened  fibres,  which 
radiate  from  the  centre,  and  are  disposed  in  a  parallel  manner  with 
reference  to  each  other;  the  fibres,  however,  have  a  more  complicated 
arrangement  than  this,  as  will  be  evident  from  what  follows. 

In  the  Mammalia  in  general,  there  are  visible  on  the  front  surface 
of  the  lens,  when  this  has  slightly  lost  its  transparency,  three  radiating 
grooves  or  lines,  the  points  of  which  terminate  at  about  one-third 
from  the  border  of  the  lens.  On  the  opposite  surface  of  the  lens 
there  exist  three  similar  lines,  occupying  an  intermediate  position. 
From  these  lines  the  fibres  pass  from  the  one  surface  on  to  the  other ; 
thus  a  fibre  which  starts  from  the  point  of  one  of  the  lines  in  front, 
passes  over  the  border  of  the  lens,  advances  midway  between  two 
lines  on  the  opposite  surface,  and  is  inserted  in  the  angle  of  division 
of  those  lines;  another  fibre  starting  from  between  two  lines  in  front, 
is  lost  on  the  extremity  of  a  line  situated  posteriorly :  the  rest  of  the 
fibres  occupy  positions  intermediate  to  these.  If,  in  the  next  place, 
we  bear  in  mind  the  fact  that  these  lines,  seen  on  the  surface  of  the 
lens,  are  but  the  edges  of  planes  which  pass  through  the  centre  of 
the  lens,  affording  points  of  divergence,  and  concourse  for  all  the 
fibres,  deep  as  well  as  superficial,  we  shall  readily  comprehend  what, 
without  this  explanation,  would  have  appeared  an  intricate  arrange- 
ment; and  we  shall  perceive  why  it  is  that  the  lens,  when  hardened 
in  spirit,  or  boiled  in  water,  is  prone  to  separate  into  concentric  lamellae, 
and  into  three  triangular  segments.     From  the  above  arrangement  it 


ORGANS  OF  THE  SENSES.  523 

results,  also,  that  all  the  fibres,  whether  superficial  or  deep-seated, 
decrease  in  width  as  they  approach  the  centre  of  the  lens  on  either 
surface,  and  also  that  the  superficial  are  longer  and  larger  than  the 
deeper  seated.     (See  Plate  LXVII.  fig.  13.) 

The  edges  of  the  fibres  are  most  beautifully  toothed  and  dovetailed 
together,  as  was  first  pointed  out  by  Sir  David  Brewster.  This 
toothing  is  best  seen  in  the  eye  of  fishes;  it  is  also  clearly  manifest, 
although  on  a  smaller  scale,  in  the  fibres  of  the  lens  of  most  mammalia 
and  of  man.     (See  Plate  LXVII.  fig.  10.) 

On  the  surface  of  the  lens  beneath  the  capsule,  and  occupying  the 
space  between  these,  a  delicate  epithelium  exists,  very  similar  to  that 
on  the  posterior  elastic  lamina.  (See  Plate  ~L~XN\\\.  fig.  10.)  After 
death,  this  space  is  occupied  by  a  small  quantity  of  fluid,  the  liquor 
Morgagni. 

Beneath  this  epithelium,  again,  other  small  oval  granular  cells  are 
encountered ;  from  these  possibly  the  fibres  of  the  lens  take  their 
origin. 

The  lens  is  of  less  density  externally  than  internally ;  this,  is  also 
one  of  the  results  of  the  peculiar  form  and  arrangement  of  the  fibres. 

In  the  adult  eye,  the  lens  is  entirely  destitute  of  blood-vessels, 
although  during  its  development  in  the  foetus  it  is  copiously  supplied 
with  them. 

THE    ORGAN    OF    HEARING. 

Elaborate  as  is  the  organization  of  the  ear,  it  yet  presents  less 
to  interest  the  microscopical  anatomist,  than  many  other  of  the 
organs  which  enter  into  the  composition  of  the  human  fabric.  The 
ear  is  divisible  into  three  portions — the  limits  of  each  of  which  are 
well  defined — an  external,  a  middle,  and  an  internal:  the  external 
portion  is  an  apparatus  for  the  collection  of  sound;  the  middle  is 
designed  for  its  conveyance  to  the  internal,  or  true  and  essential 
division  of  the  organ  of  hearing. 

The  External  Ear. 

The  external  ear  consists  of  the  expanded  part  or  auricle,  and  the 
external  meatus. 

The  Auricle. — The  auricle  presents  several  eminences  and  depres- 
sions, many  of  which  have  received  distinct  names;  it  is  made  up  of 
integument,  cartilages,  and  fat;  the  integument  is  thin  and  delicate, 
and  is  furnished  with  but  few  sebaceous  glands;  the  cartilages  are  of 


524  THE     SOLIDS. 

the  fibrous  kind,  and  are  three  in  number — the  larger  forming  the 
pinna,  being  separated  from  that  of  the  tragus  and  anti-tragus,  by 
grooves  filled  up  with  fibrous  tissue ;  lastly,  the  fat  is  situated  chiefly 
in  the  lobe  of  the  ear.  Ligamentous  bands  bind  the  auricle  to  the 
bone,  while  its  movements  are  effected,  in  part,  by  muscular  fibres 
which  pass  between  the  prominent  parts  of  its  constituent  cartilages, 
but  mainly,  by  three  small  muscles  of  the  striped  variety,  and  each 
of  which,  has  received  a  distinct  name. 

The  Auditory  Canal. — The  auditory  canal  consists  of  two  parts — 
a  cartilaginous  and  an  osseous ;  the  first  is  formed  by  the  prolongation 
inwards  of  the  cartilages  of  the  auricle;  these  form  a  tube,  deficient 
at  the  upper  and  back  part,  where  the  place  of  cartilage  is  supplied 
by  a  fibrous  membrane ;  this  tube  is  inserted  into  the  auditory  pro- 
cess of  the  temporal  bone ;  the  osseous  part  of  this  canal  is  formed 
by  the  auditory  process  already  alluded  to ;  this  process  in  the  adult 
is  nearly  three-quarters  of  an  inch  long,  and  to  its  outer  margin  the 
tympanum  is  attached,  the  bone  being  grooved  for  its  reception:  in 
the  fetus,  the  auditory  process  is  a  detached  ring  of  bone,  into  which, 
however,  the  tympanum  is  inserted. 

The  orifice  of  the  meatus  is  defended  by  hairs,  the  bases  of  which 
are  in  connexion  with  sebaceous  glands;  still  further  inwards,  but 
limited  to  the  cartilaginous  part  of  the  passage,  the  ceruminous  glands 
are  encountered:  these  have  already  been  described. 

According  to  some  observers,  muscular  fibres  exist  in  the  external 
meatus,  which  becomes  shortened  by  their  contraction. 

The  Middle  Ear. 

The  middle  ear  consists  of  the  tympanum,  tympanic  cavity,  and 
the  ossicles  with  their  muscles. 

The  tympanum,  or  tympanic  membrane,  is  divisible  into  three 
laminae — an  external  or  cuticular,  a  middle  or  fibrous,  and  an  internal 
or  ciliated ;  the  external  is  a  continuation  of  the  cuticle  which  lines 
the  external  meatus,  and  may  be  separated  as  a  distinct  membrane : 
the  fibrous  tissue,  of  which  the  internal  lamina  of  the  tympanum  is 
composed,  is  strong  and  dense,  and  is  arranged  in  a  radiated  manner; 
into  this  the  handle  of  the  malleus  is  inserted :  the  blood-vessels  which 
supply  the  tympanum  pass  along  the  handle  of  the  above-named 
bone,  and  follow  the  same  radiated  course  as  the  fibres  themselves ; 
the  inner  and  third  lamina  is  composed  of  cells  of  ciliated  epithelium, 
similar  to  those  lining  the  tympanic  cavity. 


ORGANS  OF  THE  SENSES.  525 

The  tympanic  cavity  is  lined  by  a  fibrous  membrane,  divisible 
into  two  layers;  the  fibres  entering  into  the  composition  of  one  of 
these,  follow  a  longitudinal  course,  while  those  of  the  other  layer  are 
circularly  disposed;  these  fibres  are,  for  the  most  part,  nucleated,  and 
would  appear  to  be  of  the  elastic  kind:  in  the  longitudinal  layer,  the 
fibres  are  disposed  in  bundles,  and  are  possibly  contractile:  on  the 
surface  of  this  membrane,  and  lining  immediately  the  tympanic  cavity, 
is  a  layer  of  ciliated  epithelium,  continuous  on  the  one  hand  with  that 
of  the  tympanic  membrane ;  and  on  the  other,  with  that  clothing  the 
interior  surface  of  the  Eustachian  tube. 

Posteriorly,  the  tympanic  cavity  exhibits  the  openings  of  the  mastoid 
cells;  anteriorly,  the  orifice  of  the  Eustachian  tube  may  be  noticed, 
while  the  internal  wall  of  the  tympanum  presents  two  orifices  which 
communicate  with  the  internal  ear:  these  are  the  fenestra  ovalis,  leading 
into  the  vestibule;  and  the  fenestra  rotunda,  opening  into  the  cochlea. 

The  whole  length  of  the  tympanic  cavity,  is  traversed  by  a  chain 
of  three  bones,  united  to  each  other  by  muscles  of  the  striped  kind; 
one  extremity  of  this  chain  is  attached,  as  already  noticed,  to  the 
tympanum,  while  the  other,  formed  by  the  base  of  the  stapes,  is  in 
connexion  with  the  fenestra  ovalis. 

In  the  tympanic  cavity  of  the  ear  of  the  sheep  cells,  containing 
pigment,  may  very  generally  be  observed;  among  these,  I  have 
noticed  the  occurrence  of  numerous  delicate  transparent  cells,  similar 
to  those  of  the  white  substance  of  the  brain  and  spinal  marrow. 

The  Internal  Ear  or  Labyrinth. 

The  internal  ear,  which  is  the  essential  portion  of  the  organ  of 
hearing,  consists  of  three  parts:  the  vestibule,  the  semi-circular 
canals,  and  the  cochlea;  these  are  cavities  imbedded  in  the  petrous 
bone,  communicating  with  the  tympanic  cavity  on  the  one  side,  by  the 
fenestras  ovalis  and  rotunda;  and  on  the  other,  with  the  internal  audit- 
ory canal.  The  dense  bone  immediately  surrounding  these  cavities  is 
termed  the  osseous  labyrinth,  in  contra-distinction  to  the  membranous 
labyrinth  contained  within  them.  The  description  of  the  form,  &c, 
of  the  osseous  labyrinth  belongs  rather  to  descriptive  than  to  general 
or  microscopic  anatomy,  and  therefore  will  not  here  be  entered  upon. 

The  osseous  labyrinth  contains  a  fluid  which  has  been  called  the 
perilymph,  from  its  surrounding,  though  in  the  vestibule  and  semi- 
circular canals  only,  a  hollow  membranous  apparatus — the  membran- 
ous labyrinth,  which  itself  contains  a  fluid,  the  endolymph. 


526  THE     SOLIDS. 

The  following  account  of  the  structure  of  the  spiral  lamina  ;  of  the 
cochlea ;  the  cochlear  muscle ;  the  cochlear  nerves ;  the  membran- 
ous labyrinth ;  the  vestibular  and  auditory  nerves,  is  copied  from  the 
"Physiological  Anatomy:" 

Of  the  Structure  of  the  Spiral  Lamina  of  the  Cochlea. — "We 
shall  term  the  two  surfaces  of  this  lamina,  tympanic  and  vestibular, 
as  they  regard,  respectively,  the  tympanic  or  vestibular  scala.  The 
osseous  portion  of  the  spiral  lamina  extends  more  than  half  way  from 
the  modiolus  towards  the  outer  wall,  and  is  perforated,  as  already 
described,  by  a  series  of  plexiform  canals,  for  the  transmission  of  the 
cochlear  nerves ;  these  canals,  taken  as  a  whole,  lie  close  to  the  lower 
or  tympanic  surface,  and  open  at  or  near  the  margin  of  this  zone. 
The  vestibular  surface  of  the  osseous  zone  presents,  in  about  the 
outer  fifth  of  its  extent,  a  remarkable  covering,  more  resembling  the 
texture  of  cartilage  than  any  thing  else,  but  having  a  peculiar  arrange- 
ment, quite  unlike  any  other  with  which  we  are  acquainted.  Being 
uncertain  respecting  the  office  of  this  structure,  we  shall  term  it  the 
denticulate  lamina  (Plate  LXIX.  fig.  3),  from  a  beautiful  series  of 
teeth,  forming  its  outer  margin,  which  project  far  into  the  vestibular 
scala,  and  in  the  first  coil,  terminate  almost  on  a  level  with  the 
margin  of  the  osseous  zone,  but  more  within  this  margin  towards  the 
apex  of  the  cochlea.  They  thus  constitute  a  kind  of  second  margin 
to  the  osseous  zone,  on  the  vestibular  side  of  the  true  margin,  and 
having  a  groove  beneath  them,  which  runs  along  the  whole  lamina 
spiralis,  in  the  vestibular  scala,  immediately  above  the  true  margin  of 
the  osseous  zone.  The  intervals  between  the  teeth,  are  to  be  seen  on 
their  upper  surface,  on  their  free  edge,  and  also  within  this  groove,  so 
that  the  teeth  are  wedge-shaped,  and  their  upper  and  under  surfaces, 
traced  from  the  free  edge,  recede.  The  free  projecting  part,  or  teeth 
of  the  denticulate  lamina,  form  less  than  a  fourth  of  its  entire  breadth, 
and  in  the  remainder  of  its  extent,  it  appears  to  rest  on  the  osseous 
zone ;  seen  from  above,  after  the  osseous  zone  has  been  rendered  more 
transparent  by  weak  hydro-chloric  acid,  rows  of  clear  lines  may  be 
traced  from  the  teeth  at  the  convex  edge,  towards  the  opposite  or 
concave  edge  of  the  lamina  These  lines  appear  to  be  a  structure 
resembling  that  of  the  teeth  themselves,  and  they  are  separated  from 
one  another  by  rows  of  clear,  highly  refracting  granules,  which  render 
the  intervals  very  distinct.  These  intervals  are  more  or  less  sinuous 
and  irregularly  branched. 


ORGANS  OF  THE  SENSES.  527 

"  The  denticulate  lamina,  thus  placed  on  the  vestibular  surface  of 
the  osseous  zone,  is  above,  and  at  some  distance  from  the  plexus  of 
the  cochlear  nerves,  which  lies  near  its  tympanic  surface.  The  vesti- 
bular surface  of  the  osseous  zone,  including  the  denticulate  lamina,  is 
convex,  rising  from  the  free  series  of  teeth  towards  the  modiolus. 

"In  the  groove  already  mentioned,  there  is  a  series  of  elongated 
bodies,  not  unlike  columnar  epithelium,  in  which  the  nuclei  are 
very  faint. 

"  These  bodies  are  thick  and  tubical  at  one  end,  and  taper  much 
towards  the  other.  They  are  united  in  a  row,  and  it  is  possible  they 
may  have  some  analogy  to  the  club-shaped  bodies  of  Jacob's  mem- 
brane.    We  can  assign  them  no  use. 

"Continuous  with  the  thin  margin  of  the  osseous  zone  is  the  mem- 
branous zone.  (Plate  LXIX.  Jig.  4.)  This  is  a  transparent  glassy 
lamina,  having  some  resemblance  to  the  elastic  laminae  of  the  cornea, 
and  the  capsule  of  the  lens.  A  narrow  belt  of  it,  next  the  osseous 
zone,  is  smooth,  and  exhibits  no  internal  structure,  while,  in  the  rest 
of  its  width,  it  is  marked  by  a  number  of  very  minute  straight  lines, 
radiating  outwards  from  the  side  of  the  modiolus.  These  lines  are 
very  delicate  at  their  commencement,  become  more  strongly  marked 
in  the  middle,  and  are,  again,  fainter  ere  they  cease,  which  they  do  at 
a  curved  line  on  the  opposite  side.  Beyond  this,  the  membranous 
zone  is,  again,  clear  and  homogeneous,  and  receives  the  insertion  of 
the  cochlearis  muscle.  The  inner  clear  belt  of  the  membranous  zone 
is  little  affected  by  acids;  it  seems  hard  and  brittle.  The  middle  or 
pectinate  portion  is  more  flexible,  and  tears  in  the  direction  of  the 
lines.  The  outer  clear  belt  is  swollen,  and  partially  destroyed  by  the 
action  of  acetic  acid.  Along  the  inner  clear  belt,  and  on  its  tympanic 
surface,  runs  a  single,  sometimes  branched  vessel,  which  would  be 
most  correctly  called  a  capacious  capillary,  as  it  resembles  the  capil- 
laries in  the  texture  of  its  wall,  but  exceeds  them  in  size.  It  is  the 
only  vessel  supplied  to  the  membranous  zone,  and  seems  to  be  thus 
regularly  placed,  that  it  may  not  mar  the  perfection  of  the  part  as  a 
recipient  and  propagator  of  sonorous  vibrations." 

Of  the  Cochlearis  Muscle. — "At  its  outer  or  convex  margin,  the 
membranous  zone  is  connected  to  the  outer  wall  by  a  semi-transpa- 
rent structure.  This  gelatinous-looking  tissue  was  observed  by 
Breschet,  and  is,  indeed,  very  obvious  on  opening  the  cochlea;  but 
we  are  not  aware  of  any  one  having  hinted  at  what  we  regard  to  be 
its  real  nature.     The  outer  wall  of  the  cochlea  presents  a  groove, 


THE     SOLIDS 


ascending  the  entire  coil,  opposite  the  osseous  zone  of  the  lamina 
spiralis,  and  formed  principally  by  a  rim  of  bone,  which,  in  section, 
looks  like  a  spur,  projecting  from  the  tympanic  margin  of  the  groove, 
the  opposite  margin  being  very  slightly  or  not  at  all  marked.  This 
groove  diminishes  in  size  towards  the  apex  of  the  cochlea.  It  gives 
attachment  to  the  structure  in  question,  by  means  of  a  firm  dense  film 
of  tissue,  having  a  fibrous  character,  and  the  fibres  of  which  run 
lengthwise  in  the  groove,  and  are  intimately  united  to  it,  especially 
along  the  projecting  rim.  From  this  cochlear  ligament,  the  cochlearis 
muscle  passes  to  the  margin  of  the  membranous  zone,  filling  the 
groove  and  projecting  into  the  canal,  so  as  to  assist  in  dividing  the 
tympanic  and  vestibular  scalae  from  one  another,  and  thus  forming,  in 
fact,  the  most  external  or  the  muscular  zone  of  the  spiral  laminae. 
Thus  the  cochlear  muscle  is  broad  at  its  origin  from  the  groove  of 
bone,  and  slopes  above  and  below  to  the  thin  margin  in  which  it  ter- 
minates, so  that  its  section  is  triangular,  and  it  presents  three  surfaces, 
one  towards  the  groove  of  bone,  and  one  to  each  of  the  scalee.  The 
surface  towards  the  vestibular  scala  is  much  wider  than  that  towards 
the  tympanic  scala,  and  presents,  in  a  band  running  parallel  to  and 
at  a  short  distance  from  the  margin  of  the  membranous  zone,  a  series 
of  arched  vertical  pillars  with  intervening  recesses,  much  resembling 
the  arrangement  of  the  musculi  pectinati  of  the  heart.  (Plate  LXIX. 
fig.  5.)  These  lead  to,  and  terminate  in,  the  outer  clear  belt  of  the 
membranous  zone,  which  forms  a  kind  of  tendon  to  the  muscle.  This 
entire  arrangement  is  almost  sufficient  of  itself  to  determine  the  mus- 
cular nature  of  the  structure.  If  its  fibres  were  of  the  striped 
variety,  no  doubt  would  remain :  but  its  mass,  evidently  fibrous,  is 
loaded  with  nuclei,  and  filled  with  capillaries,  following  the  direction 
of  the  fibres,  and  in  almost  all  respects  it  has  the  closest  similarity  to 
the  ciliary  muscle  of  the  eye. 

"The  capillaries  of  the  ciliary  muscle  are  derived  from  vessels 
meandering  over  the  walls  of  the  scala  before  entering  it,  and  those 
from  above  and  below  do  not  anastomose  across  the  line  of  attach- 
ment of  the  membranous  zone ;  thus  indicating  that  the  continuation 
of  this  zone  enters  as  a  plane  of  tendon  into  the  interior  of  the  muscle, 
dividing  it  into  two  parts,  and  receiving  the  fibres  in  succession. 

"  The  scalse  of  the  cochlea  are  lined  with  a  nucleated  membrane,  or 
epithelium,  which  is  very  delicate,  and  easily  detached,  usually  more 
easily  seen  in  the  vestibular  than  in  the  tympanic  scala,  and  in  many 
animals  containing  scattered  pigment" 


ORGANS  OF  THE  SENSES.  529 

Of  the  Cochlear  Nerves. — "  These  enter  from  the  internal  auditory 
meatus  through  the  spirally  arranged  orifices  at  the  base  of  the  modiolus, 
and  turn  over  in  succession  into  the  canals  hollowed  in  the  osseous 
zone  of  the  spiral  lamina,  close  to  its  tympanic  surface.  In  this 
distribution,  the  nervous  bundles  sub-divide  and  reunite  again  and 
again,  forming  a  plexus  with  elongated  meshes,  the  general  radiating 
arrangement  of  which  may  be  readily  seen  through  the  substance  of 
the  bone  when  it  has  been  steeped  in  diluted  hydro-chloric  acid. 
(Plate  LXIX.  fig.  6.)  Towards  the  border  of  the  osseous  zone,  the 
bundles  of  the  plexus  are  smaller  and  more  closely  set,  so  as  at  length 
almost  to  form  a  thin  uniform  layer  of  nervous  tubules.  Beyond  the 
border,  and  partially  on,  or  in  the  inner  transparent  belt  of  the  mem- 
branous zone,  these  tubules  arrange  themselves  more  or  less  evidently 
into  small  sets,  which  advance  a  short  distance,  and  then  terminate 
much  on  the  same  level.  These  terminal  sets  of  tubules  are  cone- 
shaped,  coming  to  a  kind  of  point  ere  they  cease.  The  white  sub- 
stance of  Schwann  exists  in  them  throughout,  but  is  thrown  into 
varicosities,  and  broken  with  extreme  facility,  and  they  are  inter- 
spersed with  nuclei,  so  that  it  is  very  difficult  to  discover  the  precise 
disposition  of  the  individual  tubules.  They  seem  to  cease,  one  after 
another,  thus  causing  the  set  to  taper;  and  at  least  it  appears  certain 
that  evidence  of  loopings,  such  as  have  been  described  by  some,  is 
wanting.  In  the  cochlea  of  the  bird,  however,  we  have  seen  at  one 
end,  a  plexiform  arrangement  of  nucleated  fibres  ending  in  loops;  but 
this  is  a  peculiar  structure. 

"The  capillaries  of  the  osseous  zone  are  most  abundant  on  the 
tympanic  scala,  in  connexion  with  the  nerves  now  mentioned,  and  form 
loops  near  the  margin,  with  here  and  there  an  inosculation  with  the 
large  marginal  capillary  already  mentioned." 

Of  the  Membranous  Labyrinth. — "  This  has  the  same  general 
shape  as  the  bony  cavities  in  which  it  lies,  but  is  considerably  smaller, 
so  that  the  perilymph  intervenes  in  some  quantity,  except  where  the 
nerves  passing  to  it  confine  it  in  close  contact  with  the  osseous  wall. 
Its  vestibular  portion  consists  of  two  sacs,  viz:  a  principal  one  of 
transversely  oval  figure,  and  compressed  laterally,  called  the  utriculus, 
or  common  sinus,  occupying  the  upper  and  back  part  of  the  cavity, 
in  contact  with  the  fovea  semi-elliptica,  and  beneath  this  a  smaller 
and  more  globular  one,  the  sacculus,  lying  in  the  fovea  hemispherica, 
near  the  orifice  of  the  vestibular  scala  of  the  cochlea,  and  probably- 
communicating  with  the  utriculus. 

34 


530  THE     SOLIDS. 

"  The  membranous  semi-circular  canals  have  the  same  names, 
shape,  and  arrangement  as  the  osseous  canals  which  enclose  them,  but 
are  only  a  third  of  the  diameter  of  the  latter.  As  the  osseous  canals 
open  into  the  vestibule,  so  the  membranous  ones  open  at  both  ends 
into  the  utriculus,  there  being,  however,  a  constricted  neck  between 
this  sac  and  the  ampullated  extremity  of  each  canal.  The  auditory 
nerve  sends  branches  to  the  utriculus,  to  the  sacculus,  and  to  the 
ampulla  of  each  membranous  canal.  These  nerves  enter  the  vesti- 
bule by  the  minute  apertures  before  described,  and  tie  down,  as  it 
were,  both  the  utriculus  and  sacculus  to  the  osseous  wall  at  those 
points,  the  membrane  being  much  thicker  and  more  rigid  at  those 
parts.  The  branches  to  the  ampulla  of  the  superior  vertical  and  the 
horizontal  semi-circular  canals,  enter  the  vestibule  with  the  utricular 
nerve,  and  then  cross  to  their  destinations,  while  that  to  the  ampulla 
of  the  posterior  vertical  canal,  traverses  the  posterior  wall  of  the 
cavity,  and  opens  directly  into  the  ampulla. 

"  The  wall  of  the  membranous  labyrinth  is  translucent,  flexible,  and 
tough.  When  withdrawn  from  its  bed  and  examined,  it  appears  to 
present  three  coats — an  outer,  middle,  and  internal.  The  outer  is 
loose,  easily  detached,  somewhat  flocculent,  and  contains  more  or  less 
colouring  matter,  disposed  in  irregular  cells,  exactly  resembling  those 
figured  at  page  35,  from  the  outer  surface  of  the  choroid  coat  of  the 
eye.  We  have  not  found  a  true  epithelium  on  this  surface.  The 
middle  is  the  proper  coat,  and  seems  more  allied  to  cartilage  than 
any  other  tissue;  its  limits  are  well  marked,  it  is  transparent,  and 
exhibits  in  parts,  a  longitudinal  fibrillation;  treated  with  acetic  acid, 
it  presents  numerous  corpuscles  or  cell  nuclei.  Where  it  is  thinnest, 
it  has  a  near  resemblance  to  the  hyaloid  membrane  of  the  eye.  The 
internal  coat  is  composed  of  nucleated  particles,  closely  opposed,  and 
but  slightly  adherent;  the  nuclei  are  often  saucer-shaped,  and  when 
seen  edgeways  have  the  uncommon  appearance  of  a  crescent.  They 
easily  become  detached,  and  fall  into  the  endolymph.  Minute  arteries 
and  veins,  derived  chiefly  from  a  branch  of  the  basillar  accompanying 
the  auditory  nerve,  enter  the  vestibule  from  the  internal  meatus,  and 
ramify  on  the  exterior  of  the  membranous  labyrinth,  apparently  bathed 
in  the  perilymph.  A  beautiful  net- work  of  capillaries,  forcibly  remind- 
ing the  observer  of  that  belonging  to  the  retina,  is  spread  out  on 
the  outer  surface,  and  in  the  substance  of  the  proper  coat.  These 
vessels  have  the  simple  homogeneous  wall,  interspersed  here  and  there 
with  cell  nuclei,  that  characterizes  the  capillary  channels  in  many 


ORGANS  OF  THE  SENSES.  531 

other  situations.  There  is  an  abundant  net-work  of  capillaries  in  the 
interior  of  the  utriculus  and  sacculus,  about  the  terminal  distribution 
of  the  nerves,  which  evinces  the  activity  of  the  functions  of  these 
parts. 

"  The  membranous  labyrinth,  or  its  simple  representative,  the  audit- 
ory sac,  contains  in  all  animals,  either  solid  or  pulverulent  calcareous 
matter  in  connexion  with  the  termination  of  the  vestibular  nerves. 
This  has  been  called  by  Breschet  otolith  or  ear-stone,  when  solid,  as 
in  the  osseous  fishes,  and  otoconia  or  ear-powder,  when  in  the  form 
of  minute  crystalline  grains,  as  in  Mammalia,  birds,  and  reptiles ;  but 
the  former  term  may  be  conveniently  employed  to  designate  both 
varieties.  In  the  Mammalia,  including  man,  it  is  found  accumulated 
in  small  masses  about  the  termination  of  the  nerves,  both  in  the 
utriculus  and  sacculus,  and  we  have  found  it  also  sparingly  scattered 
in  the  cells  lining  the  ampullae  and  semi-circular  canals.  In  the 
vestibular  sacs  it  appears  to  be  entangled  in  a  mesh  of  very  delicate 
branched  fibrous  tissue,  in  connexion  with  the  wall,  and  it  is  most 
probably  held  in  place  by  cells  within  which,  according  to  Krieger,* 
its  particles  are  deposited.  It  has  a  regular  arrangement,  and  is  not 
free  to  change  its  place  in  the  endolymph.  Otolithes  consist  always 
of  carbonate  of  lime." 

Of  the  Vestibular  Nerves. — "  In  consequence  of  the  thickness  of 
the  wall  of  the  membranous  labyrinth  where  the  nerves  enter,  and 
the  presence  there  of  the  calcareous  and  fibrous  matter,  it  is  not  easy 
to  ascertain  with  certainty  the  precise  manner  in  which  the  nerves 
terminate.  In  the  utricule  and  saccule,  they  appear  to  spread  out 
from  one  another  as  they  enter,  and  then  to  pass,  some  to  mingle 
with  the  calcareous  powder,  others  to  radiate  for  a  small  extent  on 
the  inner  surface  of  the  wall  of  the  cavity,  where  they  come  into 
connexion  with  a  layer  of  dark  and  closely-set  nucleated  cells,  and 
presently  lose  their  white  substance.  We  have  seen  a  fibrous  film 
on  the  inner  surface  of  these  parts,  which  we  are  disposed  to  consider 
as  formed,  like  the  inner  surface  of  the  retina,  by  the  union  of  the 
axis-cylinders  of  the  nerve  tubes,  but  confirmatory  observations  are 
required.  Those  that  traverse  the  calcareous  clusters  have  appeared 
to  us,  in  the  most  lucid  views  we  have  succeeded  in  obtaining,  to 
terminate  by  free,  pointed  extremities,  without  losing  their  white  sub- 
stance.    In  the  frog  this  has  been  evident  enough. 

"  The  nervous  twigs  belonging  to  the  semi-circular  canals  do  not 
*  De  OtolUHs.    Berol,  1840. 


532  THE     SOLIDS. 

seem  to  advance  beyond  the  ampullae,  in  which  they  have  a  remark- 
able distribution — entering  them,  as  Steifensand  has  well  shown,  by  a 
transverse  or  forked  groove,  on  their  concave  side,  and  which  reaches 
about  a  third  round.  Within  this,  the  nerve  projects  so  as  to  form  a 
sort  of  transverse  bulge  within  the  ampulla.  Their  precise  termina- 
tion can  be  best  seen  in  the  osseous  fishes,  and  has  been  described 
by  Wagner  to  be  loop-like.  We  believe  we  have  seen  this  mode  of 
termination,  though  certainly  never  so  plainly  as  the  figure  given  by 
this  excellent  author  would  indicate;  and  we  may  add  that  we  have 
found  free  extremities  to  the  nerve  tubes,  as  well  as  loopings,  in  the 
ampullae  of  the  cod.  The  difficulty  in  these  cases  of  ascertaining 
the  exact  truth  arises  from  the  curves  formed  by  the  nerve  tubes  in 
proceeding  to  their  destination,  and  which  are  liable  to  be  mistaken 
for  terminal  loopings." 

Of  the  Auditory  Nerves. — "At  the  bottom  of  the  meatus,  the 
portio  mollis  divides  into  two  branches,  one  to  the  vestibule  and 
semi-circular  canals,  the  other  to  the  cochlea. 

"  The  vestibular  nerve  divides  into  three  branches ; — the  largest  is 
uppermost,  and  penetrates  the  depression  which  is  immediately  behind 
the  orifice  of  the  aqueduct  of  Fallopius  to  be  distributed  to  the 
utriculus,  and  to  the  ampullae  of  the  superior  vertical  and  horizontal 
semi-circular  canals.  The  second  branch  of  the  vestibular  nerve 
is  distributed  to  the  sacculus;  and  the  third  to  the  posterior  vertical 
semi-circular  canal. 

"The  cochlear  nerve  penetrates  the  funnel-shaped  depression  at 
the  bottom  of  the  auditory  canal,  and.  proceeds  from  it  through  the 
numerous  foramina,  by  which  its  wall  is  pierced  in  a  spiral  manner, 
to  the  lamina  spiralis  of  the  cochlea. 

"The  mode  of  distribution  of  these  nerves  has  been  already 
described. 

"The  labyrinth  receives  nerves  from  no  other  source  but  the  portio 
mollis,  unless  we  suppose  the  portio  intermedia  to  consist  of  filaments 
from  the  facial  which  accompany  the  ramifications  of  that  nerve  into 
that  part  of  the  ear." 


ORGANS  OF  THE  SENSES.  533 

EYE. 

[Little  need  be  said  with  regard  to  the  methods  of  studying  the  anatomy 
of  the  eye,  farther  than  the  directions  already  given.  The  sclerotic  and 
successive  lamina  of  the  cornea,  can  only  be  well  seen  on  careful  dissection  ; 
for  this  purpose,  fresh  eyes  are  necessary,  and  the  dissection  should  be 
made  under  water.  The  arrangement  and  size  of  the  tubes  of  the  cornea, 
may  be  seen  by  driving  mercury  or  air  into  a  slight  puncture.  A  thin 
section,  dried  and  opened  with  needles  under  water,  will  also  exhibit  them. 
Acetic  acid  is  a  valuable  assistant  in  minute  dissection  of  these  structures. 

The  vessels  of  the  choroid  membrane  and  of  the  ciliary  processes  are 
best  observed  after  injection;  a  foetal  subject  will  here  offer  the  best  chance 
of  success  when  the  injection  is  made  by  the  umbilical  vein.  To  examine 
the  tunica  Jacobi,  Quain  and  Sharpey  state  that  it  may  be  raised  from  the 
surface  of  the  retina  by  injecting  air  or  introducing  mercury  beneath  it, 
when  under  water.  The  retina  should  be  examined  in  the  freshest  possible 
state.  Wagner  recommends  white  rabbits  as  subjects;  the  pigmentary 
matter  of  the  choroid  coat  offering  no  obstacle  to  accurate  observation.  Dr. 
Hannover,  of  Copenhagen,  states  that  the  vitreous  body  is  best  studied  in  the 
eye  of  the  horse,  after  having  been  hardened  in  chromic  acid.  In  man,  he 
found  the  vitreous  humour  to  be  arranged,  as  it  were,  in  arched  slices  or 
wedges,  the  arches  turned  outwards,  and  the  angles  converging  towards  the 
axis  of  the  eye  like  the  wedges  of  an  orange.  If  the  sections  are  horizon, 
tal,  they  resemble  the  slices  of  an  orange  cut  from  pole  to  pole :  if  perpen- 
dicular, they  resemble  one  cut  at  right  angles  to  the  preceding  direction. 
This  arrangement  is  more  clearly  seen  in  infants  than  in  adults.  Dr. 
Hannover  was  unable  to  decide  whether  the  membrane  between  these 
segments  is  single  and  common  to  both,  or  whether  each  segment  is 
furnished  with  a  membrane  of  its  own.* 

Plate  LXXVIII.,  fig.  1,  The  terminal  vessels  in  the  cornea  of  the  eye 
of  the  pig. 
"  fig.  2,  Cornea  of  viper,  showing  its  vascularity. 

"  "  fig.  3,  Choroid  coat  of  foetal  eye. 

"  "  fig.  4,  Ciliary  processes  of  the  eye  of  an  adult.] 

*  Dublin  Quarterly  Journal,  May,  1848. 


APPENDIX. 


Pituitary    Gland. 

The  pituitary  body,  inasmuch  as  it  presents  the  usual  characteristics 
of  glandular  structures,  would  be  more  accurately  denominated  the 
pituitary  gland,  a  term  which  conveys  its  real  nature. 

The  pituitary  gland,  in  the  absence  of  an  excretory  duct — unless 
indeed  the  infundibular  process  attached  to  it  is  to  be  considered  as 
such — would  appear  to  be  allied  to  the  vascular  glands,  while  in  some 
other  respects  it  resembles  the  ganglia  of  the  sympathetic,  which  also 
are  glandular  organs. 

It  consists  of  two  lobes,  an  anterior  and  a  posterior,  which  differ 
from  each  other  in  size,  colour,  and  consistence;  the  former  is  con- 
siderably the  larger  of  the  two,  is  of  a  yellowish  gray  colour,  and  of 
much  firmness  and  density;  while  the  latter  is  gray  and  soft,  and 
scarcely  differs  in  consistence  from  the  gray  matter  of  the  cerebrum. 

As  the  two  lobes  differ  in  colour  and  consistence,  so  are  they  some- 
what different  in  structure  also;  the  anterior  or  denser  lobe  is  made 
up  of  numerous  granular  cells,  very  various  in  form  and  size,  and 
many  of  which  are  in  some  cases  of  very  considerable  dimensions; 
these  cells  lie  in  meshes  of  fibrous  tissue,  which  separate  and  parcel 
them  out,  each  of  the  larger  cells  occupying  separately  an  entire 
mesh.  (Plate  LXIX.  fig.  8.)  The  posterior  lobe  differs  from  the 
anterior  in  the  smaller  size  of  its  cells,  and  the  less  amount  of  fibrous 
tissue  which  enters  into  its  composition. 

The  pituitary  gland  is  connected  with  the  brain  by  means  of  the 
infundibulum,  the  small  extremity  of  which  is  attached  to  the  superior 
concave  surface  of  the  gland,  and  is  united  principally  to  the  posterior 
lobe,  which  it  also  resembles  in  structure,  containing  very  many 
granular  cells  in  its  parietes. 

This  gland  resembles  a  ganglion  of  the  sympathetic  in  the  large 
size  of  its  cells,  and  in  the  arrangement  of  its  fibrous  constituent ; 


536  APPENDIX. 

but  differs  from  it  in  the  irregular  form  of  the  cells,  and  in  the  absence, 
so  far  as  has  been  yet  ascertained,  of  tubular  nerve  fibres. 

Pineal  Gland. 

Notwithstanding  the  interest  which  exists  in  the  minds  of  most 
persons  in  reference  to  this  body,  and  which  has  arisen  in  conse- 
quence of  the  strange  physiological  speculations  of  which  it  has  been 
the  subject,  its  structure  yet  does  not  appear  to  have  been  examined 
with  that  amount  of  care  which  has  now  been  bestowed  upon  most 
of  the  other  organs  which  enter  into  the  constitution  of  the  human 
fabric;  not,  however,  that  its  organization  is  uninteresting  or  difficult 
to  be  understood ;  for  this,  while  it  is  complex  and  singular,  yet  admits 
of  easy  determination. 

The  chief  bulk  of  the  pineal  gland,  is  made  up  of  innumerable 
minute  granular  cells,  which,  when  carefully  examined  in  a  perfectly 
fresh  subject,  are  seen  to  be  of  the  caudate  form,  the  rays  of  the  cells 
being  exceedingly  delicate  and  slender,  and  apt,  therefore,  to  be 
entirely  overlooked. 

Imbedded  in  this  cellular  matrix,  and,  for  the  most  part,  collected  in 
the  centre  of  the  organ,  there  may  be  noticed  numerous  particles  of 
stony  hardness  of  various  sizes,  and  mostly  of  a  rounded  form,  and 
the  larger  of  which  are  plainly  visible  to  the  naked  eye.  Of  these 
bodies,  I  have  never  encountered  any  satisfactory  description ;  they 
are  not,  as  generally  considered,  mere  inorganic  and  earthy  particles, 
but  structures  of  a  definite  and  complex  organization,  constituting  an 
essential  element  in  the  composition  of  the  pineal  gland.  When 
viewed  with  the  half  or  quarter-inch  object-glass,  the  larger  of  these 
bear  much  resemblance  to  masses  of  fat,  each  being  composed  of 
numerous  distinct  and  aggregated  lesser  pieces,  or  particles  which 
reflect  light  strongly,  and  it  is  in  this  circumstance,  as  well  as  in  their 
large  size,  that  the  resemblance  borne  by  these  bodies  to  masses  of 
fat  consists.     (Plate  LXIX.  jig.  7.) 

In  the  natural  condition,  these  bodies  are  hard  and  brittle;  after, 
however,  the  application  of  dilute  nitric  acid,  they  become  soft,  the 
earthy  matter  being  dissolved  away,  and  nothing  remaining  but  their 
animal  constituent ;  this,  if  the  acid  employed  has  not  been  too  strong, 
still  retains,  to  a  great  extent,  the  size,  form,  and  appearance  of  these 
bodies,  previous  to  its  action,  and  will  now  readily  be  seen  to  exhibit 
a  cellular  structure,  a  cell  corresponding  to  each  of  the  bright  con- 
stituent pieces  above  described.     If,  however,  the  acid  employed  be 


APPENDIX.  537 

somewhat  stronger,  these  bodies  undergo  a  singular  change  in  form 
and  appearance,  the  cellated  spaces  become  almost  lost  to  view,  and 
these  compound  structures  assume  the  characters  of  large  and  spher- 
ical cells  exhibiting  numerous  concentric  lamellae.  The  earthy  matter, 
then,  is  contained  in  these  cells  or  cellated  spaces;  the  acid  dissolves 
this  away,  and  the  entire  body  becomes  so  soft,  as  to  admit  readily  of 
being  torn  to  pieces  with  needles;  in  this  state,  its  structure  may  be 
easily  determined,  and  is  seen  to  consist  of  membranous  elastic  tissue. 

These  bodies  originate  in  exceedingly  small  and  bright  circular 
discs,  which,  when  seen  with  the  quarter-inch  object-glass,  are  less  in 
size  than  the  head  of  a  pin;  in  these  appear  first,  one,  and,  afterwards, 
other  divisions,  indicating  the  compound  and  cellular  character,  which 
they  ultimately  more  completely  exhibit. 

The  earthy  matter  entering  into  their  composition  consists  of  phos- 
phate of  lime,  a  small  portion  of  phosphate  of  magnesia,  and  a  trace 
of  carbonate  of  lime. 

Minute  sandy  particles  have  been  described  connected  with  the 
choroid  plexuses,  and  that  portion  of  the  velum  inter-positum  which 
invests  the  pineal  gland ;  whether  these  bodies  are  of  the  same  nature 
as  those  occurring  in  the  gland  itself,  I  am  unable  to  say,  not  having 
myself  detected  them  in  either  of  the  above  situations. 

These  bodies,  which  are  almost  peculiar  to  the  human  subject,  are 
stated  not  to  occur  in  the  pineal  gland,  until  after  the  age  of  seven 
years. 

In  addition  to  the  above  described  essential  elements  of  every  fully 
formed  human  pineal  gland,  I  encountered  on  one  occasion  two  large 
round  cells  or  bodies,  containing  dark  nuclei  of  a  compound  charac- 
ter; these  appeared  to  be  some  modification  of  the  sabulous  bodies 
already  described. 

The  pineal  gland  is  copiously  supplied  with  blood-vessels,  is  trav- 
ersed sparingly  with  delicate  nerve  tubules,  and  contains  a  small 
quantity  of  an  exceedingly  slender  form  of  fibrous  tissue,  which 
possibly  proceeds  from  the  caudate  cells  already  noticed. 

The  Pia  Mater. 

The  pia  mater,  the  vascular  membrane  of  the  brain,  is  composed 
of  fibrous  tissue  and  blood-vessels ;  over  the  surface  of  the  brain  and 
its  convolutions,  this  membrane  is  delicate  and  highly  vascular,  while 
over  the  spinal  marrow,  it  is  thicker  and  less  freely  supplied  with 
vessels. 


533  APPENDIX. 

In  the  ventricles,  this  membrane  forms  the  choroid  plexuses  and 
velum  inter-positum ;  in  the  former,  it  is  thrown  up  into  numerous 
processes  or  villi,  each  of  which  is  furnished  with  a  large  looped 
blood-vessel,  and  its  outer  surface,  like  the  villi  of  the  intestines,  is 
clad  with  a  very  evident  epithelium.     (Plate  LXIX.  fig.  9.) 

This  epithelium,  according  to  many  observers,  -is  of  the  ciliated 
kind;  the  cells  composing  it,  are  polygonal  somewhat  flattened,  and, 
as  Henle*  long  since  noticed,  furnished  at  their  angles  with  spinous 
processes;  these  are  only  to  be  seen  in  perfectly  fresh  subjects,  and  it 
is  probable  that  in  some  cases,  they  have  been  mistaken  for  cilia;  not, 
however,  since  the  fact  has  been  attested  by  several  witnesses,  that  I 
would  deny  the  existence  of  ciliary  processes  on  the  cells  of  this 
epithelium. 

.  The  Pacchionian  Glands. 

The  Pacchionian  Glands  are  found  among  the  vessels  of  the  pia 
mater  on  the  edges  of  the  cerebral  hemispheres,  and  are  described  as 
granulations  composed  of  an  albuminous  material;  they  push  before 
them  the  arachnoid  membrane,  project  into  the  longitudinal  sinus, 
and,  in  cases,  even  occasion  absorption  of  the  parietal  bones,  lying 
imbedded  in  little  pits  or  recesses.  They  are  stated  not  to  occur  in 
early  life,  and  they  are  frequently  absent  in  the  adult. 

I  have  encountered  on  the  surface  of  different  portions  of  the  pia 
mater,  usually  near  to  the  sulci  of  the  convolutions,  little  masses  or 
bodies  of  two  forms,  apparently  very  distinct ;  in  the  first,  these  were 
opaque  and  whitish,  and  consisted  of  a  capsule  of  fibrous  tissue, 
enclosing  a  number  of  minute  granular  cells;  in  the  second,  the 
masses  appeared  to  lie  free  among  the  vessels  of  the  pia  mater,  and 
each  broke  up  readily  on  being  touched  into  several  other  smaller 
granulations  of  the  same  character:  these,  examined  with  the  micro- 
scope, were  seen  to  be  made  up  of  numerous  dark-looking  bodies, 
very  irregular  in  form  and  size,  and  which  appeared  to  be  of  a  fatty 
nature. 

Observations  on  the  Development  of  the  Fat  Vesicle.-f 

"When  the  difficulty  of  determining  the  exact  structure  of  the  fat 
vesicle  is  considered — a  difficulty  arising  from  the  extreme  tenuity 
of  its  cell- wall,  and  the  opacity  of  its  contents — it  is  scarcely  surpris- 

*  Anat.  Gen.  t.  i.  p.  233. 

f  By  the  Author. — Lancet,  January  20th,  1849. 


APPENDIX.  539 

ing  that  we  should  yet  be  without  any  consistent  account  of  the 
modes  of  development  and  growth  of  the  fat  vesicle. 

"This  hiatus  in  the  structural  history  of  that  peculiar  animal  tissue, 
fat,  the  present  brief  remarks  are  intended  in  some  measure  to  fill  up. 

"When  the  little  fatty  masses  which  are  met  with  so  abundantly  in 
the  neck,  in  the  neighbourhood  of  the  thyroid  and  thymus  glands,  as 
also  in  some  other  situations  in  a  foetus  nearly  or  quite  arrived  at 
maturity,  are  examined,  it  will  be  observed,  by  the  use  of  a  lens  only, 
that  these  masses  are  each  composed  of  a  number  of  distinct  and 
opaque  bodies  of  various  sizes,  presenting  a  smooth  outline,  having  a 
more  or  less  rounded  or  oval  form,  and  held  loosely  together  by  fibro- 
cellular  tissue,  the  extension  of  which  forms  the  envelope  which 
invests  each  of  these  bodies.  It  will  also  be  further  noticed  that  each 
mass  of  fat  is  supplied  with  one  or  more  blood-vessels,  and  that  these 
break  up  into  numerous  lesser  branches,  one  of  which  goes  to  each 
of  the  previously-described  bodies,  being  conveyed  to  it  by  the  con- 
necting fibrous  tissue;  and  that,  having  reached  this  body,  it  undergoes 
a  further  sub-division,  the  branches  extending  over  its  entire  surface. 

"In  continuation  of  these  observations,  it  will  be  remarked,  that 
each  of  these  peculiar  bodies  bears  a  close  resemblance  in  its  general 
aspect,  to  a  lobe  of  a  sebaceous  gland — a  resemblance,  which,  as  will 
be  seen  almost  immediately,  extends  even  to  its  internal  structure. 

"If  a  number  of  these  bodies  be  torn  into  fragments  with  fine 
needles,  and  be  examined  with  a  half  or  quarter-inch  object-glass,  it 
will  be  observed  that  the  cavities  of  some  of  them  are  filled  with 
cells  of  a  large  size,  and  which  again  are  occupied  with  numerous 
globules  of  various  dimensions,  presenting  many  of  the  characters 
of  oil  globules,  but  being  of  greater  consistence.  (Plate  LXIX. 
Jig.  10.)  These  cells,  save  by  their  somewhat  larger  size,  it  is  impos- 
sible to  distinguish  from  the  perfect  cells  of  sebaceous  glands;  so 
complete  indeed  is  this  resemblance,  that  at  first  sight  I  did  not 
hesitate  to  regard  them  as  belonging  to  some  sebaceous  gland,  and 
which  I  was  much  astonished  to  encounter  in  such  a  situation. 
Others  of  these  peculiar  bodies,  which  may  be  termed  'fat  cysts,' 
contain  a  mixture,  in  variable  proportions,  of  these  compound  cells  and 
of  free  globules,  which,  however,  it  is  to  be  observed,  are  generally  of 
larger  size  than  those  contained  within  the  compound  or  parent  cells. 
Lastly,  others  of  these  bodies  enclose  no  compound  cells,  but  are  filled 
with  globules  of  still  larger  size.     (Plate  h~X.lX.Jig  11.) 

"Now,  the  curious  part  of  this  history  is,  that  it  is  these  globules 


540  APPENDIX. 

which  go  on  increasing  in  size,  and,  bursting  the  envelopes  which 
contain  them,  ultimately  become  what  are  ordinarily  regarded  as  the 
true  fat  vesicles. 

"In  the  article  Fat,  in  an  early  number  of  the  'Microscopic 
Anatomy,'  I  noticed  the  fact,  that  the  fat  vesicles  of  children  are  not 
so  large  as  those  of  the  adult;  this  fact  it  then  appeared  to  me  had  an 
evident  relation  to  the  growth  of  the  fat  vesicle,  and  it  suggested  the 
idea  that  the  fat  corpuscle  was  of  very  slow  growth,  not  attaining  its 
full  dimensions  until  near  the  adult  age ;  and  that  it  was  permanent  in 
its  character,  enduring  throughout  life.  This  idea  gathers  increased 
weight,  and,  indeed  its  correctness  is  rendered  almost  certain,  by 
the  additional  observations  just  cited  on  the  development  and  growth 
of  the  fat  vesicle. 

"It  would  appear,  therefore,  taking  into  consideration  all  the  fore- 
going particulars,  that  the  principal  development  of  fat  vesicles  takes 
place  in  the  advanced  fetus,  and  in  the  early  years  of  life  (for  I  now 
remember  having  met  with  'fat  cysts'  in  the  great  omentum  of 
children  of  five  and  six  years  of  age,  although  at  the  time  of  observ- 
ing them  I  did  not  know  their  nature  and  meaning),  that  what  are 
usually  regarded  as  the  true  fat  vesicles  or  cells,  are  first  contained  in 
parent  cells,  and  lastly,  that  they  are  slow  in  their  growth,  and 
persistent  throughout  life. 

"I  infer  also  further,  from  the  foregoing  facts,  that  the  ordinary  fat 
vesicles  are  incapable  of  acting  as  parent  cells  and  of  reproducing 
their  like;  an  inference  which  might  be  fairly  entertained  on  other 
grounds,  viz:  the  difficulty,  not  to  say  impossibility,  of  detecting 
nuclei  in  them,  and  the  absence  of  those  granules  among  their  contents 
which  are  so  characteristic  of  true  cells,  and  which  there  is  so  much 
reason  to  believe  are  the  real  germs  of  the  future  generations  of  cells. 

"From  comparative  observations  it  would  appear  that  the  develop- 
ment and  growth  of  fat  proceed  at  different  rates  in  different  localities 
of  the  same  body,  it  being  more  advanced  in  one  situation  than  in 
another;  and  also  in  the  same  parts  in  different  children  of  the  same 
age;  so  that  an  exactly  similar  condition  of  things  to  that  which  I  have 
described  as  existing  in  the  masses  of  fat  which  occur  in  the  region 
of  the  neck  in  the  mature  fetus,  must  not  in  all  cases  be  looked  for. 

"  The  structural  resemblance  which  I  have  shown  to  exist  between 
fat  cells  in  an  early  condition  of  their  development,  and  the  cells  of 
sebaceous  glands  is  most  interesting,  the  latter  appearing  to  be,  in  fact, 
simply  fat  in  a  rudimentary  and  imperfect  state  of  its  development." 


APPENDIX.  54 1 

On  the  Structure  and  Formation  of  the  Nails. 

Since  the  publication  of  the  article  contained  in  this  work  on  the 
structure  of  nail,  some  further  observations  by  Mr.  Raine}r,  on  the 
same  subject,  have  appeared;  the  more  important  of  these  are  con- 
tained in  the  following  extracts  :* 

"The  object  of  this  paper  is  to  show  that  the  nails  consist  of  at  least  two  distinct 
structures;  one  proper  to  them,  the  horny  structure,  and  the  other  the  cuticular  one; 
and  also,  that  their  matrix  possesses  one  set  of  vessels  expressly  for  the  secretion 
of  the  horny  part  of  the  nail,  and  another  set  for  the  formation  of  the  cuticular  por- 
tion; and  that  besides  these,  there  are  other  vessels,  differing  in  their  characters  and 
arrangement  from  the  preceding,  and  probably  intended  to  furnish  a  material,  inter- 
mediate in  some  of  its  properties  between  horn  and  cuticle,  and  destined  to  blend 
these  together,  and  thus  to  preserve  their  union  during  the  growth  and  protrusion 
of  the  nails.  However  far  this  idea  may  be  correct,  the  anatomical  fact  of  there 
being  these  three  different  arrangements  of  vessels  is  indisputable." 

Structure  of  the  Nails. 

"If  a  thin  vertical  section  be  made  length  ways  through  a  finger-nail  from  its  poste- 
rior to  its  anterior  or  free  margin,  the  external  or  dorsal  surface  of  that  portion  of  it 
which  was  lodged  in  the  groove  between  the  matrix  and  the  semi-lunar  fold  of  skin 
projecting  from  the  dorsum  of  the  finger,  is  seen  covered  by  a  thin  layer  of  cuticle, 
which  extends  backwards  as  far  as  its  posterior  border,  which  is  generally  jagged  and 
uneven,  and  forwards  upon  its  dorsum.  This  portion  of  cuticle  is  immediately  con- 
tinuous with  that  overhanging  the  root  of  the  nail,  and  although  it  is  not  inseparably 
blended  with  its  horny  substance,  yet  it  is  sufficiently  adherent  to  be  carried  forward 
with  it  during  its  growth,  and  to  remain  intimately  attached  to  its  dorsal  surface  until 
it  is  worn  off  by  friction  or  some  other  mechanical  cause.  The  palmar  surface,  near 
to  its  free  border,  is  also  seen  covered  by  cuticle,  which  in  like  manner  divides  into 
two  parts,  the  one  becoming  continuous  with  the  cuticle  covering  the  end  of  the 
finger;  the  other  passing  backwards  along  the  palmar  surface  of  the  nail  as  far  as 
the  lunula,  where  it  imperceptibly  terminates.  This  portion  of  cuticle  gradually 
diminishes  in  thickness  as  it  extends  backwards,  and  is  more  intimately  connected 
with  the  horny  part  of  the  nail  than  was  the  cuticle  on  its  dorsal  surface.  Between 
these  layers  of  cuticle  the  proper  or  horny  matter  of  the  nail  can  be  distinguished, 
presenting  fine,  nearly  parallel,  and  generally  semi-elliptical  lines,  with  their  con- 
cavity looking  in  different  directions  in  different  parts  of  the  same  section,  and  also  a 
multitude  of  darkish-looking  corpuscles,  when  viewed  by  transmitted  light,  of  various 
forms  and  sizes.  These  compose  the  substance  of  the  horn  of  the  nail,  and  the  lines 
are  the  cut  edges  of  the  laminas  of  which  it  is  made  up.  The  horny  part  of  the  nail 
does  not  increase  in  thickness  after  it  has  extended  beyond  the  lunula,  the  apparent 

*  "On  the  Structure  and  Formation  of  the  Nails  of  the  Fingers  and  Toes."  By  G. 
Rainey,  Esq.,  M.  R.  C.L.— Transactions  of  the  Microscopical  Society,  March,  1849. 


542  APPENDIX. 

increase  of  the  nail  anterior  to  this  point  being  derived  from  the  cuticle  formed  upon 
the  anterior  part  of  the  matrix." 

The  Matrix  of  the  Nail. 

"A  mere  inspection,  even  in  the  living  subject,  of  the  parts  situated  beneath  the 
nail,  is,  in  consequence  of  its  transparency,  sufficient  to  give  a  general  idea  of  the 
relative  vascularity  of  the  various  parts  of  its  matrix  The  upper  part  of  the  matrix 
is  seen  to  present  a  pale,  semi-lunar  space,  called  the  lunula.  The  greater  part  of  the 
lunula  is  concealed  by  the  semi-lunar  fold  of  integument  which  projects  over  it;  but 
extending  a  little  below  this  fold,  the  lower  portion  of  the  lunula  is  visible,  presenting 
a  curved  border,  with  its  convexity  looking  downwards.  Immediately  below  the 
lunula,  and  circumscribing  its  inferior  limit,  the  matrix  has  a  reddish  colour,  which 
gradually  becomes  fainter  towards  the  free  margin  of  the  nail,  but  which  deepens 
considerably  where  the  nail  becomes  detached  from  the  integument. 

"When  the  matrix  is  fully  injected  and  the  nail  removed,  the  part  corresponding 
to  the  lunula  presents  several  rows  of  convoluted  capillaries :  the  individual  convo- 
lutions have  different  degrees  of  complexity,  from  a  simple  loop  (a  little  twisted 
round  itself,)  to  a  complex  tuft  of  vessels.  These  rows  have  their  direction  from 
above  to  below ;  they  are  all  slightly  curved,  being  concave  towards  the  median  line 
of  each  nail,  and  the  most  external  ones  are  nearly  parallel  with  its  lateral  margins. 
These,  being  the  vessels  which  secrete  the  horny  part  of  the  nail,  may  be  called  the 
horn-vessels.  Superiorly  these  vessels  are  separated  from  the  rich  plexus  on  the  fold 
of  integument  which  overhangs  the  nail,  by  a  fibrous  and  almost  non-vascular  groove, 
in  which  the  free  border  of  the  nail  was  lodged,  and  where  the  cuticle  covering  its 
root  terminates.  A  few  vessels,  however,  pass  across  this  groove  from  the  horn- 
vessels  to  the  plexus  just  mentioned.  Inferiorly  the  horn- vessels  communicate  with 
quite  a  different  arrangement  of  capillaries,  which  run  in  a  more  straight  course,  and 
are  much  more  crowded  together  than  the  horn-vessels.  'These  vessels  run  nearly 
parallel  with  one  another,  in  a  direction  from  behind  forwards,  and  being  very 
near  together,  render  this  the  most  vascular  part  of  the  matrix,  and  produce  that 
redness  immediately  below  the  lunula  upon  which  the  form  and  degree  of  dis- 
tinctness of  its  lower  border  is  dependent.  Just  below  these  vessels  the  surface  of 
the  matrix  begins  to  be  raised  into  numerous  plications  or  folds,  passing  directly  for- 
wards, and  increasing  in  depth  as  they  approach  the  free  extremity  of  the  nail,  where 
they  become  continuous  with  the  raised  lines  observable  on  the  ends  of  the  fingers. 
These  plicae  consist  each  of  a  fold  of  basement  membrane,  enclosing  a  series  of  loops 
of  vessels.  At  first  these  loops  are  small  and  simple,  but  they  become  larger  and 
more  complex,  as  they  advance  towards  the  end  of  the  finger,  where  they  are  con- 
tinued from  the  ridges  of  the  matrix  of  the  nail  into  those  of  the  skin  ofthe  finger, 
in  which  they  are  generally  very -complex.  When  the  nails  are  in  situ,  these  ridges 
are  received  into  corresponding  grooves  in  their  inferior  surface.  Near  the  part  of  the 
matrix  where  the  plicae  commence,  several  distinct  circular  or  oval  openings  are 
sometimes  seen  passing  for  some  depth  beyond  the  surface,  and  appearing  like  fol- 
licles or  lacunae.  These  are  frequently  closed  by  the  opposition  of  the  adjacent 
plicae,  and  thus  their  presence  is  rendered  doubtful,  but  they  can  be  seen  very  dis- 
tinctly either  when  some  of  the  material  which  they  contain  has  been  recently  removed, 
or  still  remains  within  them  in  the  form  of  whitish,  globular  masses.    The  situation 


APPENDIX.  543 

of  these  lacunae,  where  the  openings  themselves  are  not  apparent,  can  be  dis- 
tinguished by  the  plexus  of  capillaries  in  their  vicinity,  in  the  areola;  of  which  their 
openings  are  situated." 

On  the  Ganglionic  Character  of  the  Arachnoid  Membrane. 

The  following  extracts  contain  the  more  important  portions  of  Mr. 
Rainey's  observations  "on  the  Ganglionic  Character  of  the  Arach- 
noid Membrane  of  the  Brain  and  Spinal  Marrow : "  *    • 

"  The  first  idea  which  suggested  to  me  the  resemblance  of  the  arachnoid  to  the 
sympathetic,  was  from  the  examination  of  a  piece  of  the  former  taken  from  the  infe- 
rior and  lateral  part  of  the  medulla  oblongata,  when  I  observed,  at  the  meeting  of 
two  of  the  chords  situated  between  the  arachnoid  and  pia  mater  (called  by  Magendie 
'Tissu  Cellulo-vasculaire  sub-Arachnoid'),  a  triangular  body  of  the  form  and  general 
appearance  of  the  ganglion,  very  similar  to  such  as  I  had  seen  in  small  animals. 

"  This  resemblance  appeared  more  striking  on  observing  a  branch  going  from  the 
chord  connected  with  this  body  to  the  arachnoid  membrane,  along  which  it  ran  for  a 
considerable  distance,  dividing  and  sub-dividing  in  its  course,  in  the  manner  of  a 
nerve ;  the  successive  sub-divisions  becoming  more  and  more  minute,  and  at  the  same 
time  interlacing  and  enclosing  small  areola;  filled  with  corpuscular  matter.  These 
corpuscles  were  so  blended  with  the  ultimate  filaments  of  this  chord  as  to  render 
indistinct  their  exact  mode,  of  termination. 

"  Such  was  the  connexion  of  one  extremity  of  one  of  these  chords.  The  next 
point  to  be  determined  was  the  structure  to  which  the  other  extremity  of  the  same 
chord  had  been  attached.  As,  in  this  case,  it  had  been  separated  from  its  connexion, 
this  could  only  be  ascertained  by  examining  similar  chords  in  other  portions  of  mem- 
brane. This  examination  being  made,  I  found  that  the  end  in  question  terminated 
either  on  an  artery  or  on  a  cerebro-spinal  nerve.  In  the  former  case,  a  chord,  as  soon 
as  it  comes  in  contact  with  an  artery,  divides  into  branches  which  ramify  upon  it,  and 
run  along  its  external  coat,  just  as,  to  all  appearance,  the  branches  of  the  solar 
plexus  do  on  the  small  arteries  supplying  the  viscera  in  the  abdomen.  If  the  cerebral 
artery  be  rather  large,  and  situated  between  the  arachnoid  and  pia  mater,  some  of  the 
branches  going  from  a  chord  form  upon  it  a  plexus,  and  others  proceed  onwards  to 
the  vessels  of  the  pia  mater. 

"  In  some  instances  a  chord  passes  from  an  artery  to  the  arachnoid  without  dividing 
in  its  course,  as  just  described ;  but  more  frequently,  on  approaching  tho  latter, 
it  sends  off  three  or  four  large  branches,  which  pass  to  different  parts  of  the  mem- 
brane, and  ramify  in  it,  as  before  explained;  however,  sometimes  one  of  these 
branches  either  itself  expands  into  a  large  dense  plexus,  or  joins  other  branches  to 
form  one,  from  which  plexus  two,  three,  or  more  chords  pass  into  the  substance  of 
the  arachnoid.  The  shape  of  these  plexuses  is  either  square  or  triangular,  according 
to  the  number  of  branches  which  join  them,  and  the  number  they  give  off.  Besides 
consisting  of  interlacing  fibres,  they  also  contain  corpuscular  matter. 

"  The  arachnoidal  extremity  of  some  of  the  chords  connecting  the  vessels  with  the 

*  Medico- Chirurgical  Transactions,  1846. 


544  APPENDIX. 

arachnoid  of  the  cauda  equina  expands,  close  to  the  membrane,  into  a  large  oblong 
and  rather  oval  bulb,  the  axis  of  which  is  occupied  by  a  continuation  of  the  chord, 
extremely  convoluted,  and  bent  upon  itself;  while,  inferiorly,  its  fibres  are  blended 
with  those  of  the  membrane. 

"  The  chords  which  pass  from  the  vessels  of  the  pia  mater,  at  the  upper  portion  of 
the  brain  to  the  arachnoid,  terminate  in  the  latter  by  fibres  having  a  stellate  arrange- 
ment. There  are  also  some  large  triangular  plexuses  like  those  at  the  base  of  the 
brain,  from  which  branches  descend  between  the  convolutions  to  the  vessels  within 
the  sulci. 

"  In  the  lower  animals,  as  in  the  sheep,  in  which  the  cerebral  convolutions  are 
small,  the  stellate  fibres  are  the  best  seen.  They  can  even  be  distinguished  by  the 
naked  eye,  appearing  like  minute  opaque  points.  At  their  centre,  the  fibres  of  which 
they  are  composed,  seem  to  be  blended  into  an  irregular  confused  mass,  from  which 
other  fibres  radiate,  and  lose  themselves  in  the  cerebral  surface  of  the  arachnoid. 
Some  fibres  go  from  one  stellate  body  to  another,  and  others  can  be  traced  into  the 
coats  of  the  vessels :  these  latter  are  by  no  means  numerous.  Branches  also  descend 
(still  having  somewhat  the  stellate  disposition)  between  the  convolutions  to  the 
deep-seated  vessels;  these  filaments  are  much  more  numerous  upon  some  vessels 
than  upon  others,  and  they  do  not  appear  to  extend  so  far  as  the  capillaries,  no  fibres 
of  any  kind  being  visible  upon  this  system  of  vessels. 

"  It  appears,  from  what  has  been  stated,  that  the  disposition  of  the  ramifying  fila- 
ments of  the  arachnoidal  chords,  and  the  form  and  size  of  the  gangliform  plexuses 
connected  with  them,  bear  some  proportion  to  the  number  and  size  of  the  vessels  in 
their  vicinity.  Hence,  about  the  base  of  the  brain,  where  the  branches  of  the  arteries 
are  large,  the  plexuses  are  also  large,  and  of  an  irregular  shape,  while  oh  its  upper 
surface,  where  the  vessels  are  comparatively  small,  and  more  equal  in  size,  and  have 
a  more  uniform  distribution,  the  plexuses  are  also  smaller,  more  numerous,  and  more 
regular  in  their  shape  and  volume. 

"  Besides  the  plexuses  situated  in  the  course  of  the  chords  of  the  arachnoid,  there 
are  others  which  are  more  intimately  connected  with  its  cerebral  surface,  and  which, 
in  some  situations,  appear  to  compose  the  entire  thickness  of  the  membrane. 

"  In  these  plexuses,  the  filaments  interlace  very  much  in  the  same  manner  as  the 
nerves  do  in  the  plexuses  of  the  cerebro-spinal  and  sympathetic  systems.  A  chord, 
for  instance,  when  traced  into  one  of  them,  will  be  observed  to  break  up  into  its  com- 
ponent filaments,  the  adjoining  bundles  of  which  interlace,  yielding  to  one  another 
one  or  more  bundles,  and  the  chords  which  emerge  from  the  plexuses  deriving  their 
component  filaments  from  different  bundles:  these  bundles  and  their  component 
threads,  during  their  interlacing,  will  be  seen  to  preserve  their  individuality. 

"  When  a  chord  going  from  the  arachnoid,  terminates  on  a  cerebral  nerve,  it  divides 
in  the  same  manner  as  an  artery,  some  filaments  ascending  and  others  descending 
along  with  the  nerve  tubules.  In  some  instances  this  extremity  terminates  in  a  sort 
of  membranous  expansion,  which  encloses  several  nerve  tubules." 

Mr.  Rainey,  in  the  next  place,  enters  upon  the  consideration  of  the  nature  of  the 
above-described  apparatus  of  ramifying  chords  and  plexuses,  and  arrives  at  the  con- 
elusion,  derived  from  their  relations  and  intimate  structure,  that  they  are  composed 
essentially  of  gelatinous  or  sympathetic  nerve  filaments. 


APPENDIX.  015 

"In  the  chords  of  the  arachnoid  (he  writes)  I  could  distinguish  three  different 
kinds  of  filaments,  all  which  exist  in  the  branches  of  the  sympathetic. 

"One  species,  generally  considered  the  most  characteristic,  is  the  nuclear  fibre 
described  by  Henle ;  it  is  a  flat,  clear  fibre,  with  oval,  nearly  equi-distant  nuclei,  and 
each  having  its  long  axis  corresponding  to  that  of  the  fibre.  I  have  found  these 
fibres  in  the  arachnoid,  but  they  are  very  rare.  I  have  seen  such  going  from  the 
arachnoid  to  the  coat  of  the  internal  carotid,  the  trunks  being  blended  with  the  mem- 
brane, and  the  branches  connected  with  the  artery.  I  also  found,  that  as  the  fibres 
branch  off  from  these  trunks,  and  intermix  with  others,  they  lost  their  nuclei,  became 
more  pale  and  clear,  and  differed  in  no  respect  whatever  from  the  other  fibres  of  the 
membrane.  Besides,  I  have  seen  these  fibres  in  other  parts  of  the  membrane,  and 
they  exist  chiefly  on  the  exterior  of  the  larger  chords.  This  species  of  fibre  I  have 
also  found  to  be  very  uncommon  in  the  smaller  branches  of  the  nerves  confessedly 
sympathetic,  especially  in  those  most  remote  from  the  ganglia  and  larger  trunks. 
The  next  kind  of  fibre  is  one  consisting  of  bundles,  for  the  most  part  rather  smaller 
than  nerve  tubules,  of  very  minute  wavy  filaments,  intermixed  with  small  particles  of 
granular  matter,  having  no  definite  form,  size,  or  position  in  respect  to  the  filaments. 
Some  of  the  chords  of  the  arachnoid  are  made  up  entirely  of  fibres  of  this  description; 
in  others  they  exist  chiefly  on  their  surface,  being  most  abundant  near  their  attach- 
ment to  the  arachnoid,  upon  which  they  are  continued.  This  kind  of  fibre  exists 
abundantly  in  all  the  branches  of  the  nerves  undoubtedly  sympathetic;  and  also, 
more  or  less,  in  those  connected  with  the  ganglia.  The  third  kind  of  fibre  occurs  in 
the  form  of  roundish,  though  sometimes  flat  chords,  composed  of  extremely  minute 
wavy  filaments,  either  collected  or  not  into  bundles,  but  apparently  interwoven  some- 
what together,  so  that,  generally,  a  filament  of  only  an  inconsiderable  length  will 
admit  of  being  detached  mechanically  from  the  rest,  and,  when  thus  separated,  its 
breadth  is  very  unequal,  and  its  contour  ill-defined.  These  filaments  are  often  totally 
destitute  of  granular  matter. 

"This  last  species  of  fibre  is  very  common  among  the  chords  composing  the  plex- 
uses of  the  arachnoid ;  it  is  also  sometimes  situated  in  the  centre  of  the  larger  ones, 
surrounded  by  the  second  species  of  fibre;  this  can  be  detached  mechanically,  and 
exhibited  separately  under  the  microscope. 

"In  the  nerves  obviously  sympathetic,  this  kind  of  fibre  exists  in  considerable 
abundance  in  those  branches  of  the  solar  and  other  plexuses  which  are  most  remote 
from  the  ganglia. 

"Thus  far  my  observations  have  been  confined  to  the  structure  of  the  fibres  of  the 
arachnoid,  and  their  supposed  use.  I  will  now  consider  the  corpuscular  or  ganglionic 
part  of  this  membrane.  Some  of  the  plexuses  on  its  cerebral  surface  have  the  inter- 
stices formed  by  their  interlacing  fibres,  completely  filled  up  with  small  roundish 
corpuscles,  about  the  size  of  blood-discs ;  while,  in  others,  these  fibres  are  covered 
with  irregularly-oval  masses  of  them.  On  this  surface,  also,  in  various  situations, 
there  are  well-defined  round  or  oval  bodies,  having  in  their  centre  a  granular  nucleus 
surrounded  by  fibrous  tissue,  intermixed  with  more  or  less  corpuscular  matter. 
Some  of  these  bodies  are  connected  to  the  fibres  of  the  arachnoid  by  a  yery  fine 
thread,  others  are  situated  at  the  conflux  of  two  or  more  fibrous  chords,  and  their 
diameter  varies  from  that  of  two  to  seven  blood  corpuscles.  They  are  generally 
solitary  and  not  numerous;  but  as  they  have  been  present  iii  the  arachnoid  of  every 
human  subject  which  I  have  examined  (a  number  exceeding  twenty),  they  cannot  be 

35      ' 


546  APPENDIX 

regarded  as  accidental  or  adventitious.  At  present  I  cannot  decide  as  to  their  nature 
or  office,  not  having  seen  any  thing  which  they  exactly  resemble  in  other  parts  of  the 
body;  at  any  rate,  they  look  more  like  small  ganglia  than  any  thing  else  I  have  seen. 
"  Besides  these  corpuscles,  which,  as  before  stated,  exist  on  the  cerebral  surface  of 
the  arachnoid,  I  have  met  with  some  of  a  very  different  character,  situated  in  its  sub- 
stance, though  nearer  to  the  cranial  than  to  the  cerebral  surface.  The  most  ordinary 
appearance  which  these  present,  when  seen  by  transmitted  light,  is  that  of  a  section 
of  an  urinary  calculus  made  through  its  centre,  appearing,  like  it,  to  be  made  up  of 
concentric  layers.  When  viewed  by  reflected  light,  these  bodies  seem  to  be  vesicu- 
lar, and  filled  with  fluid,  the  quantity  of  which  appears  to  diminish  as  the  number  of 
layers  increases,  so  that  those  in  which  the  laminae  have  extended  as  far  as  the 
centre,  are  almost  flat.  Although  the  most  frequent  form  of  these  bodies  is  circular, 
yet  some  are  oval ;  occasionally  they  are  connected  with  a  fibre  of  the  arachnoid,  in 
such  a  manner  as  to  resemble  small  Pascinian  corpuscles.  One  remarkable  fact  con- 
nected with  these  bodies  is,  that  they  occur  in  the  arachnoid  of  almost  every  subject 
which  I  have  had  an  opportunity  of  examining,  and  that  no  part  of  the  membrane  is 
exempt  from  them ;  generally  they  are  solitary,  and  very  sparingly  distributed ;  but 
sometimes  they  are  in  clusters.  I  have  found  them  in  the  internal  Pacchionian 
glands  mixed  with  granular  matter,  and  the  same  kind  of  fibre  as  exists  in  most  parts 
of  the  arachnoid  membrane.  Their  diameter  varies  from  75,000  to  39.800ths  of  an 
inch.  I  have  observed  on  some  parts  of  the  arachnoid,  in  the  vicinity  of  a  cluster  of 
these  bodies,  cavities  of  a  similar  shape  and  size,  from  which  the  corpuscles  them- 
selves appear  to  have  been  dislodged.  From  this  circumstance,  as  well  as  from  the 
general  aspect  of  these  bodies,  they  seem  to  me  either  to  be  structures  altogether 
adventitious,  or  the  result  of  an  abnormal  deposition  in  diseased  corpuscles.  The 
tendency  which  they  may  be  observed  to  have  to  coalesce  when  several  smaller  ones 
occur  together,  evident  by  the  obliteration  of  those  portions  which  seem  pressed 
against  one  another,  and  the  union  of  the  remote  segments  to  form  a  single  outline 
enclosing  an  area  whose  figure  clearly  indicates  the  number  of  corpuscles  which  have 
united  to  form  it,  proves  them  to  be  something  more  than  mere  earthy  deposits,  such 
as  are  sometimes  found  in  the  choroid  plexuses,  or  even  than  mere  scrofulous  tuber- 
cles. Vogel  has  found  bodies  similar  to  these  in  the  choroid  plexuses;  in  these,  and 
in  the  pia  mater,  Dr.  E.  Harless  has  also  seen  them,  and  given  a  very  minute  account 
of  their  structure  in  a  number  of  Miiller's  Archives,  1845.  This  author  seems  to  think 
that  their  seat  is  in  the  arteries,  and  that  they  are  somewhat  allied  to  ossification  of 
these  structures;  but  their  occurrence  in  all  parts  of  the  arachnoid,  in  some  of  which 
there  are  nrobably  no  vessels,  is  opposed  to  this  view." 

Mr.  Rainey  regards  the  corpuscles  constituting  the  epithelium  of  the  choroid  plex 
uses  as  ganglionary,  and  details  his  reasons  for  this  opinion;  these,  however,  canno* 
be  admitted  to  be  decisive  on  this  point. 

"As  respects  the  supply  of  vessels  and  cerebro-spinal  nerves  to  the  arachnoid,  I 
may  observe,  that  the  arteries  are  few,  but  rather  large,  almost  sufficiently  so  to 
receive  a  small  injection  tube;  (I  have  preparations  of  these;)  and  that  cerebro-spinal 
nerves  may  be  traced  into  its  visceral  portion,  and,  with  the  microscope,  their  tubules 
can  be  seen  running  along  with  the  arachnoid  fibres,  into  which  they  appear,  from  the 
gradual  loss  of  their  tubular  contents,  to  degenerate." 


APPENDIX.  547 

Structure  of  the  Striped  Muscular  Fibrilla. 

At  page  358,  doubts  were  expressed  as  to  the  correctness  of  the 
view  entertained  by  Drs.  Carpenter  and  Sharpey,  in  reference  to  the 
structure  of  the  striped  muscular  fibrilla.  At  that  period,  the  author 
had  not  seen  any  of  Mr.  Lealand's  preparations,  on  the  examination 
of  which,  the  above-named  gentlemen  founded  their  opinion;  he  has 
since,  however,  been  favoured  by  Dr.  Carpenter  with  the  examination 
of  his  own  specimen,  and  this  would  certainly  appear  to  bear  out 
fully  their  opinion  of  its  cellular  constitution. 

Structure  of  the  Bulb  of  the  Hair. 

Further  opportunities  of  examination  have  satisfied  the  author  that 
the  vesicle  which  he  has  described  as  forming  a  portion  of  the  bulb 
of  the  hair  has  no  existence,  and  that  this  rests  immediately  upon  a 
compound  vascular  and  nervous  papilla. 

The  Synovial  Fringes. 

The  synovial  fringes  consist  of  branched  and  elongated  threads  or 
filaments,  which  taper  to  a  point,  and  each  of  which  is  supplied  with 
one  or  more,  according  to  its  size,  contorted  and  looped  blood-vessels; 
these,  however,  do  not  reach  the  whole  length  of  each  thread,  but 
terminate  at  one-third  or  one-half  its  length.  It  is  in  the  termina- 
tions of  these  filaments,  according  to  the  observations  of  Mr.  Rainey, 
that  those  cartilage-like  bodies  sometimes  found  loose  in  the  joints, 
especially  the  knee-joint,  are  first  formed.  The  threads  or  filaments  of 
which  the  synovial  fringes  are  constituted  are  of  such  length  and  so 
much  branched,  that  they  might,  at  first  sight,  be  mistaken  for  those 
of  some  conferva  of  the  genus  Cladophora. 

On  the  Anatomy  of  the  Sudoriparous  Organs. 

Mr.  Rainey*  describes  the  duct  of  the  sudoriparous  glands  as  con- 
sisting of  two  distinct  portions,  an  epidermic  and  dermic. 

The  epidermic  portion  is  of  a  conical  form,  the  base  being  directed 
towards  the  surface,  and  the  apex  situated  in  the  midst  of  the  cells 
which  form  the  deep  layer  of  the  epidermis;  it  is  constituted  of  cells 
which  are  flattened  and  elongated,  and  the  long  axes  of  which  are 

"On  the  Minute  Anatomy  of  the  Sudoriparous  Organs."  By  G.  Rainey. — Royal 
Med.  and  Chirur.  Society.     See  Lancet,  1849. 


548  APPENDIX. 

disposed  in  the  direction  of  the  length  of  this  portion  of  the  duct : 
below,  near  its  termination,  the  cells  are  thicker  and  less  flattened. 

The  dermic  portion  of  the  duct  is  also  of  a  somewhat  conical  shape, 
its  base  being  in  like  manner  directed  upwards,  and  its  parietes  being 
continuous  with  the  basement  membrane  of  the  dermis ;  this  portion, 
therefore,  is  of  a  totally  different  structure  from  the  former;  it  is 
described  by  Mr.  Rainey  as  being  lined  by  a  layer  of  epidermic  scales, 
which  get  gradually  indistinct  towards  the  gland,  and  its  upper  or 
expanded  part  as  receiving  the  termination  of  the  epidermic  division 
of  the  duct. 

This  description  of  the  duct  of  the  sudoriparous  gland,  so  far  as  I 
have  been  able  to  follow  it,  would  appear  to  be  in  its  main  particular 
correct,  it  consisting,  as  stated,  of  two  portions,  an  epidermic  and  a 
dermic ;  the  former  is  scarcely  to  be  regarded,  however,  as  any  thing 
more  than  an  appendage  to  the  dermic  part,  which  is  the  true  duct,  it 
being  little  more  than  a  definite  channel  through  the  epidermis. 

It  seems  to  me,  however,  to  be  incorrect  to  describe  the  epidermic 
portion  of  the  duct  as  commencing  in  the  deep  layer  of  the  epidermis; 
it  extends  beyond  and  far  deeper  than  this,  for  it  lines  the  whole  length 
of  the  true  duct,  and  this  not  merely  with  loosely  aggregated  cells, 
but  these  are  so  united  together  as  to  form  a  distinct  tubular  mem- 
brane, which  by  maceration  may  be  exhibited  as  such  (see  Plate 
XXIII.  fig.  2);  the  epidermic  cells  become,  in  fact,  continuous  with 
those  of  the  sudoriparous  gland  itself. 

Mr.  Rainey  has  noticed  the  fact  that  the  secretion  of  the  sudoripa- 
rous glands  in  the  palms  of  the  hands  and  soles  of  the  feet,  where  the 
sebaceous  glands  are  entirely  wanting,  is  of  a  greasy  character;  from 
this  circumstance  he  draws  the  conclusion  that  these  glands  secrete 
both  sweat  and  sebaceous  matter,  the  former  in  their  more  active 
state,  the  latter  in  their  less  active  condition. 

It  is  only  in  the  hands  and  feet,  where  the  epidermis  is  thick,  that 
the  epidermic  portion  of  the  sudoriparous  duct  assumes  importance. 


INDEX. 


PAGE 

437 


Adams,  Mr.    On  the  calculi  of  the  prostate 
Addison,  Dr.     His  belief  in  the  existence  of  a 

nucleus  in  the  red  blood  disc     .  .  .93 

Views  on  the  structure  of  the  red  blood  cor- 
puscle .  94 

Observations  on  the  white  corpuscles  of  the 
blood 103 

Further  observations  on  the  same    .  106.  Ill 

His  opinion  that  milk,  mucus,  and  bile  are  the 
visible  fluid  results  of  the  first  dissolution  of 
the  cells  ..... 

His  opinion  that  the  white  corpuscles  are  the 
foundations  of  the  tissues  and  the  special 
secreting  cells.        .... 

On  the  presence  in  increased  quantities  of  the 
white  corpuscles  in  the  hard  and  red  basis 
of  boils  and  pimples,  and  in  the  skin  in  scar- 
latina,   ...... 

His  opinion  that  mucous  and  pus  globules  are 
altered  colourless  blood  corpuscles 

His  opinion  that  out  of  the  white  corpuscles 
of  the  blood,  all  other  corpuscles  met  with 
in  the  body  are  formed 

On  the  action  of  liq.  potass,  on  pus 


LOG 


107 


On  epithelial  scales  in  the  air  cells  of  the  lungs  397 


On  tuburcles  of  the  lungs 
Aggregated  or  Peyer's  glands 
Albinoes,  state  of  pigmentary  cells  in 

Hair  of      . 
Albinus.    The  first  describer  of  the  nail 
Alcohol  and  Water  .... 

Allen,  microscope  of  ... 

Alpaco,  blood  of  ...  . 

Alumina,  acetate  of 
Ancell.     On  the  increased  quantities  of  white 

corpuscles  in  the  blood  in  inflammatory 

affections     ..... 
Andral  and  Gavarret.      On    the    mammillated 

appearance  of  the  red  blood  discs    . 
Important  researches  on  the  pathology  of  the 

bloud  ..... 

Andral,  A.   G.  Camus,  and  Lacroix.     On  the 

Pacinian  bodies 
Annelidie,  blood  of 
Arachnoid  Membrane 

Ganglionary,  character  of     . 
Area  Vasculosa 
Arteries,  injection  of    . 
Asphaltum  Cement 
Axilla.    New  tubular  gland  in. 
Axillary  glands.    Structure  of 


138 


.  386 

80 

.  543 

543 

.  130 

39 

.    49 

Plate  lvii. 

130 


Baly.    His  opinion  that  the  white  globules  are 

red  blood  corpuscles  in  process  of  formation  112 
Bariy,  Dr.     His  belief  in  the  existence  of  a 
nucleus  in  the  human  red  blood  discs    .  93 

Views  on  the  structure  of  the  red  blood  cor- 
puscle   .  .  .  .  .  .94 

Views  on  the  white  blood  corpuscle  .        107 

His  opinion  that  the  tissues  are  formed  by 

direct  apposition  of  the  blood  corpuscles    .  107 

His  discovery  of  spermatozoa  on  the  ovary        233 

Bat.    Hair  of  .  .  .  .304 

Bear.    Spermatozoa  of  224 


Beclard.    On  the  disappearance  of  the  fat  vesicle  261 

Becquerel  and  Rodier.  Researches  on  the  blood  158 

Berzelius.    Analysis  of  healthy  in  ine      .  .  246 

Bidder.     On  the  peripheral  distribution  of  the 

gelatinous  nerve  filaments  .  .        3S2 

On  the  structure  of  the  kidney  .  .  450 

On  the  structure  of  the  Malpighian  body  .        451 

Bile 042 

Epithelium  in  .  243 

Cell-like  bodies  in  ...  243 

Corpuscles  of  liver  in  243 

Meconium  .....  243 

Birds,  fat  of  .  .  .  .        255 

Malpighian  bodies  of  .  .  .  464 

Bisohoff.     His  discovery  of  living  spermatozoa 

in  the  rabbit  eight  days  after  intercourse        227 

His  discovery  of  spermatozoa  on  the  ovary  itself  233 

On  the  structure  of  the  kidney        .  .        450 

Blood  .  .  .  .  .  ,79 

Definition  of  .  .  .  .  .80 

Red  blood  .  .  .  ,  .80 

Colourless  blood        ....         80 

Composition  of    .  .  .  .  .80 

Coagulation  of  without  the  body     .  .         80 

Death  of   .  .  .  .  .  .80 

Quantity  of  in  the  body       ...  80 

Blood  of  annelidie  .  .  .  .80 

Clot 81 

Coagulation  of  blood  within  the  vessels  after 

death 86 

Motling  of  .  .  .  .85 

Fluid  state  of  after  death  .  .      '     .    87 

Globules  of    .  .  .  .  .88 

Red  •  .  .  .  .  .89 

White  .....       100 

Venous  and  arterial  blood         .  .  .  134 

Causes  of  inflammation        .  .  .        140 

Exciting  cause     .....  140 

Proximate  causes       ....        140 

Pathology  of  blood         ....  142 

Blood  in  the  menstrual  fluid  .  .        160 

Transfusion  of  blood      ....  160 

Importance  of  a  microscopic  examination  of 

the  blood  in  criminal  cases  .  .        164 

Corpuscles,  preservation  of  .  .  170 

4i         size  of     .  .  .  .79 

Examination  of  .  .  .  .  ,  169 

Stains,  how  detected  by  the  microscope     .        164 
Bone.    Structure  of      ....        317 

Cancellous  structure       .  317 

Lamellie  of     .  .  .  ,        317 

Medullary  cells  of      .  .  .  .        317 

Communications  of  ...  ..  317 

Contents  of     .  .  .  .  .        318 

Canalicular  structure  of  .  318 

Haversian  canals  of  .  .  .  .        318 

Contents  of  ditto  ....  319 

Arterial  and  venous  Haversian  canals        .        319 
Lamellte      ...  ...  319 

Number  and  arrangement  of  ditto  .  .        320 

Structure  of  ditto  .  .  .  .320 

Bone  cells       .  .  .  .  .321 

Differences  of  opinion  as  to  nature  of  .  .  321 

Form  of  .  .  .  .321 


550 


INDEX. 


PAGE 
.    322 

32i 
.  329 

330 
.3-22 

32-2* 
.  323 

324 
.  324 

325 
.  325 

326 
.  330 

331 
.  332 

332 
.  334 


Bone.    Canaliculi  of  ... 

Size  of  bone  cells  in  different  animals 

Development  of  ditto     .... 

Comparison  of  to  stellate  pigment 

Marrow  of  bones  .... 

Periosteum  of  ditto  .... 

Vessels  of  ditto   ..... 

Nerves  of  d:tto  .... 

Growth  of  ditto  ..... 

Development  of  ditto 

Intra-membraxious  term  of  ossification 

lntra-cartdaginous  form  of  ditto 

Formation  of  medullary  cavity 

Ditto  of  medullary  ceils 

Ditto  of  Haversian  canals 

Accidental  ossification 

To  make  sections  of 
Bowerbank,  Mr.     On  the  size  of  the  human 

blood  disc   .  .  .  . 

Bowman,  Mr.  On  the  lining  membrane  of  the 
F;diopiaii  tubes 

His  doubts  as  to  the  existence  of  a  lobular  bil- 
iary plexus  .... 

His  opinion  that  the  series  of  secreting  cells 
represent  the  continuance  of  the  biliary- 
ducts 

On  the  ciliated  epithelium  at  the  neck  of  the 
Malpighian  dilatations 

His  opinion  that  the  afferent  vessel  of  the 
Malpighian  tuft  pierces  the  ddated  extremity 
of  tne  tube  ....  444.  451 

On  the  termination  of  the  renal  artery  on  the 
Malpighian  bodies  .  .  .        '146 

On  tiie  uses  of  the  Malpighian  body     .  .  447 

Branchiostoma  Lubricum        .  .  .80.  116 

Breschet.  On  the  presence  of  Pigment  in  the 
membranous  labyrinth  of  the  ear  of  mam- 
malia    .  .  .  .  .  .287 

On  imbibition  of  cartilages  .  .        312 

On  the  communication  of  the  medullar}'  cells 
of  bone  .....  317 

On  a  system  of  osseous  canals  in  flat  bones 


91 
413 


425 


430 


444 


Brewster,  Sir  David,  on  the  fibres  of  the  crystal- 
line lens  .....  523 
Bronchial  glands  ....        419 
Bronchial  tubes   .  .  ...  305 
Structure  of    .           .           .  .  .        395 
Larger  tubes        .....  395 
Smaller  ditto  .....        395 
Mucous  membrane  of     .           .           .  .396 
Epithelium  of             ....        39) 
Muscular  fibre  of            ....  396 
Bruimer's  glands           .           .           .            420, 421 
Structure  of          ....  .  421 
Distribution  of.    (Vide  mucous  Glands.) 
Brunner's  microscope        .            .            .  .31 
Brans.    On  the  membrane  lining  the  cavities  of 
the  true  cartilages        ....  307 
On  the  nature  of  bone  cells              .            .        321 
Buccal  glands          .....  419 
Buffy  Coat  of  Blood,  conditions  favourable  to  the 

formation  of  ...         85 

Built-up  cells  .  .  .  .55 

Cabinets  for  objects  .  .  .  .64 

Cadaveric  rigidity  ....        366 

Canada  balsam.    Method  of  mounting  objects  in  62 

Camelidae.    Blood  of  .  .  .90 

Of  dromedary  .  .  .90 

Of  alpaco.  .  .  .  .  .90 

Of  vicugna     .....         90 

Of  llama 90 

Capybara,  blood  of  .  .  .92 

Carnivora,  blood  of  .  .  .  .92 

Carpenter,  Dr.    On  the  structure  of  the  striated 
muscular  fibrilla     ....        358 
On  the  analogy  between  striped  and  unstriped 

muscular  fibres  ....  369 

On  the  analogy  between  certain  cartilage  cells 
and  certain  alga    ....       314 


PAGE 

Cartilage.    General  structure  of    .  .  .  306 

Division  of  into  true  and  false         .  .        306 

True  Cartilages  ....  306 

Enumeration  of  ...  .        306 

Structure  of 306 

Matrix  of  .  .  .  .306 

Cavities  of  .  .  .  .  .307 

Primary  cells  of         ....       307 

Secondary  cells  of  ...  .  308 

Nuclei  of        .....       309 

Distinction  of  cartilage  into  true  and  false 
fibro  cartilages,  to  some  extent  artificial 

Conversion  of  true  into  fibro  cartilage 

Union  of  true  cartilage  with  ligament 

Fibru-cartUages 

Structure  of         ...  . 

Cells  of  ... 

Fibres  of  . 

Enumeration  of         .  .  . 

Nutrition  of  cartilage 

Pericondrium  of 

Vessels  of  cartilage        . 

Pathology  of  . 

Ossification  of  .  .  . 

Ulceration  of  . 

Atrophy  of  ...  . 

Growtn  and  development  of  cartilages 

Of  the  cells  .... 

By  division  of  ditto   . 

By  cytoblasts       .... 

By  parent  cells 

Comparison  of  cartilage  cells  to  certain  alga? 

Growth  and  development  of  the  inter-cellular 
substance  .... 

By  a  deposit  of  new  layers  . 

By  thickening  of  the  wails  of  the  cavities 

Enchondroma 

Uses  of  cartilage .... 

To  examine     .... 
Caruncuia  Lachrymalis,  structure  of 
Cat.     Uulb  of  hair  of   . 

Blood  vessels  of  stomach  of 
Cells.    Thin  glass 

Drilled      . 

Tube    ... 

Built-up        . 

Gutta-percha  .... 
Cements.    Asphaltum 

Canada  balsam 

Compound  .  .  . 

Gum  Arabic    .... 

Japanner's  gold  size 

Marine  glue    .... 

Sealiug-wax         .... 
Cerebellum,  ganglion  cells  of  arbor  vitae 

Ditto  of  corpus  dentatum 
Ceruminous  glands 

Structure  of 
Charriere's  syringe        .  . 

Chevalier's  microscope 
Chromic  acid 
Chyle  .... 

Analysis  of     . 

Molecular  base  of 

Granular  corpuscles  of 

Chylous  blood 

Oil  globules  of  chyle 

Minute  spherules  of 

Coagulum  of  . 

Serum  of  .... 

Nature  of  .  .  . 

Contrasted  with  lymph  . 

Colour  of  in  thoracic  duct    . 

Examination  of  . 
Cilia        ..... 
Circulation,  capillary 

In  embryo  of  the  chick  &c. 
(Extremities  of  young  spiders,  fins  of  fishes, 
gills  of  tadpole  and  newt,  tail  of  water-newt, 
web  of  frog's  foot  and  tongue  of  frog.; 


309 
309 
309 
309 
310 
310 
310 
310 
311 
311 
311 
312 
312 
312 
312 
312 
312 
312 
313 
313 
313 

314 

314 

314 

315 

315 

316 

418 

304 

411 

54 

54 

54 

55 

55 

49 

50 

50 

51 

49 

50 

50 

377 

377 

441 

441 

41 

30 

58 

67 

68 

69 


69 
69 
69 
69 
69 
70 
70 
78 
269 
125 
129 


INDEX. 


551 


PACK 

.    81 


Clot.    Formation  of 
Ditto  in  biood  after  freezing  .  •  81 

Constitution  of     .  .  .  .  .82 

Length  of  time  for  formation  of      .  .         8-2 

Characters  of  in  health  and  disease      .  .    82 

Ditto  in  diseases  of  a  sthenic  character      .  83 

Ditto  of  in  diseases  of  an  asthenic  character        83 
Softening  of  fibroin        .  .  .  .83 

Buffy  coat  of  clot       ....         83 
Mode  of  formation  of     .  .  .  .84 

Adherence  of  red  corpuscles  in  rolls  in  clot  of 

inflammatory  blood  ...  84 

Conditions  favourable  to  the  formation  of  clot    85 
Cupping  of  .  .  .  .85 

To  what  owing    .  .  .  .  .85 

Condition  of  red  globules  in  85 

Colostrum.    Corpuscles  of  201 

Disappearance  of  ditto         .  .  .        21)2 

Colostrum  corpuscles  peculiar  to  the  human 

subject 203 

Purgative  qualities  of  colostrum  .  .  203 

Division  of  pregnant  women  into  three  classes 
founded  on  its  characters  .  .  .        207 

Comparetti.    On  the  presence  of  pigment  in  the 
membranous  labyrinth  of  the  ear  of  mam- 
malia    ......  287 

Compressor,  the  ....  30 

Coppin,  Mr.  J.    On  the  circulation  in  the  tongue 

of  the  frog 128 

Corpora  Wolffiana    .  .  .  .449 

Corpuscles.     Of  the  blood.     Red  corpuscles        .    89 
Colouring  matter  of  .  .  .  .95 

Uses  of     .  .  .  .  .  .97 

Causes  of  colour  of    .  .  .  .98 

Iron  in  .  .  .  .  .98 

Origin  of         ....  115 

Phases  of  the  development  of  .  .  .116 

Final  condition  of  .  ,  .119 

Blood  globules  of  reptiles,  fishes,  and  birds    .  123 
Ditto  of  CamelidaB    ....        123 

Ditto  of  the  embryo  of  fowl      .  .  .  131 

Ditto  of  young  frog   ....        131 

Blood  corpuscles,  dissolution  of  .  .  132 

Blood  corpuscles  of  adult  fowl        .  .        132 

Ditto  of  tritons  and  frogs  .  .  .  133 

Effects  of  reagents  on  the  red  corpuscles  .        135 
Modifications  the  results  of  different  external 
agencies  .....  138 

Ditto  the  effect  of  commencing  dessication        138 
Ditto  the  result  of  decomposition  occurring  in 

blood  abandoned  to  itself,  without  the  body  139 
Ditto  the  effect  of  decomposition  in  the  blood 

within  the  body,  after  death         .  .        139 

Effects  of  certain  remedial  agents  upon  the 

constitution  and  form  of  the  red  blood        .  162 
Effects  of  iodine  on  ditto      .  .  .        163 

Peculiar  concentric  corpuscles  in  blood       121,  122 


Of  Mucus.    Structure  of   . 
Nuclei  of,  single  and  compound 
Form  of    . 

Size  of  ... 

Properties  of 
Nature  of 
Identity  of  with  the  pus  corpuscle 


PAGE 

.  174 
174 

.  175 
176 

.  176 
176 

.  177 


White  corpuscles  of  blood.    Number  of    .        100 

Size  of 101 

Form  of 101 

Structure  of    .  .  .  .  .        101 

Nucleus  of 102 

Properties  of  .  .  .  .  .        103 

Position  of  in  capillaries  .  .  .  104 

Motion  of  in  ditto      ....        105 
Uses  in  connexion  with  secretion         .  .  105 

Uses  in  connexion  with  nutrition    .  .        107 

Aggregation  of  in  capillaries     .  .  .  108 

Increased  quantities  of  in  disease   .  .        109 

Processes  by  which  they  may  be  separated 

from  the  red  globules  .  .  .  109 

Origin  of  .  .  .  .110 

Opinions  concerning  ....  110 
Different  names  for  ....  Ill 
("  Central  Particles  "  of  Hewson ;  "  Escaped 
Nuclei ; "  "  Parent  Cells  "  of  Barry ;  "  Tissue 
Cells  "  of  Addison  ;  "  Fibrinous  Globules  " 
of  Mandl;  "Granule  Cells"  of  Wharton 
Jones ;  "  Exudation  Corpuscles  "  of  Gerber ; 
"  Lymph  Corpuscles  "  of  Miiller.) 


Mucous  corpuscles,  young  epithelial  scales        179 
Of  Pus.   identity  of  pus  with  mucous  corpuscles  183 

Nature,  origin,  and  formation  of  pus  corpus- 
cles       ......  184 

Cowper's  glands  .  .  .  420, 421 

Creosote       .  .  .  .  .  .    57 

Crustacea,  fat  of  .  .  .  .        255 

Crusta  Petrosa         .....  335 

Cruveilhier,  on  the  calculi  of  the  prostate     .        437 

Davy,  Dr.    On  the  increased  quantities  of  white 
corpuscles  in  the  blood  in  inflammatory 
affections  .....  109 

On  the  presence  of  spermatozoa  in  the  fluid 
of  the  urethra  after  stool  in  a  healthy  man     236 
Death.    Signs  of  .  .  .        .  86 

Real  and  apparent  ....  86 

Coagulation  of  the  blood,  the  most  certain 
sign  of     .  .  .  .  .  .87 

Delia  Torre.    On  the  annular  form  of  the  red 

blood  disc 93 

Donne.  His  disbelief  in  the  existence  of  a  nucleus 
in  the  red  blood  disc     .  .  .  .93 

On  the  increased  quantities  of  white  corpus- 
cles in  the  blood  in  disease  .  .        109 
Opinions  in  reference  to  the  blood  globules    .  110 
His  opinion  that  the  white  globules  are  red 

blood  corpuscles  in  process  of  formation       112 
His  observations  on  the  conversion  of  milk 

globules  into  white  corpuscles           .  .  112 
On  the  transition  of  white  globules  to  red  cor- 
puscles     113,  114 

Reasons    in  favour-  of  the  opinion  that  the 

red  globules  are  formed  out  of  the  white       115 
Opinion  of,  as  to  the  cause  of  the  mammilated 

appearance  of  the  red  blood  disc  .        138 

Vaginal  tricho-monas  of  181 

Vaginal  vibrios  of  .  .  .        182 

Opinions  as  to  the  nature  of  pus  globules  86 

Venereal  vibrios  of   .  .  .  .        194 

On  cheese  globules  ....  196 

The  discoverer  of  colostrum  corpuscles     .        201 
His  statement  that  the  colostrum  corpuscles 

are  soluble  in  ether     ....  202 
On  the  recurrence  of  colostrum       .  .        204 

Condition  of  milk  after  confinement,  in  con- 
stant relation  with  its  state  during  gestation  207 
His  division  of  pregnant  women  into  three 
classes,  founded  on  the  characters  of  the  col- 
ostrum during  the  last  months  of  gestation     207 
Lactoscope  of  .  .  .  .211 

On  the  formation  of  butter  .  .  .        215 

His  detection  of  the  spermatozoa  in  the  vagi- 
na on  the  second  day  .  .  .  227 
Double  decomposition.    Injections  by          .         44 

Drilled  Cells 54 

Dromedary.    Blood  of  ...         90 

Dry  Way.    Method  of  mounting  objects  in  the     59 

Dujardin.    On  the  human  spermatozoon       223,  224 

His  statement  that  spermatozoa  lived  thirteen 

hours  in  the  testicle  after  death        .  .  227 

Ear,  structure  of.    See  Hearing,  organ  of     .        523 

Eble.  On  the  hair  at  its  full  term  of  development  298 

On  nerves  in  the  bulb  of  the  hah  of  the  cat      304 

Elephant.    Blood  of  .  .  •  -92 

Malpighian  bodies  of  44? 

Enchoudroma         .  315 

Epidermis.   Form,  size,  and  structure  of  cells  of  277 

Correspondence  of  to  epithelium  .  .  277 

Disposition  of  ....        278 

Ditto  of  line9  on  the  surface  of  .  '  Sm 

Effects  of  water  on    .  .  •  .279 


552 


INDEX, 


Epidermis  of  white  and  coloured  races 

Destruction  and  renewal  of 

Uses  of 

Pathology  of  . 

Mr.  Rainey's  description  of 

Examination  of 
Epithelium.     Constitution  of 

Distribution  of 

Different  forms  of 

Tesselatcd  variety      . 

Form  of  cells  of  . 

Size  of 

Structure  of  .  . 

Distribution  of 

Colloidal  variety  . 

Form  and  size  of  cells  of 

Structure  of 

Naked  conoidal  variety 

Distribution  of     . 

Ciliated  variety 

Distribution  of     . 

Development  and  multiplication  of  epithel 

Nutrition  of  dito  .... 

Destruction  and  renewal  of  ditto    . 

Uses  of 

Methods  of  examination  of 

Epithelial  Tumours 
Ether,  injections 

Eustachian  glands  .... 
Evans,  Dr.  Julian.  On  the  structure  of  the  spl 
Eye.     See  Vision 

Dissection  of  . 


PAGE 

.  279 
279 

.  280 
278 

.  281 
281 

.  204 
265 

.  205 
265 

.  265 
206 

.  206 
207 

.  207 
267 

.  268 
208 

.  208 
208 

.  270 

71 

272 

272 

u7;j 

275 

275 

43 

419 

een  489 

509 

5J3 


mm 


Fat.    Vesicles  of    . 

Contents  of  ditto 

Form  of  ditto 

Size  of  ditto   . 

Colour  of  ditto    . 

Consistence  of  ditto  . 

Structure  of  ditto 

Distribution  of  fat 

Quantity  of 

Disappearance  of 

Uses  of 

Distinction  of  fat  vesicles  from  oil  globules 

Development  of  the  fat  vesicle 

Examination  of 
Fibrin.    Softening  of 

Fibrillation  of 
Fibrous  Tissue 

White  Fibrous  Tissue 

Enumeration  of  parts  constituted  of 

Morphous  form  of     . 

Amorphous  form  of 

Condensed  form  of    . 

Reticular  form  of 

Areolar  form  of         .  .  . 

Structure  of 

Action  of  acetic  acid  on 

Yellow  fibrous  tissue      .  . 

Enumeration  of  parts  constituted  of 

Structure  of 

Varieties  of    . 

Peculiar  arrangement  of 

Mixed  fibrous  tissue  .  . 

Nuclear  form  of  fibrous  tissue 

Development  of  white  fibrous  tissue 

Ditto  of  yellow  fibrous  tissue    . 
Fishes.    Bone  cells  wanting  in  bone  of 
Fluids.     Organized 

Lymph 

Chyle 

Blood  . 

Mucus 

Pus      . 

Semen      .  .  . 


Saliva 

Bile 

Sweat 


.  254 

254 
.  254 

255 
.  255 

255 
.  255 

259 
.  260 

261 
.  262 

262 
.  538 

263 
.    83 

353 
.  346 

346 
.  346 

347 
.  347 

347 
.  347 

347 
.  347 

347 
.  348 

349 
.  348 

349 
.  350 

353 
.  349 

352 
.  352 

322 

.    66 

67 

.    67 

79 

.  171 

183 
.  218 

240 
.  241 

242 
.  243 


Fluids.    Urine 

Pancreatic  fluid 

Lacrymal  ditto    . 

Gastric  ditto    . 

Preparation  of 

For  mounting  objects 

Alcohol  and  Water 

Goadby's  Solutions    . 

Acetate  of  Alumina 

Creosote 

Glycerine 

Canada  balsam 

Salt  and  Water    . 

Naphtha 

Chromic  acid 

Method  of  mounting  objects 
Follicles.    Of  stomach 

Of  small  intestines    . 

Of  Lieberkiihn 

Of  large  intestines     . 

Form  of 

Epithelium  of 

Blood-vessels  of  . 

Follicles  of  uterus     . 

Of  Fallopian  tubes 

Of  vagina 

Of  resophagus     . 

Of  neck  of  uterus 

Of  vesicula  seminalis     . 

Of  Schneiderian  membrane 
Forceps,  dissecting 

Cutting 
Frog.    Tongue  of.    Mode  of  exhibition  of 


TAGE 

.  245 

250 

.  250 

250 

.    56 

56 

.    56 

56 

.    57 

57 

.    57 

57 

.    57 

58 

.    58 

59 

.  410 

410 

.  410 

410 

.  410 

410 

.  411 

413 

.  413 

419 

.  418 

418 

.  418 

419 

.    33 

34 

.  126 


Gall  Bladder.    Structure  of     .  .  .        429 

Galiina?.    Spermatozoa  of  220 

Gastric  juice       .....        250 
Gelatine,  injections  with    .  .  .    48 

Gerber.    On  the  relation  between  the  size  of  the 
blood  globules  and  the  capillaries  .  92 

His  belief  in  the  existence  of  a  nucleus  in  the 

red  blood  disc  .  .  .  .  .93 

On  the  structure  of  the  spermatic  animalculi 

of  the  guinea-pig  .  .  .  223 

On  the  stellate  bodies  observed  in  decomposing 

fat  vesicles        .....  259 
His  description  of  the  epithelium  of  the  ven- 
tricles as  a  tesselated  ciliated  epithelium        271 
On  nerves  in  the  bulb  of   the    hail-  of   the 

guinea-pig        ....  304 

On  the  nature  of  bone  cells  .  .        330 

Gerlach.    On  the  structure  of  the  kidney  .  450 

On  the  structure  of  the  Malpighian  capsule       451 

Gingival  glands       .....  420 

Glands.    Definition  of  ....        406 

Classification  of     .  .  .  .  .408 

a.  Unilocular  glands  .  .  .  410 
Follicles  of  stomach  .  .  .  410 
Ditto  of  large  intestines  .  .  .  410 
Ditto  of  Lieberkiihn  .  .  .  .410 
Stomach  tubes  ....  412 
Fallopian  and  uterine  tubes  or  follicles  413 
Solitary  gland3  .....  413 
Aggregated  or  Peyer's  glands.          .           .        414 

b.  Multilocular  ditto  ....  414 
Sebaceous  ditto  ....  414 
Meibomian  ditto  ....  416 
Glands  of  the  hair  follicles  .  .  .  416 
Caruncula  lachrymalis  ....  418 
Glands  of  nipple  .  .  .  .418 
Ditto  of  prepuce  ....  418 
Mucous  glands  .  .  .  .  418 
Labial  ditto  .  .  .  .  .419 
Buccal  ditto  .  .  .  .  .419 
Tonsillitic  ditto  .  .  .  .  .419 
Lingual  ditto  .  .  .  419 
Tracheal  ditto  .  .  .  .  '419 
Bronchial  ditto  .  .  .  .419 
Palatine  ditto  .  .  .  .  .419 
Pharyngial  ditto         .           .           .           .413 


INDEX 


553 


PAOE 

Glands  of  uvula      .  .  .  .  .419 

Dilto  of  Eustachian  tubes    .  .  .419 

Brunner's  glands  .  .  .      420, 421 

Cowper's  ditto  .  .  .  420,  421 

Gingival  ditto  .....  420 
Uterine  ditto  .....  420 
Vaginal  ditto        .  .  .  .  .420 

Lenticular  ditto         ....        420 

c.  Lobular  ditto  .....  422 
Salivary  ditto  .  .  .  .422 
Mammary  glands             ....  423 

Liver 423 

Prostate  gland      .....  430 

d.  Tubular  glands      ....        437 

Sudoriferous  ditto  ....  437 

Axillary  ditto  .  .  .  .441 

Ceruminous  ditto  ....  441 

New  tubuiar  gland  in  axillae  kidneys  .        441 

Testis        .  .  .  .  .  .483 

g.   Vascular  glands    ....        484 

Thymus  gland      .  .  .  .  .  484 

Thyroid  gland  .  .  .  .486 

Supra-renal  capsule        ....  488 

Spleen  .....        489 

/.  Absorbent  glands        ....  492 

Lacteal  or  mesenteric  glands  .  .        492 

Lymphatic  glands  ....  492 

Villi  of  intestines       ....        493 

Glass  slides  .  ....    51 

Cells    .  .     '      .  .  .  .54 

Thin 51 

Instruments  for  cutting         ...  52 

Globules  of  milk    . '  .  .  .  .197 

Goadby's  solutions  *  .  56 

Goat.    Blood  of     .  ...    92 

Goodsir.    On  the  general  development  of  the 

teeth     .  .  .  .  .  .340 

On  the  classification  of  glands         .  .        408 

On  the  epithelium  of  the  villi    .  .  .  493 

On  the  cells  developed  during  absorption  in 
ditto  .....        494 

Grallas.    Spermatozoa  of  .  .  .  .  220 

Gruby  and  De  la  Font.  M.M.    On  blood  discs  in 
chyle  .....  71 

Gueterbock.    His  opinion   that  the  colostrum 

corpuscles  are  true  cells  .  .  .  202 

Guinea-pig,  spermatozoa  of     .  .  .        219 

Gulliver,  Mr.     Observations  on  the  molecular 

base  of  the  chyle  in  the  blood  .  .    69 

On  the  lymphatics  of  the  spleen     .  .  71 

On  the  characters  of  the  blood  discs  in  the  chyle  71 

His  opinion   in  favour  of  Hewson's  views  of 

the  thymus  .....  72 

On  the  blood  of  the  vicugna  and  llama  .    90 

On  blood  corpuscles  in  states  of  disease      .        91 
On  the  relation  in  the  size  of  the  blood  cor- 
puscles among  the  mammalia,  and  that  of 
the  animal  from  which  they  proceed  .    92 

On  the  dimensions  of  the  red  blood  discs  of 

the  elephant,  capybara,  and  napu  musk-deer     92 
His  disbelief  in  the  existence  of  a  nucleus  in. 

the  red  blood  discs  ...  93 

His  measurement  of  the  human  colourless 
blood  corpuscle  ....  101 

His  observations  on  the  presence  of  white  cor- 
puscles in  the  blood  in  unusual  quantities  in 
inflammatory  affections     .  .  .        109 

His  opinion  that  the  white  globules  are  red 

blood  corpuscles  in  process  of  formation     .  112 
His  opinion  that  blood  discs  are  the  escaped 

nuclei  of  the  white  corpuscles     .  .        117 

On  the  blood  of  birds  after  a  full  meal       .        118 
On  concentric  corpuscles  in  the  blood,  which 
he  has  styled  "  Organic  Germs,"  or  "  Nucle- 
ated Cells"       .  .  .  .  .122 

Gum  Arabic  cement     .  .  .51 

Gurlt.     His  statement  that  the  fat  vesicles  in 

lean  animals  contain  serosity,  and  not  grease  261 
Glycerine      .  .  .  .  .  .57 

Gutta-percha  cells  ....  55 


PAGE 


Haidlen.    Inorganic  components  of  milk  of  cow, 
according  to  ....        195 

Hair.    Form  of 291 

Size  of 292 

Structure  of    .  .  .  .  .292 

Ditto  of  root  of    .  . '  .  .  .292 

Ditto  of  bulb  of         .  .  .  .        2y3 

Ditto  of  sheath  of  ...  .  293 

Dilto  of  shaft  of  .  .  .294 

Ditto  of  cortex  of  .  .  .  .294 

Ditto  of  fibrous  layer  of  .  295 

Ditto  of  medullary  canal  of  .  .  296 

Ditto  of  follicle  of      .  .  .  .        297 

Growth  of  hair 298 

Regeneration  of         ...  .        298 

Nutrition  of  .  .  .  .299 

Distribution  of  ....        300 

Number  of  hairs  in  different  situations  .  300 

Erection  of  .  .  .  .        301 

Colour  of 301 

Gray  hair 302 

Properties  of  hair  ....  302 

Hairs  of  different  animals     .  .  .        303 

(Of  the  musk  deer,  sable,  mouse,  bat,  martin)  304 
Uses  of  hair  .....  304 
Transverse  sections  of    .  .  .  .  305 

Sections  of,  to  mount  .  .  .        305 

Hair  Follicles.    Glands  of  416 

Distribution  of  ...  .        416 

Structure  of  ....  .  416 

Binary  arrangement  of  .  .  .        417 

Steatozoon  folliculorum  .  .  .  417 

Havers.  Glands  of  ....  260 
Haversian  canals  .....  318 
Hearing.    Organ  of  .  .  .        523 

External  ear  .....  523 
Auricle,  structure  of  ...        523 

Cartilages  of        ....  523 

Muscles  of  .....  524 
Auditory  canal  .....  524 
Cartilaginous  part  of  ...        524 

Osseous  ditto  .....  524 
Sebaceous  glands  of  ...        524 

Ceruminous  ditto  ....  524 

Muscular  fibres  in  .  .  .        524 

Middle  ear  .....  524 

Tympanum  .....  524 
Structure  of         ....  524 

Tympanic  cavity  ....  525 
Structure  of  membrane  of  .  .  525 

Openings  into  ....        525 

Ossicles  and  muscles  of  ...  525 

Transparent  ceils  in  .  .  .  .       525 

Pigment  cells  in  .  .  .  .  525 

Internal  ear  .....  525 
Osseous  labyrinth  ....  525 

Membranous  ditto  ....  525 
Perilymph  .....  525 

Endolymph     .  .  .  525 

Structure  of  the  spiral  lamina  of  the  cochlea  526 
Denticulate  lamina  ....  526 
Membranous  zone  ....  527 

Structure  of  the  cochlearis  muscle  .        527 

Cochlear  ligament  ....  528 

Muscular  zone  ....        528 

Epithelium  of  scalae  ....  528 
Structure  of  the  cochlear  nerves     .  .        529 

Of  the  membranous  labyrinth  .  .  ,  529 

Utriculus 529 

Sacculus    .  .  .  .  .  .529 

Membranous  semi-circular  canals   .  .        530 

Otolith      .  .  .  .  .  .531 

Otoconia        .....        531 

Of  the  vestibular  nerves  .  .  .  531 

Of  the  auditory  nerves     .  .  .        532 

Hedgehog.    Structure  of  spines  of  .  .  304 

Henle,  M.     Theory  of  the  changes  of  the  colour 

of  the  blood  .  .  .  .136 

Opinions  as  to  the  nature  of  the  white  corpus- 
cles of  blood,  lymph,  chyle,  mucus,  and  pus    178 


554 


INDEX. 


PAGE 

Henle.    His  opinions  as  to  the  structure  of  the 
milk  globules  :  :        197 

On  the  application  of  acetic  acid  to  the  milk 

globules  .  .  .  .  .199 

His  opinion  that  the  colostrum  corpuscles  are 
aggregations  of  granules  in  a  mucoid,  sub- 
stance        .....        202 
On  the  structure  of  spermatozoa  .  .  223 

On  the  membrane  of  the  fat  vesicle  .        256 

On  the  nucleus  of  the  fat  vesicle  .  .  257 

On  the  stellate  bodies  observed  on  decom- 
posing fat  vesicles  .  .  .        259 
On  the  presence  of  fat  in  the  blood  after  re- 
peated bleedings         ....  262 
On  the  absence  of  epithelium  in  the  bursae       265 
His  description  of  the  epithelium  of  the  ven- 
tricles as  a  cuneiform  ciliated  epithelium     .  271 
On  the  position  of  the  pigment  granules  in  the 

cells            .....        288 
On  the  fibres  of  the  fibrous  layer  of  the  hair     295 
On  the  medullary  canal  of  hail-        .            .        296 
On  the  membrane  of  the  cavities  of  true  car- 
tilage     307 

On  the  arrangement  of  the  cells  of  articular 
cartilage     .....        308 

On  certain  large  cells,  presenting  in  their  in- 
terior a  cavity  in  the  cartilage  of  the  epi- 
glottis .  .  .  .  .  .311 

On  the  increase  of  the  inter-cellular  substance 
of  cartilages  by  the  thickening  of  the  mem- 
brane of  the  cavities         .  .  .        314 
On  the  structure  of  the  lamellae  of  bone         .  320 
On  the  nature  of  bone  cells             .  .        330 
On  the  structure  of  the  inter-tubular  substance 
of  dentine        .....  337 

On  a  peculiar  arrangement  of  the  fibres  of 
elastic  tissue  ....        350 

On  the  disposition  of  gelatinous  nerve  fibres    380 
On  the  proportions  of  gelatinous  nerve  fila- 
ments in  different  nerves  .  .        382 
On  the  arrangement  of  the  gelatinous  nerve 
filaments  in  ganglia     ....  383 

On  the  development  of  nerve  cells  on  the  sur- 
face of  the  convolutions  of  the  brain      .        390 
On  the  epithelium  of  the  choroid  plexuses     .  538 
Herbivora.    Blood  of    .  .  .  .92 

Hewson.    On  the  lymphatics  of  the  spleen        .    71 
His  opinion  that  the  thymus  is  an  appendage 
to  the  lymphatic  system,  chyle  globules,  or 
the  corpuscles  of  the  thymus       .  .  72 

His  belief  in  the  existence  of  a  nucleus  in  the 
red  blood  disc  .  .  .  :    93 

Hodgkiii.     His  disbelief  in  the  existence  of  a 

nucleus  in  the  red  blood  disc       .  .  93 

Haematine  .  .  .  .  .  .95 

Hooke.    On  the  hair   .  .  :  .296 

Horner,  Professor:  On  the  axillary  glands  .  441 
Hunter.  On  the  persistence  of  fat  vesicles  .  261 
Huschke.   On  the  structure  of  the  kidney  .  450 


Inflammation.    Causes  of 

Exciting  cause    . 

Proximate  cause 
Injections.    Minute 

Objects  of 

Of  arteries 

Of  Veins 

Syringes  used  in 

By  Swammerdam's  Syringe 

By  Charriere's  ditto 

Materials  used  in        .  , 

With  turpentine 

With  ether      . 

By  double  decomposition 

Of  one  set  of  vessels 

With  gelatine 

With  fresh  milk         .  , 

Introduction  .  . 


140 

140 
140 
38 
38 
39 
411 
40 
40 
41 
42 
42 
43 
44 
48 
48 


PAGE 

Jacobi.    Experiments  in  fertilizing  the  ova  of  a 

carp  .....        234 

Japanner's  gold  size  .  .  .  .49 

Johnson,  Dr.  G.    On  fatty  degeneration  of  the 

kidney         ....  454,  407 

On  the  inflammatory  diseases  of  ditto  .  462 

Jones,  Mr.  Wharton.    On  the  presence  of  a  nu- 
cleus in  the  blood  disc  of  the  lamprey    . 

On  the  mulberry  or  granulated  appearance  of 
the  red  blood  disc        •  .  .  .94 

On  the  structure  of  the  red  blood  corpuscle        95 

Opinions  concerning  the  white  blood  corpuscle  111 

Observation  on  the  blood  corpuscle,  consider- 
ed in  its  different  phases  of  development  in 
the  animal  series    . 

On  the  nuclei  of  mucous  corpuscles     . 

On  the  brown  pigment  of  the  membranous 
labyrinth  of  the  ear  of  man  .  .        287 

On  the  tubular  character  of  the  gelatinous 
nerve  filaments  ....  382 

On  the  structure  of  the  ganglion  caecum  in  the 

dog 382 

Jones,  Dr.  Handfield.   Reasons  for  his  non-belief 
in  the  existence  of  a  lobular  biliary  plexus 

His  investigations  as  to  the  terminations  of  the 
biliary  ducts 

On  the  arrangement  of  the  hepatic  cells  in 
connexion  with  secretion 

On  the  union  and  consolidation  of  the  hepatic 
cells  .... 

Description  of  the  active  and  passive  condi- 
tions of  the  lobules  of  the  liver  - 

Ou  the  development  of  the  liver     . 

On  the  calculi  of  the  prostate    . 

On  the  peculiar  corpuscles  in  the  spleen 

On  the  epithelium  of  the  villi   . 

On  the  granular  substratum  in  ditto 

On  oil  drops  in  ditto 


9J 


116 
175 


425 

426 

427 

427 

428 
434 
437 
491 
493 
494 
494 


Kidney.     Secreting  apparatus  of        .  .        442 

Tubes  of   .  .  .  .  .  .442 

Tubes  of,  in  cortical  part       .  .  .        442 

Tubes  of,  in  medullary  part       .  .  .  442 

Basement  membrane  of  .  .        443 

Frame-work  for  the  lodgment  of  tubes  .  443 

Malpighian  dilatations  .  .  .        443 

Vessels  of  .  .  .  .  .443 

Capsules  of     .  .  .  .  .        444 

Epithelium  of  the  tubes  .  .  .  444 

Ditto  of  Malpighian  dilatations       .  .        444 

Ditto  of  neck  of  Malpighian  dilatations  .  444 

Vascular  apparatus  of  kidney         .  .        444 

Renal  artery         .  .  .  .  .444 

Renal  vein      .....        445 

Inter-tubular  plexus        ....  445 

Portal  vein     .....        445 

Portal  system       .  .  .  .  .445 

Afferent  vessel  of  Malpighian  tuft  .        445 

Efferent  vessel  of  Malpighian  plexus    .  .  445 

Malpighian  body,  structure  of,  when  complete  447 
Malpighian  bodies  of  birds  and  reptiles  .  448 

Size  of  .....        448 

In  elephant  and  birds     ....  448 

Development  of  the  kidney   .  .  .        449 

True  capsule  of  the  Malpighian  tuft     .  .  452 

Pathology  of  the  kidney        .  .  .        453 

To  inject   .  .  .  .  .  .482 

Kiernan.     His  description  of  the  biliary  ducts, 
and  of  the  lobular  biliary  plexus  .        424 

On  the  acini   of  the  liver  .  .  .  424 

Kieser.   On  the  pigmentary  membrane  of  the  eye  286 

Kolliker.    On  the  absence  of  internal  organs  in 

spermatozoa     .....  225 

On  the  development  of  spermatozoa  .        231 

On  non-striated  muscle  ....  371 

On  the  structure  of  the  kidney        .  .        450 


Labial  glands 

Labelling  slides,  method  of 

Lachrymal  fluid 


419 

63 

250 


INDEX, 


555 


PAGE 

Lachrymal  glands  ....        423 

Lacteal  or  Mesenteric  glands         .  .  .  4l»ii 

Lactoscope         .  .  .  •  .211 

LaUemand.  On  the  development  of  spermatozoa  230 
Lambotte.    His  disbelief  in  the  existence  of  a 

nucleus  in  the  red  blood  disc       .  .  93 

Lamina  fusca,  pigment  cells  of    .  .  •  288 

Lampenhoff.    On  living  semen  in  the  vesicular 

seminales  of  dead  men     .  .  '  227 

Lamprey.    Blood  of  .  .  .  .91 

Lane,  Mr.    Analysis  of  chyle  .  .  68 

On  blood  discs  in  the  chyle        .  .  .71 

His  belief  in  the  existence  of  a  nucleus  in  the 

red  blood  disc         ....  93 

Views  on  the  structure  of  the  red  blood  cor- 
puscle .  .  .  .  .95 
Llama.    Blood  of                     ...         91 
Lealand  and  Powell.    Microscope  of      .  .    29 
Letheby,  Dr.  H.    On  cell-like  bodies  in  the  bile    243 
On  the  calculi  of  the  prostate    .            .  .  437 
Leeuwenhbek.    The  first  to  describe  the  blood 
globules  in  different  animals         .           .  89 
The  discoverer  of  milk  globules           .           .  197 
His  discovery  of  living  spermatozoa  in  the 
uterus  and  Fallopian  tubes  of  a  bitch,  seven 
days  after  connexion          .           .            227, 233 
On  the  discovery  of  spermatozoa         .            .  218 
On  the  spermatozoa  of  the  ram  and  rabbit        223 
The  discoverer  of  epithelium  cells  in  the  mu- 
cus of  the  vagina         ... 
The  first  to  observe  that  the    epidermis  was 
composed  of  scales            .            .            .        277 

On  the  hair 296 

Lenticular  glands  ....        420 

Liebig.    On  the  condition  of  iron  in  the  blood       98 
Liq.  potass.,  action  of,  on  pus  .  10G,  188 

Liston,  Mr.    His  disbelief  in  the  existence  of  a 


264 


nucleus  in  the  red  blood  disc 
Lingual  glands  .... 
Liver  ...... 

Secreting  apparatus  of 

Lobules  of  ...-  • 

Form  of  .... 

Size  of      ..... 

Union  of  .... 

Inter-lobular  fissures       .... 

[nter-lobular  spaces  .... 

Follicles,  or  acini  .... 

Biliary  ducts  ..... 

Lobular  biliary  plexus    .... 

Doubts  concerning     .... 

Mode  of  termination  of  .  . 

Structure  of    . 

Secreting  cells     ..... 

Structure  of    . 

Linear  and  radiated  disposition  of 

Union  of         ....  . 

First  secretion  of  bile  in  central  cells  . 

Active  and  passive  conditions  of  the  lobules 
of  the  liver  .... 

Dissolution  of  membrane  of 

Gall  bladder   ..... 

Structure  of         .... 

Vascular  apparatus  of  liver 

Hepatic  veins       . 

Central-lobular  veins 

Sub-lobular  veins  . 

Portal  veins    . 

Inter-lobular  veins  . 

Lobular  capillary  plexus 

Hepatic  artery      . 

Pathology  of  liver      .  .  .  • 

Development  of  . 

Prostate  gland  .... 

Structure  of  .  •  • 

Epithelium  of  . 

Calculi  of  . 

Increase  of  in  old  age 

Injection  of  .... 

Locus  Niger.    Ganglion  cells  of 


93 
419 
423 

424 
424 
424 
424 
424 
424 
424 
424 
424 
425 
425 
426 
426 
426 
427 
427 
4-27 
4-27 

428 
429 
429 
429 
4'.I0 
430 
430 
430 
430 
430 
431) 
431 
432 
434 
436 
436 
436 
436 
43l> 
435 
377 


PAGE 

.  395 

395 
.  396 

396 
.  397 

396 
.  396 

397 
.  397 

398 
.  398 

398 
.  398 

398 

.  398 

the  air  cells  of      404 

.  404 

405 

.    76 

77 

.  492 

67 

.    68 

68 

.    69 

69 


Lungs.     Jleriferous  apparatus  of 

Bronchial  tubes 

Air  cells    . 

Form  of 

Size  of 

Structure 

Communications  of 

Models  of 

Epithelium  of 

Vascular  apparatus  of 

Arteries    . 

Veins   . 

Capillaries 

Natural  inflation  of  lungs 

Artificial  ditto 

Mr.  Rainey  on  epithelium  in 

Of  birds   . 

Injection  of     . 
Lymphatics.    Structure  of 

Valves  in 
Lymphatic  glands.    Structure 
Lymph    . 

Analysis  of 

Coagulum  of  . 

Granular  corpuscles  of    . 

Serum  of 

Examination  of   . 
Lymphatic  system.    Structure  of  lymphatics         67 

Ditto  of  lacteals   .  .  .  .  .68 

Ditto  of  lymphatic  glands    .  .  .        492 

Ditto  of  mesenteric  glands         .  .  .  492 

Thoracic  duct  .  .  .  .  6S 

Blood  in  lymphatics  of  spleen  .  .  .70 

Madder.    In  bones  of  animals  fed  with  .        324 

Magendie.     His  disbelief  in  the  existence  of  a 

nucleus  in  the  red  blood  disc  .  .    93 

Experiments  of,  on  the  blood  .  .        153 

Malpighi.    The  discoverer  of  the  red  globule         88 

Mammary  Glands.    Structure  of         .  .        423 

Efferent  ducts  of  .  .  .  .423 

Milk  globules  in  follicles  of  .  .        423 

Follicles  of  .  .  .  .423 

Existence  of  mammary  gland  in  the  human 

male 423 

Epithelium  of  .  .  .  423 

Degeneration  of  mammary  glands  in  age  .        423 

Lacteals  of 423 

Man.     Spermatozoa  of  ...        219 

Mandl.     On  the  blood  of  the  dromedary  and 
alpaco    .  .  •  •  •  .90 

His  belief  in  the  existence  of  a  nucleus  in  the 
red  blood  disc         ....  93 

His  opinion  that  the  formation  of  the  nucleus 
of  the  blood  corpuscles  of  reptiles  takes 
place  subsequently  to  the  removal  of  the 
blood  from  the  system  •  .  .  124 

Opinion  as  to  the  nature  of  pus  and  mucous 
globules       .....        186 

Opinion  as  to  the  structure  of  milk  globules     197 
On  the  structure  of  the  fat  vesicle   .  .        257 

On  stellate  bodies  observed  in  decomposing 
fat  vesicles         .  .  .  .  .259 

Marine  glue        .....  50 

Martin.     Structure  of  hair  of        .  .  .304 

Materials  used  in  injections      ...  42 

Mayer,  E.  H.    On  the  nature  of  bone  cells         .  330 
Medulla  Oblongata.    Ganglion  cells  of  .        377 

Menobranchus.    Bone  cells  of  .  .  321 

Meibomian  glands         .  .  .  .        416 

Number  of  ....  416 

Form  of  .  .  .  .416 

Structure  of  .  .  •  .416 

Meckauer.    On  the  structure  of  cartilage      .       311 
Microscope.    Of  Allen       .  .  .  .33 

Brunner  .....         31 

Chevalier      .       .  .  .  .  .30 

Oberhauser     .....         30 

Pike  &  Sons 33 

Powell  &  Lealand     ....         29 


556 


INDEX 


PAQE 

Microscopes.    Of  Ross       .  .  .  .29 

Smith  &  Beck  ....         30 

Spencer     .  .  .  ,  .  .31 

Microtome  .  ...  34 

Milk.     Inorganic  components  of  .  .  195 

Organic  constituents  of  195 

Analysis  of  ...  209, 211 

Serum  of  .  .  .  .196 

Cheese  globules  of  .  .  .  .  196 

Fatty  ditto  of  ....        197 

Form,  size  and  structure  of  .  .  197 

Opinions  of  observers  as  to  the  structure  of      197 
Action  of  boiling  water,  boiling  alcohol,  the 

alkalies,  acetic  acid,  and  asther  on  .        200 

Colostrum  of  .  .  .  .  201 

Pathology  of  milk      ....        203 
Milk  of  unmarried  women        .  .  .  206 

Ditto  of  women  previous  to  confinement   .        206 
Ditto  of  women  who  have  been  delivered,  but 

who  have  not  nursed  their  offspring  .  208 

Milk  in  the  breasts  of  children        .  .        208 

Different  kinds  of  milk  ....  208 
Relative  proportions  of  the  elements  of  milk 

in  woman,  the  cow,  the  goat,  and  the  ass      209 
Good  milk  .....  210 

Poor  milk        .....        212 
Rich  milk  .....  213 

Adulteration  of  milk  .  .  .        213 

Formation  of  butter        ....  214 
Milk  abandoned  to  itself      .  .  .        215 

Penicillum  glaucum  in    .  .  .  .  216 

Medicines  in  milk     ....        217 
Injections  with  milk       .  .  .  .48 

Mitscherlich.    Observations  on  the  saliva  241 

Mondini.    On  the  pigment  of  the  eye  .        286 

Mounting  objects.     Method   of    .  .  .56 

The  dry  way  .....  59 

In  Canada  balsam  with  heat      .  .  .60 

As  opaque      .....         63 

Mouse.    Spermatozoa  of   .  .  .  .  219 

Structure  of  hair  of  .  .  .  .        304 

Mucus.    General  characters  of     .  .  .  171 

Ditto  of  true,  false,  and  mixed  membranes         172 
Corpuscles  of  ....  174 

Mucus  of  different  organs     .  .  .        179 

Vaginal  and  uterine  ditto  .  .  .180 

Effect  of  acid  mucus  on  the  teeth    .  .        180 

Tricho-monas  in  vaginal  mucus  .  .  181 

Vibrios  in  ditto  ....         182 

Distinctive  characters  of  mucous  and  pus       .  186 

Mucous  Membranes.    True  or  compound  172 

False  or  simple  and  mixed  .  172,  418 

Compound.      Alimentary  canal  from  cardia 

downwards       .....  419 
Gall-bladder,  oesophagus,  vagina  .        419 

Neck  of  uterus,  vesiculae  seminalis      .  .  419 

Simple.    Eustachian  tubes    .  .  .        419 

Trachea,  bronchial  tubes,  and  bladder  419 

Unimpregnated  uterus    ....  419 
Mixed.    Mouth  and  nose     .  .  .        419 

Mucous  Glands.    Structure  of  .  .  420 

Follicles,  epithelium,  and  membrane  of      420,  421 

Muller.    On  blood  discs  in  the  chyle  .  .  71 

On  the  quantity  of  blood  in  the  system  .    80 

On  the  coagulation  of  blood  after  freezing  81 

On  the  blood  of  the  frog  .  .  .82 

His  belief  in  the  existence  of  a  nucleus  in  the 

red  blood  disc         ....  93 

His  verification  of  the  white  globules  in  the 

blood  of  a  frog  .  .  .  .100 

On  spermatozoa         ....        223 
On  the  terminations  of  nerves  in  the  mem- 

brana  nictitans  ....  385 

On  the  kidney  ....        450 

Muscle.    Voluntary  ....  354 

Involuntary     .....        354 
Of  animal  and  organic  life         .  .  .  354 

Striped  and  unstriped  .  .  .        354 

General  structure  of  muscle      .  .  .  355 

Of  unstriped  muscular  fibrilla         .  .        355 


Muscle.    Nuclei  of  unstriped  fibrilla 

Muscular  structure  of  the  heart 

Of  striped  muscular  fibre  .  . 

Size  and  form  of 

Size  of,  in  foetus  and  adult       .  . 

Cause  of  striation  of 

Differences  of  opinion  as  to 

Lacerti,  or  bundles  of  fibres 

Structure  of  fibrillar  of  fibres     . 

Nuclei  of        ...  . 

Situation  of,  in  the  fibre  .  . 

Sarcolemma 

Cleavage  of  fibre  .  . 

Blood-vessels  of  muscles 

Nerves  of  ditto     .... 

Union  of  muscle  with  tendon  . 

Muscular  contraction 

Active  and  passive  contraction  of  muscle 

Zigzag  disposition  of  the  fibres  in    . 

Approximation  of  the  strife  in 

Increase  in  the  diameter  of  the  fibre  in 

Rigor  Mortis        .... 

Muscular  sound 

Developments  of  muscle,  three  stages  of 

Differences  of  opinion  as  to  striation 

Kolliker.    On  non-striated  variety  of   . 

Examination  of 
Muscular  rigidity.    A  sign  of  death 
Musk  Deer.    Structure  of  hair  of 


PAGE 

.  3.j.) 
356 

.  357 
357 

.  357 
358 

.  358 

357 

358,  547 

359 

.  :^9 
355,  359 

.  361 
355,  301 

.  361 
362 
363 
303 
363 
365 
365 
366 
366 
367 
358 
371 
375 
87 
304 


Nachet.    Microscope  of  .  31 

Nails.    Structure  of  .  .  .  .282 

Development  and  Pathology  of     .  .  283,  284 

Modification  of  in  the  animal  kingdom      .        285 
Regeneration  and  Examination  of       .  .  285 

Mr.  Rainey  on  the  structure  and  formation  of  541 
Naphtha       .  .  .  .  .  .58 

Napu  Musk  Deer.    Blood  of   .  .  .92 

Nasmyth  Mr.    On  the  constitution  of  the  inter- 
tubular  substance  of  dentine  .  .  337 
On  secondary  dentine           .           .           .        337 
His  opinion  that  the  cementum  passes  over  the 

entire  surface  of  the  enamel  of  the  tooth  338, 344 
On  the  development  of  dentine  .  .  341 

Nasse,  Professor.    On  the  adherence  of  the  red 
corpuscles  in  rolls  84 

On  a  mottled  appearance  characteristic  of  in- 
flammatory blood        .  .  .  .85 

His  opinion  that  the  white  globules  are  red 

blood  corpuscles  in  process  of  formation        112 
On  the  milk  globules      ....  200 

On  the  speedy  disappearance  of  colostrum 
corpuscles  in  women  who  have  borne  many 
children       .....        203 

Needles.    Dissecting  .  .  .  .35 

Nerves.    Cerebro-spinal  system  .  .        376 

Sympathetic  ditto  ....  380 

Structure  of  nerves    ....        376 

Of  cerebrospinal  system  .  .  .  376 

Secreting,  or  cellular  structure  of    .  .        376 

Disposition  of  .  .  .  .  376 

Granular  base  and  cells  of    .  .  .        376 

Caudate  ganglion  cells  and  distribution  of       .  377 
Globular  ganglion  cells.    Distribution  of    .        378 
Of  the  tubular  struct ure  .  .  .  378 

Of  the  cerebrum  and  nerves  of  special  sense    378 
Of  cerebellum  and  spinal  cord       .  .        378 

Of  posterior  root  of  spinal  nerves        .  .  378 

Of  sympathetic  system  and  motor  nerves  378 

Varicose  dilatation  of  the  tubes      .  .        378 

White  substance  of  Schwann  in  .  .  379 

Neurilemma   .....        379 

Axis  cylinder       .....  380 

Globules  of  white  substance  of  brain         .        380 
Ditto  of  spinal  marrow,  and  nerves  of  special 
sense     .  .  .  .  .  .380 

Of  sympathetic  system  .  .  .        38.) 

Structure  of  nerves  of    .  .  .  .  360 

Gelatinous  nerve  fibres  of    .  .  .        380 

Where  best  seen  ....  3dl 


557 


PAGE 

Nerves    Proportion  of  nerve  fibres  in  different     381 
Structure  of  ganglia  .  .  .        381 

Tubular  and  gelatinous  nerve  fibres  in  .  383 

Arrangement  of  ....  383 
Ganglion  globules  and  nerve  fibres  in  .  .  384 

Origin  and  termination  of  nerves    .  .        384 

Origin  in  loops  .....  384 
In  ganglion  cells  ....  385 
Termination  in  loops       .  .  .  385 

In  definite  extremities  .  .  .        386 

Blood-vessels  of  nerves  .  .  .  384 

Pacinian  bodies  ....         386 

Development  of  nerve  fibres     .  .  .  388 

Ditto  of  ganglionary  cells     .  .  .        389 

Regeneration  of  nervous  matter  .  .  390 

Researches  of  M.  Robin        .  .  29 1 

Examination  of    .  .  .  .  .  394 

Nesbitt.    The  first  to  distinguish  between  the 

two  forms  of  ossification  .  .  .        325 

Neurilemma  .....  379 

Nipple,  glands  of  .  .  .418 

Nose.      Structure  of  mucous    membrano  of. 

See  Smell         .....  505 
Nutrition,  corpuscular  theory  of  .  99,  108 

Oberhauser.    Microscope  of  .  .30 

Objects  of  minute  injections    ...  38 

Oesophagus.      Muscular  fibres  of,  striped    and 
unstriped  .....  360 

Omnivora.    Blood  of    .  .  .  .92 

Opaque  objects.    Methods  of  mounting  .    63 

Organs  of  ihe  senses.    Touch  .  .        497 

Taste         .  .  .  .  .  .501 

Smell  and  Vision       ....        505 

Hearing    .  .  .  .  .  .523 

Owen,  Mr.    His  disbelief  in  the  existence  of  a 
nucleus  in  the  red  blood  disc  .  .    93 

On  the  development  of  dentine       .  .        341 

Pacini.    On  the  Pacinian  bodies  .  .  .  386 

Pacinian  bodies.    Situation  and  structure  of        386 

Inner  system  of  capsules  of  .  .        387 

Termination  of  nerve  in  .  .  .  387 

Inter-capsular  ligament  of    .  .  .        387 

Varieties  in  form  and  structure  of         .  .  388 

Pacchionian  glands.    Situations  and  forms  of       538 

Palatine  glands  ....        419 

Palmipedes.    Spermatozoa  of  .  .  220 

Pancreatic  fluid  ....        250 

Papillae  of  skin        .....  498 

Examination  of  ...  .        500 

Pappenheim.    On  the  structure  of  the  kidney      451 

Passeres.     Spermatozoa  of  .  .        219 

Pathology.     Of  the  blood  .  .       '     . x        .142 

Of  the  red  corpuscle  .  .  .        142 

Increase  of  in  plethora  ....  143 

Decrease  of  in  anaemia         .  .  .        144 

Increase  of,  under  the  influence  of  recovery 

and  certain  medicinal  agents  .  .  146 

Effects  of  disease  on  the  white  corpuscles  .        146 
Deficiency  of  fibrin  in  fevers,  typhus,  small- 
pox, scarlatina,  and  measles  .  .  .  147 
Increase  of  fibrin  in  inflammatory  affections, 
as  pneumonia,  plueritis,  peritonitis,  acute 
rheumatism             ....        148 
Condition  of  the  blood  in  hemorrhages  .  151 
Decrease  in  the  normal  portion  of  albumen        154 
Becquerel  and  Rodier's  pathological  researches 

on  the  blood     .....  158 

Blood  in  ecchymoses  .  .  .        161 

Of  milk.     Persistence  of,   in  the  condition  of 

colostrum         .....  203 

Recurrence  of  colostrum      .  .  .        204 

Influence  of  retention  of  milk  .  .  204 

Pus  and  blood  in  milk  .  .  .        205 

The  milk  of  syphilitic  women  .  .  .  206 

The  milk  of  women  in  case  of  the  premature 

return  of  the  natural  epochs         .  .        206 

Of  the  semen  .....  234 

Of  the  urine      .....        246 


PAGE 

Pathology.    Of  albuminous  urine  .  .  247 

Fibrinous,  fatty,  chylous,  and  milky  ditto  248 

Excess  of  mucus  in  ditto     .  .  .        249 

Blood  in  ditto       .  .  .  .  .249 

Pus  in  ditto    .....        250 

Of  epidermis  .....  278 

Of  nails  .....        284 

Of  pigment  cells      .....  286 

Of  cartilage        .  .  .  .  .311 

Of  the  lungs.    Emphysema  .  .  .  399 

.    Asthma  and  pulmonary  apoplexy  .  .        400 

Pneumonia  and  tubercles  .  .  .  401 

Of  liver.     Secreting  apparatus  .  .         432 

Biliary  and  fatty  engorgement  of  cells  .  432 

Vascular   apparatus.      Anaemic  condition  of 

lobules 433 

First  stage  of  hepatic  venous  congestion  .  433 
Second  stage  of  ditto  ....  433 
Nutmeg  or  dram-drinker's  liver       .  .        433 

Portal  venous  congestion  .  .  .  433 

Hydatids  and  cysts  in  liver  .  .  .        434 

Of  the  bile  .  .  .  .  .433 

Of  kidney.     Fatty  condition  of  .  .  452,  467 

Pathology  of  "Blight's  disease,"  according  to 

Toynbee  .....  455 
Sub-acute  inflammation  of  the  kidney  .  457 

Cystic  disease  of  ditto  .  .  458,  465 

Inflammatory  diseases  of  the  kidney    .  .  462 

Acute  desquamative  nephritis         .  .        463 

Chronic  ditto  .....  464 
First  and  second  form  of  fatty  degeneration  467 
Exudation,  and  ditto  within  the  tubes  .  469 

a.  Crystalline  or  saline  deposits  .  .        460 

b.  Oleo-albuminous  exudation  .  .  470 

c.  Exudations  in  the  form  of  pus  .  470 
Exudation  within  the  Malpighian  bodies  .  470 
Exudation  in  the  inter-tubular  tissue  .  470 
Partial  distribution   of  the  oleo-albuminous 

exudation  .  .  .  ...  470 

Lesions  affecting  chiefly  the  vascular  system     471 
Congestion  followed   by  permanent    oblitera- 
tion of  capillaries  of  cortical  substance  472 
Waxy  degeneration   ....        472 

Lesions  of  the  tubes  and  epithelium    .  .  474 

Imperfect  development  of  cells  and  nuclei        474 
Desquamation  of  the  epithelium  .  .  474 

Obliteration  of  the  tubes      .  .  .        475 

Microscopic  cyst  formation        .  .  .  476 

Dilatation  and  thickening  of  the  tubes       .        478 
Conclusion  .....  479 

Of  thyroid  gland.    Condition  of,  in  goitre    .        488 
Paint  injections         .  .    -42 

Peyen.     His  analysis  of  the  milk  of  woman  209 

Pearson.     On  the  colouring  matter  of  the  lungs 

and  bronchial  glands  .  .  .  287 

Peligot,  M.    His  observations  on  milk  retained 

for  a  long  time  in  the  breast         .  .        204 

Peyer's  glands         .....  414 

Pharyngeal  glands         .  .  .  .419 

Pia  mater.    Structure  of    .  .  .  .  537 

Choroid  plexuses  and  velum  inter-positum  of    538 


Villi,  blood-vessels,  and  epithelium  of 

.  538 

Pig.    Fat  vesicles  of     . 

254 

Bulb  of  hair  of    . 

304 

Pigment  Cells.    Structure  and  situation  of 

286 

Pathology  of  and  freckles 

.  287 

Cells  of  the  choroid   . 

288 

Of  the  iris  and  ciliary  processes 

.  288 

Of  the  lamina  fusca  . 

288 

Pigment  cells  in  the  skin 

.  289 

Ditto  of  outer  surface  of  choroid    . 

289 

Pigment  granules 

.  289 

Examination  of                     .            . 

290 

Pike  and  Sons.     Microscope  of    . 

.    33 

Pineal  Gland.    Caudate  cells  of 

536 

Compound  and  calcareous  cells  of 

.  536 

Earthy  matter  of 

536 

Blood-vessels  and  nerve  tubules  of 

.  537 

Pipettes              .... 

37 

Pituitary  gland.     Lobes  of           .           . 

.  535 

558 


INDEX, 


PAGE 

Pit'y  glands.   Stracture  and  infundibuJum  of        535 
Comparison  of,  to  a  ganglion    .  .  .  535 

Porcupine.     Bulb  of  spines  of  .  .        304 

Powell  and  Lealand.    Microscope  of  .29 

Preparation  of  objects  ....  37 

Prepuce,  glands  of  ....  418 

Preservation  of  objects  ...  49 

Prevost  and  Dumas.    Their  observations  of  liv- 
ing spermatozoa  seven  days  after  connexion    233 
Experiments  on  the  semen        .  .  .  234 

Proteus.     Blood  globules  of    .  .  .123 

Shape  of  bone  cells  of   .  .  .  .321 

Purkinje.     On  the  vibratile  epithelium  of  the 
ventricles     .....        271 

Purkinje  and  Valentin.     On  ciliary  motion    269,  270 

Pus.    General  characters  of     .  .  .        183 

Distinctive  characters  of  pus  and  mucus         .  186 

Action  of  liq  potass,  and  sol.  amon.  on  pus  106,188 

Distinctions  between  certain  forms  of  pus  and 

mucus    ......  190 

Detection  of  pus  in  blood    .  .  ly  1 

False  pus  .....  192 

Metastatic  abscesses  ....        193 

Quekett   Mr.    His  disbelief  in  the  existence  of 
a  nucleus  in  the  red  blood  disc         .  .    93 

His  opinion  on  the  mammillated  appearance 

of  the  red  blood  disc         .  .  .        139 

On  bone  cells       .....  322 
On  the  calculi  of  the  prostate  .  .        437 

On  looped  blood-vessels  in  the  olfactory  re- 
gion of  the  fcetus         ....  508 
Quevenne,  M.    On  the  cheese  globules  .        196 

On  the  milk  ditto  ....  200 

Rainey,  Mr.     On  epidermis    .  .  .281 

On  the  structure  and  formation  of  the  nails      541 
On  the  ganglionic  character  of  the  arachnoid 

membrane  of  the  brain  and  spinal  marrow  543 
On  healthy  air  cells  ....  397 
On  sudoriparous  glands        .  .  .        439 

On  lungs  of  birds  ....  404 

On  the  structure  of  the  sudoriferous  glands       547 
On  the  synovial  fringes  ....  247 


Ram.    Spermatozoa  of  223 

Rapaces.     Spermatozoa  of  220 

Rapp.    On  nerves  in  the  bulb  of  the  hair  of  the 

seal,  porcupine,  &c.  .  .  .        304 

Rat.     Spermatozoa  of  .  .  .  223 

Rees,  Dr.  G.  O.    Analysis  of  lymph    .  .        68 

His   belief  in  the  existence  of  a  nucleus  in 

the  red  blood  disc        .  .  .  .93 

On  the  structure  of  the  red  blood  corpuscle         95 

On  the  urine  of  persons  taking  cubebs,  &cc.     247 

Reichart.    On  the  kidney        .  .  .450 

Reptilia.    Blood  globules,  form  and  size  of       .  123 

Structure  of    .  .  .  .  .        124 

Action  of  water  on         ...  .  124 

Ditto  of  acetic  acid  on         .  ,  125 

White  globules  of  .  .  .125 

Plastic  properties  of  red  ditto  .  .        125 

Fat  of  reptiles      .....  255 

Malpighian  bodies  of  426 

Respiration.    Corpuscular  theory  of  .99 

Rhinorceros.    Blood  of  ...         92 

Rigor  Mortis  .....  366 

Robin,  M.  C.   Researches  on  the  nervous  system  391 

On  the  axillary  glands    ....  441 

Rodentia.    Hair  of  .  .  .        304 

Ross.    Microscope  of  .  .  .29 

Sable.    On  the  medullary  canal  of  hair  of  296 

Ou  the  structure  of  the  hair  of             .  .  304  I 

Salamander.     Spermatozoa  of            .  .        223 

Saliva.    Amount  of            ...  .  241 

Mitscherlich's  observations  on        .  .        241 

Solid  constituents  and  salts  of  .           .  .  241 

Acetic  acid  in            ....  241 

Admixture  of  saliva  with  mucus         .  .  241 

Uses  of           ....  242 


PAGE 

.  422 
422 

.  57 
355 

.  33 
223 


Salivary  Glands.    Stracture  of     . 

Follicles  and  form  of,  in  embryo     . 
Salt  and  water 
Sarcolemma       .... 

Scalpels  for  dissection 
Scansores.    Spermatozoa  of    . 
Scarpa.     On  the   presence  of  pigment  in  the 
membranous  labyrinth  of  the  ear  of  Mam- 
malia    ......  287 

Scherer.    On  pigment  cells  in  the  bile  .        243 

Schuliz.    Observations  on  the  action  of  oxygen 
and  carbonic  acid  on  the  form  of  the  blood 
corpuscles        ....        136, 137 

Ditto  of  iodine  on  ditto         .  .  .163 

Schumlansky.    On  the  structure  of  the  kidney    450 

Schwann.    On  the  membrane  of  the  fat  vesicle   256 

On  the  nuclei  of  the  fat  vesicle  .  .  256 

On  the  motion  of  the  pigmentary  granules  in 

the  cells  of  the  choroid     .  .  .        288 

On  the  membrane  lining  the  cavities  of  true 
cartilage  .....  307 

On  Ihe  nature  of  bone  cells  .  .        330 

On  the  tubular  nerve  fibre  in  the  early  stages 
of  its  development      ....  382 

Sebaceous  glands.  ....        414 

Distribution,  secretion,  and  cells  of      .  .  415 

Structure  of    ...  .  416 

Sequin.    On  the  amount  of  fluid  passing  off  by 
the  skin        .....        243 

Semen.    Characters  of  .  .  .  218 

Spermatozoa  ....        218 

Pathology  of  semen        .  .        "  .  .  234 

Application  of  a  microscopical  examination 
of  the  semen  to  legal  medicine    .  .        237 

Sharpey,  Dr.    On  the  structure  of  the  lamella  of 
bone      .  .  .  .  .  .320 

On  infra-membranous  ossification  .  .        325 

On  the  striated  muscular  fibrilla  .  .  358 

Sidall.    On  the  increased  quantities  of  white  cor- 
puscles in  the  blood  of  the  horse  in  influenza  109 
Siebold.    On  the  absence  of  internal  organs  in 
the  spermatozoa  ....  225 

On  the  development  of  spermatozoa  .        230 

On  living  ditto  in  the  uterus  and  fallopian 

tubes  eight  days  after  connexion       .  .  233 

Simon,   M.      Organic    constituents   of  human 

milk,  according  to  .  .  .  195,  209 

Analysis  of  sweat  ....  244 

Simon,  Mr.     On  the  thymus  .  73,  485,  486 

On  sub-acute  inflammation  of  the  kidney  457 

Siren.    Blood  globules  of 
Bone  cells  of 


Skey.    Qn  the  size  of  muscular  fibres  of 
heart  .... 

Skin.     See  Touch   .... 

Smell.     Structure  of  mucous  membrane 
nose  .... 

Tactile  region      .... 

Epidermis,  papillae,  and  hairs  of    . 

Sebaceous  glands  of 

Pituitary  region        .  .  . 

Epithelium,  and  mucous  follicles 

Blood-vessels  of 

Olfactory  region.    Position  of  . 

Characters,  epithelium,  and  glands  of 

Pigment  cells  and  blood-vessels  of 

Looped  ditto  of  in  foetus    . 

Gelatinous  nerve  filaments  of    . 

Olfactory  lobes  and  filaments 
Smith  and  Beck.    Microscope  of 
Spallanzani.    The  discoverer  of  the  white 
bules  in  the  blood  of  salamanders 


123 

321 

he 

356 
.  497 
of 

505 
.  506 

506 
.  506 

506 
.  505 

506 
.  506 

507 
.  508 

508 
.  508 

508 
.    30 


100 


Experiments  on  frogs  with  spermatized  water  234 
Spencer.    Microscope  of  .  .31 

Spermatophori        .....  228 
Spermatozoa      .....        218 

Form  of  (in  man,  the  rat,  the  mouse,  guinea- 
pig,  in  birds,  tritons,  and  salamanders;        .  219 

Size  and  structure  of     .  .  .        220, 221 

Motions  and  mode  of  progression  of    .  .  225 


INDEX. 


559 


PAGE 

Spermatozoa.    Duration  of  motion    .  .        22G 

Effects  of  reagents  on     .  .  .  .  227 

Development  of         ....       229 
Spermatoaoa  essential  to  fertility         .  .232 

Condition  of,  iu  hybrids        .  .  .        233 

Spinal  Chord,  ganglion  cells  of     .  .  .  377 

Spleen.    Structure  and  capsule  of      .  .        489 

Blood-vessels  and  secreting  structure  of  .  489 

Dr.  Jullien  Evans  on  ...        489 

Dr.  Jones  on        ....  .  491 

Peculiar  corpuscles  in  491 

Lymphatics  of  .  .  .  .70 

Solids 253 

Fat 254 

Epithelium     .....        264 
Epidermis  .....  277 

Nails 282 

Pigiuent  cells       .....  286 

Hair 291 

Cartilages  .  .  .  .  .306 

Bone    ......        317 

Teeth         .  .  .  .  .  .335 

Cellular  or  fibrous  tissue       .  .  .        346 

Muscle 354 

Nerves  .....        376 

Glands      ......  406 

Solitary  Glands.    Distribution  and  structure  of    413 
Orifices  of  .  .  .  .  .413 

Follicles  of  Lieberkhiin        .  .  .        414 

Supra-renal  Capsule.    Structure  and  tubes  of       488 
Molecules,  granular  nuclei,  and  parent  cells  of  488 
Differences  in  medullary  and  cortical  portions    488 
Vascular  distribution  in  .  .        488 

Capsule  of  ....  489 

Steatozoon  Folliculorum  .  .  .        403 

Stomach  Tubes.    Arrangement  of  .  .  412 

Form,  structure,  and  epithelium  of  .        412 

Existence  of  in  the  duodenum  .  .  412 

Modification  of,  near  the  pylorus     .  .        412 

Sudoriferous  Glands  ....  437 

Distribution  and  structure  of  .  .        437 

Tubes  and  ducts  .  .  .  .438 

Secreting  cells,  number  of   .  .  .        438 

Mr  Rainey's  description  of  .  .  439 

Examination  of  ...  440 

Structure  of,  according  to  Mr.  Eainey  .  .  547 

Swammerdam's  syringe  ...  40 

Sweat.    Quantity  of  ...  .  243 

Scales  of  epidermis  in  244 

Solid  constituents  and  analysis  of         .  .  244 

Crystals  in  .  .  .  .        244 

Pathology  of  .  .  .  .245 

Synovial  Fringes  ....        547 

Syringes  used  iu  injections  .  .  .40 


Table  of  magnifying  powers    . 

Taste.  Structure  of  mucous  membrane  of 

Chorium  and  papilla?  of 

Simple  and  compound   . 

Filiform,  and  fungiform 

Variety  of  ditto,  and  calyciform 

Foramen  caecum 

Mucous  follicles  and  epithelium  of 

Filiform  appendages  of 

Gustatory  region  of 
Teeth.    General  structure  of    . 

Dentine     ..... 

Modifications  and  tubes  of    . 

Secondary  formation  of,  in  cavity  of  tooth 

Coustitution  of  .  .  .  . 

Ditto  of  inter-tubular  substance,  accordin 
Nasmyth  .... 

Ditto,  according  to  Henle 

Peculiar  globular  formation  in  .  . 

Cementum        .... 

Bone  cells,  and  Haversian  canals  of     . 

Hexagonal  and  granular  layers  of  . 

Dentinal  tubes  in 

Cementum  and  dentine,  modifications  of 
other  .... 


29 
501 
501 

.  501 
502,  503 

.  503 
503 
504 
5U4 
502 
335 
335 
336 
337 
337 

337 
337 
337 
337 
337 
337 
338 


PAGE 

Teeth.    Enamel.    Fibres  and  cells  of         .    338,  339 

Form  and  arrangement  of  ditto      .  .        339 

Pulp  of  tooth.     Structure  of  .  .  339 

Development  of  teeth.     General  particulars  of  339 

Formation  of  dentine  and  dentine  pulp  .  341 

Membrane  of  ditto,  Formation  of  enamel  342 

Enamel  pulp.    Cells  of  .  .  .  .342 

Formation  of  cementum  and  cementum  pulp    343 

Caries  of  the  teeth  ....  344 

Tartar  on  ditto  ....        345 

To  make  sections  of  .  .  .  345 

Testis.    Structure,  tubes,  and  cells  of  .        483 

Thoracic  duct  .  .  .  .  .68 

Fluid,  red  colour,  and  composition  of        .  70 

Blood  and  granular  corpuscles  in         .  70,  71 

Thymus.    Follicles  of  .  .  .  .484 

Structure  of         ....  .  485 

Limitary  membrane  and  lobular  arrangement  486 

Blood-vessels  and  reservoir  of  .  .  .  485 

Mucous  membrane  and  capsule  of  .  .        485 

Blood-vessels  in,  and  milky  fluid  of  follicles  of  485 

Granular  and  nucleated  cells  of    .  .     73. 485 

Thyroid.    Vesicles  of  486 

Structure,  lobules,  and  blood-vessels  of     .        487 

Nuclei  and  cells  of  ...  .  487 

Todd  and  Bowman,  Messrs.    On  two  forms  of 

Haversian  canals    .  .  .  .319 

Experiments  on  bone  cells,  suggested  by  322 

Their  opinion  that  the  nuclei  of  cartilage  cells 

become  developed  into  bone  cells  .        328 

On  the  granular  blastema  in  cancelli  of  bones  329 

330 
347 
356 
358 
359 
360 
363 
369 
379 


412 
420 


498 


each 


33S 


On  the  nature  of  bone  cells 

On  the  structure  of  white  fibrous  tissue 

On  the  muscular  structure  of  the  heart 

On  "  sarcous  elements  "  .  . 

On  the  nuclei  of  striated  muscular  fibre 

On  the  striated  muscular  fibre  . 

On  muscular  contraction      .  . 

On  the  development  of  muscle 

On  the  neurolemma 

On  the  occurrence  of  gelatinous  fibres  in  parts 

where  their  nervous  character  is  indubitable  382 
On  the  termination  of  nerves  in  loops  in  the 

papillae  of  the  skin  and  tongue   .  .        385 

On  the  epithelium  of  the  stomach  cells  .  411 

On  a  modification  of  the  follicles  and  stomach 

tubes  near  the  pylorus 
Opinions  as  to  the  mucous  glands 
On  the  termination  of  the  nerve  tubules  in  the 

papilla;  of  the  tongue 
On  a  fibrous  structure  in  the  papilla?  of  tongue  498 
On  the  olfactory  region         .  .  .        506 

On  the  olfactory  filaments  .  .  .  508 

On  the  tubular  structure  of  the  cornea  proper  512 
On  the  anterior  elastic  lamina  of  cornea  .  513 
On  the  membrana  pupillaris     .  .  .  518 

On  certain  elastic  fibres  attached  to  the  pos- 
terior elastic  lamina         .  .  .        518 
On  the  granular  layer  of  the  retina     .  .  519 
On  a  layer  of  cells  situated  on  the  hyaloid 
membrane  .....        521 

Tomes,  Mr.    On  the  development  of  bone        .  328 
H  is  lectures  on  teeth  .  .  .        336 

Description  of  granular  layer  of  cementum  337 
On  the  development  of  dentine  .  .  341 

On  the  cells  of  the  cementum  pulp  .        343 

On  the  spaces  between  the  fibres  of  newly- 
formed  enamel  ....  343 
On  tubes  of  carious  dentine  .  .        345 

Tongue.     Structure  of.    See  Taste  .  .  501 

Ditto  of  frog   .....        126 

Tonsillitic  glands     .....  419 

Touch.    Seat  of  .  .  .  .497 

Papillae  of  .  .  .  .  .497 

Epidermis  of  .  .  .  .  .        499 

Distribution  and  arrangement  of  .  .  497 

Structure  and  basement  membrane  of  .  498 
Nuclear  contents  of  .  .  .  498 

Blood-vessels  of  ...        499 

Nerves  of  and  fibres'  in  498 


>00 


INDEX, 


Toynbee.    Oh  the  structure  of  Malpighian  body  453 
Oq  the  corpus  Malpighianum 
On  the  pathology  of  "  Bright's  disease" 
Tracheal  glands  .... 

Tricho-monas  ..... 

Troughs  for  dissection  .... 

Tube  cells 

Turpentine  injections    .... 
Turpin.    His  opinion  that  the  milk  globules  con- 
sist of  two  vesicles  enclosing  fine  globules 
and  buttery  oil  ...  197 

His  idea  that"  the  fungus,  penicillum  glaucum, 
was  developed  from  the  milk;  globules   .        216 

Urine.    Specific  gravity  of  245 

Analysis  of     .....        240 
Solid  organic  constituents  of,  viz :  mucous  cor- 
puscles and  epithelial  scales         .  .        246 
Spermatozoa  in   .           .           .           .  .  246 
Pathology  of  .           .           .           .           .246 
To  examine          .....  252 
Uterine  glands               ....       420 
Uterine  and  Fallopian  tubes        .           .       413. 419 
Spheroidal  epithelium  of     .           .           .413 

420 
35 

80 
223 

2 -J  4 
230 
271 


Vaginal  glands        .  .  .  .  . 

Valentin's  knife  .... 

Valentin.    On  quantity  of  blood  in  the  system 

On  the  supposed  stomach  of  spermatozoa 

On  the  spermatozoa  of  the  bear 

On  the  development  of  spermatozoa 

On  the  ciliated  epithelium  of  the  ventricles 

On  the  occurrence  of  pigmentary  ramifica- 
tions in  the  cervical  portion  of  pia  mater 

On  the  disposition  of  nucleated  or  gelatinous 
nerve  fibres       . 

On  the  termination  of  nerves  in  pulp  of  teeth 

On  the  structure  of  the  kidney 
Valentin  and  Schwann.    Their  researches  on  the 

development  of  muscular  fibre 
Valves  in  lymphatics   .... 
Veins,  injection  of  .  .  . 

Vibrious,  vaginal  .... 

Ditto  venereal  . 

Vicugna,  blood  of         ... 
Villi.     Of  the  intestines,  distribution  of 

Structure  and  epithelium  of 

Basement  membrane  and  nuclear  contents  of 

Oil-drops  in  and  blood-vessels  of    . 

Lacteals  and  peculiar  form  of   . 

Examination  and  injection  of 
Of  the  pia  mater  .  .  .  • 

Vision.    Structure  of  globe  of  the  eye      r    . 
Sclerotic.    Structure  of  . 

Tunica  albuginea  and  vessels  of 
Cornea.    Structure  and  lamina?  of 

Conjunctival  epithelium  and  cornea  proper 

Pf.atpj-inr  and  anterior  elastic  lamina     . 


PAOH 

Vision.    Epithelium  of  aqueous  humour      .        513 
Choroid.    Blood-vessels  of  .  .      514, 515 

Tunica  Euyschiana,  vense  vorticosa?  .        515 

Stellate  choroidal  epethelium    .  .  .  515 

Lamina  fusca  ....        516 

Hexagonal  choroidal  epithelium  .  .  516 

Tapetum  lucidum  ....  516 
Ciliary  and  second  ciliary  processes     .  .  517 

Zone  of  Zinn,  iris,  and  uvea  .  .        517 

Membrana  pupilaris  and  retina  .  .  518 

Tunica  Jacob],  granular  and  ganglionary  layer  519 
Vesicular,  fibrous  gray,  and  vascular  ditto  520, 521 
Optic  nerves,  vitreuus  body,  vitreous  humour  521 
Hyaloid  membrane  ....  521 
Crystalline  lens,  capsule,  body  and  fibres  of  522 
Structure  and  arrangement  of  ditto      .  .  522 

Vogel.  '  His  opinion  the  mucous  corpuscles  are 
formed  externally  to  the  blood-vessels    .        177 
Ditto  as  to  the  nature  of  pus  and  mucous 

globules 184 

On  the  stellate  bodies  observed  on  decompos- 
ing fat  vesicles        ....        259 
Volkman  and  Bidder.    On  the  origin  of  gelatin- 
ous filaments  from  the  ganglia  of  the  sym- 
pathetic .....  382 

Wagner.    On  the  blood  of  the  lamprey        .  91 

His  belief  in  the  existence  of  a  nucleus  in  the 

red  blood  disc  .  .  .  .93 

His  opinion  that  the  white  globules  are  red 

blood  corpuscles  in  process  of  formation        112 
On  the  milk  globules  .  .  .200 

On  the  structure  of  human  spermatozoa    .        224 
His  supposition  that  the  motions  of  spermato- 
zoa were  produced  by  a  ciliary  apparatus      226 
His  observation  of  spermatozoa" in  motion  at 

the  end  of  twenty-four  hours        .  .        227 

On  the  development  of  spermatozoa    .  .  229 

On   the   degeneration  of  the  testes  of  birds 
during  winter         ....        232 
i     On  spermatozoa  in  male  hybrids  .  .  232 

On  the  coloration  of  the  iris  of  birds  .  255 
On  the  development  of  nerves  .  .  338 

'  Waller,  Dr.  A.    On  the  tongue  of  the  frog   .        126 
Williams.  Dr.  T.    On  the  air  cells  of  the  lungs     396 
Willis.      His  translations  of  Wagner's   Physi- 
ology .....        388 
Wilson,  Mr.  Erasmus.    On  the  anatomy  of  epi- 
dermis  .  .  ...  280 
On  structure  of  the  striated  muscular  fibrilla    358 
Calculation  of  extent  of  sudoriferous  system      438 
Withoff.    On  the  number  of  hairs  existing  on 
different  surfaces  of  the  body       .  .        300 

Young.    His  disbelief  in  the  existence  of  a  nu- 
cleus in  the  red  blood  disc     .  .  .93 


Zinn.  zone  of 


517 


THE     END 


THE 


MICROSCOPIC  AIATOMY 

OF 

THE     HUMAN    BODY. 

IN 

HEALTH  AND  DISEASE. 

ILLUSTRATED   WITH   NUMEROUS  DRAWINGS   IN   COLOUR. 


BY 

ARTHUR    HILL    HASSALL,    M.  B. 

Author  of  a  "History  of  the  British  Fresh-water  Alga;;"  Fellow  of  the  Linn;ean  Society;  Member  of  the 

Royal  College  of  Surgeons  of  England ;  one  of  the  Council  of  the  London  Botanical  Society ; 

Corresponding  Member  of  the  Dublin  Natural  History  Society,  &e. 


ADDITIONS   TO   THE   TEXT   AND    PLATES, 

AND 

AN      INTRODUCTION, 

CONTAINING    INSTRUCTIONS   IN   MICROSCOPIC    MANIPULATION, 
BY 

HENRY  VANARSDALE,  M,  D. 

IN    TWO    VOLUMES. 

VOL.  II. 

NBW-YOEK: 
PRATT,   WOODFORD    &    CO. 

BOSTON:  T1CKNOR.  REED,  &  FIELDS;   PHILADELPHIA:  LIPPINCOTT.  GRAMBO  &  CO. 
CINCINNATI:  H.  W.  DERBY  &.  CO.;    HARTFORD:  E.  C.  KELLOGG. 

1851. 


ENTERED,    ACCORDING    TO    ACT    OF    CONGRESS,    IN    THE    YEAR    1851,    BY 

E.    C.   KELLOGG, 

IN    THE    CLERK'S    OFFICE    OF    THE    DISTRICT    COURT   OF   CONNECTICUT. 


FOUNDRY      OF  PRESS     OF 

SILAS    ANDRUS    AND    SON,  F.    C.    GUTIERREZ, 

HARTFORD.  NEW-YORK. 


INDEX  OF  THE  ILLUSTRATIONS. 


THE    WHOLE     OF     THE     FOLLOWING    ILLUSTRATIONS     ARE 
ORIGINAL     WITH     BUT     NINE     EXCEPTIONS: 


BLOOD. 

Corpuscles  of  man,  the  red  with  the  centres  clear,  670  diam. 

The  same,  the  red  with  the  centres  dark,  670  diam. 

The  same,  seen  in  water,  670  diam.     ..... 

The  same,  the  red  united  into  rolls,  670  diam. 
Tuberculated  condition  of  the  red  corpuscles,  670  diam. 
White  corpuscles  of  man,  in  water,  670  diam. 
Corpuscles  of  frog,  670  diam.        ...... 

The  same,  with  the  nucleus  of  the  red  visible,  670  diam. 
The  same,  in  water,  670  diam.  ..... 

The  same,  after  prolonged  action  of  water,  670  diam. 

Nuclei  of  red  corpuscles  of  frog,  670  diam. 

Elongation  of  red  corpuscles  of  ditto,  670  diam. 

Corpuscles  of  the  dromedary,  670  diam. 

The  same  of  the  siren,  670  diam. 

The  same  of  the  alpaco,  670  diam. 

The  same  of  the  elephant,  670  diam. 

The  same  of  the  goat,  670  diam. 

Peculiar  concentric  corpuscles  in  blood,  670  diam. 

Coagulated  fibrin,  670  diam 

The  same  with  granular  corpuscles,  670  diam. 

Corpuscles  of  earth-worm,  670  diam. 

Circulation  in  tongue  of  frog,  350  diam. 

The  same  in  web  of  the  foot  of  ditto,  350  diam. 

Corpuscles  in  vessels  of  the  same,  670  diam. 

White  corpuscles  in  vessels  of  the  same,  900  diam. 

Glands  of  tongue  of  frog,  130  diam. 

Under  surface  of  tongue  of  same,  500  diam. 

Red  corpuscles  of  embryo  of  fowl,  670  diam. 

The  same,  in  water,  570  diam. 

Red  corpuscles  of  adult  fowl,  670  diam. 

The  same  of  young  frog,  670  diam. 

The  same  of  the  adult  frog,  670  diam. 

The  same  united  into  chains,  670  diam. 


Flute 


I. 

tig.  1 

I. 

«     2 

I. 

"     3 

I. 

«     4 

I. 

"     5 

I. 

"     6 

II. 

"     1 

II. 

"     2 

II. 

"     3 

II. 

"     4 

II. 

"     5 

II. 

«     6 

III. 

"     1 

III. 

«     2 

III. 

"     3 

IV. 

"     1 

IV. 

"     2 

IV. 

"     3 

IV. 

"     4 

IV. 

"     5 

IV. 

"     6 

V. 

"     1 

V. 

"     2 

VI. 

"     1 

VI. 

"     2 

VII. 

"     1 

VII. 

"     2 

IX. 

"     1 

IX. 

"     2 

IX. 

«     3 

IX. 

"     4 

IX. 

"     5 

IX. 

"     6 

INDEX     OF     THE     ILLUSTRATIONS, 


DEVELOPMENT    OF   EMBRYO    OF    CHICK. 


The  cicatricula  prior  to  incubation 

The  same  at  the  end  of  first  day  of  incubation 

The  same  at  the  thirty-sixth  hour     . 

The  same  at  the  close  of  the  second  day 

The  same  at  the  end  of  the  third  day 

The  embryo  on  the  conclusion  of  the  fourth  day 

The  same  at  the  termination  of  the  fifth  day 

The  embryo  of  six  days  old  .... 

The  embryo  of  the  ninth  day  of  development.    . 

The  same  at  the  end  of  the  seventh  day,  detached 

Ditto  at  the  end  of  the  ninth  day,  also  detached 


Plate 


X. 

Fig.  1 

X. 

"     2 

X. 

"     3 

X. 

"     4 

X. 

"     5 

X. 

"     6 

X. 

"     7 

X. 

"     8 

X. 

"     9 

X. 

"  10 

X. 

*<  11 

MUCUS. 

Corpuscles  of,  in  their  ordinary  condition,  670  diam. 

The  same  collapsed,  670  diam.         ..... 

The  same,  showing  the  action  of  water,  670  diam. 

The  same  acted  on  by  dilute  acetic  acid,  670  diam. 

The  same  after  the  action  of  undilute  acetic  acid,  670  diam. 

The  same  in  process  of  development,  670  diam. 

Vaginal-  mucus,  670  diam.  .         .  •   . 

^Esophageal  mucus,  670  diam.  ..... 

Bronchitic  ditto,  670  diam.  .         .         .         . 

Vegetation  in  mucus,  670  diam.        ..... 

Mucus  of  stomach,  670  diam 

Vaginal  tricho-monas       ....... 


XI. 

'    1 

XI. 

'     2 

XI. 

'     3 

XI. 

<     4 

XI. 

'     5 

XI. 

'     6 

XII. 

'     1 

XII. 

'     2 

XII. 

'     3 

XII. 

'    4 

XII. 

'     5 

XII. 

•     G 

PUS. 


Corpuscles  of  laudable  pus,  670  diam. 
The  same  acted  on  by  acetic  acid,  670  diam. 
The  same  treated  with  water,  670  diam. 
Epithelial  scales  from  pustule,  670  diam. 
Corpuscles  from  scrofulous  abscess,  670  diam. 
Vibrios  in  venereal  pus,  670  diam. 


XIII. 

'    1 

XIII. 

'     2 

XIII. 

'     3 

XIII. 

'     4 

XIII. 

'     5 

XIII. 

•     6 

MILK. 


Globules  of  healthy  milk  of  woman,  670  diam. 
The  same  of  impoverished  human  milk,  670  diam. 
Colostrum,  670  diam.  ..... 

Ditto,  with  several  corpuscles,  670  diam. 

Globules-of  large  size,  670  diam. 

Ditto,  aggregated  into  masses,  670  diam. 

Pus  in  the  milk  of  woman,  670  diam. 

Blood  corpuscles  in  the  human  milk,  670  diam. 

Globules  after  treatment  by  ether,  670  diam. 

The  same  after  the  application  of  acetic  acid,  670  diam 


XIV. 

'    1 

XIV. 

'     2 

XIV. 

'     3 

XIV. 

'     4 

XIV. 

'     5 

XIV. 

•     G 

XV. 

■     1 

XV. 

'    2 

XV. 

'     3 

XV. 

'     4 

INDEX     OF     THE     ILLUSTRATIONS.  O 

Caseine  globules,  670  diam Plate     xv.  Fig.  5 

Milk  of  cow  adulterated  with  flour,  G70  diam "         xv.     "     6 


SEMEN, 

Spermatozoa  and  spermatophori  of  man,  900  diam. 
Spermatozoa  of  Certhia  familiaris 

FAT. 


The  fat  vesicles  of  a  child,  130  diam 

Ditto  of  an  adult,  130  diam. 

Ditto  or  the  pig,  with  apparent  nucleus,  130  diam. 

Ditto  of  the  same,  ruptured,  130  diam.  .... 

Ditto  of  marrow  of  the  femur  of  a  child,  130  diam.     . 

Ditto,  with  the  membranes  of  the  vesicles  ruptured,  130  diam. 

Crystals  on  human  fat  vesicles,  130  diam.  .... 

Fat  vesicles  in  melicerous  tumour,  130  diam. 

Ditto  contained  in  parent  cells,  120  diam.  .... 

Ditto  after  the  absorption  of  the  parent  cell-membrane,  120  diam. 


XVI. 
XVI. 


XVIII. 

"    1 

XVIII. 

«     2 

XIX. 

«    1 

XIX. 

«     2 

XIX. 

"     3 

XIX. 

"    4 

XIX. 

"     5 

XIX. 

"     6 

LXIX. 

"  10 

LXIX. 

«  11 

EPITHELIUM. 


Buccal  epithelial  cells,  670  diam. 

Cuneiform  ditto  from  duodenum,  670  diam. 

Ciliary  epithelium  from  trachea  of  frog,  670  diam. 

Human  ciliary  epithelium  from  lung,  670  diam. 

Ditto  from  trachea,  670  diam. 

Tesselated  epithelium  from  tongue  of  frog,  670  diam 

Ditto  from  tongue  of  triton,  670  diam. 

Ditto  from  serous  coat  of  liver,  670  diam. 

Ditto  from  choroid  plexus,  670  diam. 

Ditto  from  vena  cava  inferior,  670  diam. 

Ditto  from  arch  of  the  aorta,  670  diam. 

Ditto  from  surface  of  the  uterus,  670  diam.     . 

Ditto  from  the  internal  surface  of  the  pericardium,  670  diam 

Ditto  of  lateral  ventricles  of  brain,  670  diam. 

Ditto  of  mouth  of  menobranchus  lateralis,  670  diam. 


XX. 

"    1 

XX. 

"     2 

XXI. 

"    1 

XXI. 

-    2 

XXI. 

"     3 

XXI. 

"     4 

XXI. 

"     5 

XXII. 

"     1 

XXII. 

"     2 

XXII. 

"    3 

XXII. 

"     4 

XXII. 

"     5 

XXII. 

"     6 

XXVI. 

"  6e 

XXVI. 

"  6d 

EPIDERMIS 

Upper  surface  of  epidermis,  130  diam. 

Under  surface  of  ditto,  130  diam.        .... 

Epidermis  of  palm,  viewed  with  a  lens  only, 

Ditto,  magnified  100  diam 

Vertical  section  of  ditto,  100  diam. 

Ditto  of  one  of  the  ridges,  100  diam. 

Epidermis  from  back  of  hand,  viewed  with  a  lens 

A  portion  of  same  more  highly  magnified,  100  diam. 

Epidermis  from  back  of  hand  100  diam. 

Ditto,  viewed  on  its  under  surface,  100  diam. 

Portion  of  ditto,  with  insertion  of  hairs,  100  diam. 


XXIII. 

<    1 

XXIII. 

•     2 

XXIV. 

•    1 

xxiv. 

'     2 

XXIV. 

'     3 

XXIV. 

'     4 

XXIV. 

'     5 

XXIV. 

'     6 

XXVI.       ' 

<     1 

XXVI.       ' 

'    2 

xxvi.     "     3 

INDEX     OF     THE     ILLUSTRATIONS, 


Ditto  from  back  of  neck,  670  diam. 
Detached  cells  of  epidermis,  670  diam. 
Cells  of  vernix  caseosa,  130  diam. 
Cells  of  ditto,  670  diam'. 


NAILS. 


Longitudinal  section  of  nail,  130  diam 

Ditto,  showing  unusual  direction  of  stria?,  130  diam. 
Ditto,  with  different  distribution  of  striae,  130  diam. 
Transverse  section  of  nail,  130  diam.      ..... 

Cells  of  which  the  layers  are  formed,  130  diam.  and  670  diam. 
Union  of  nail  with  true  skin,  100  diam.  '  . 


.  Plate  xxvi.  Fig.  5 
"  xxvi.  "6a 
"  xxvi.  "6b 
"     xxvi.     "6c 


"         XXV. 

'    1 

"         XXV. 

<     2 

"         XXV. 

'     3 

"         XXV. 

'     4 

"         XXV.       ' 

'     5 

"       XXVI. 

'     4 

PIGMENT    CELLS. 


Cells  of  pigmentum  nigrum  (human),  760  diam. 
Ditto  of  the  same  of  the  eye  of  a  pig,  350  diam. 
Stellate  cells  of  lamina  fusca,  100  diam. 
Ditto  more  highly  magnified,  350  diam. 
Cells  of  skin  of  negro,  670  diam. 

Ditto  from  lung,  670  diam 

Cells  in  epidermis  of  negro,  350  diam. 

Ditto  in  areola  of  nipple,  350  diam.  .         . 

Ditto  of  bulb  or  hair,  670  diam. 


"     XXVTI. 

"    1 

"     XXVII. 

"     2 

"    xxvii. 

"     3 

"      XXVII. 

"4a 

"     XXVII. 

"4b 

"      XXVII. 

"4  c 

"    xxvii. 

"     5 

"     XXVII. 

"     6 

"    XXVIII. 

"     5 

HAIR, 


Bulb  of  hair,  130  diam 

Root  of  a  gray  hair,  130  diam.  .         . 

Cells  of  outer  sheath,  670  diam 

Portion  of  inner  sheath,  350  diam. 

Stem  of  gray  hair  of  scalp,  350  diam. 

Transverse  section  of  hair  of  beard,  130  diam. 

Another  section  of  the  same,  130  diam. 

Fibres  of  the  stem  of  the  hair,  670  diam. 

Apex  of  hair  of  perineum,  350  diam. 

Ditto  of  scalp,  terminating  in  fibres,  350  diam.    . 

Ditto  of  same  with  needle-like  extremity,  350  diam. 

Root  of  hair  of  scalp,  130  diam. 

Another  form  of  same,  130  diam.    .         .         . 

Hair  with  two  medullary  canals,  130  diam. 

Insertion  of  hairs  in  follicles,  100  diam. 

Disposition  of  hairs  on  back  of  hand. 

CARTILA  GE 

Transverse  section  of  cartilage  of  rib,  350  diam. 
Parent  cells  seen  in  section  of  ditto,  350  diam. 
Vertical  section  of  articular  cartilage,  130  diam. 
Ditto  of  inter-vertebral  cartilage,  80  diam. 
Cartilage  of  concha  of  ear,  350  diam.     . 


XXVIII. 

"    1 

XXVIII. 

"     2 

XXVIII. 

"     3 

XXVIII. 

"     4 

XXIX. 

"    1 

XXIX. 

"     2 

XXIX. 

"     3 

XXIX. 

"     4 

XXIX. 

"     5 

XXIX. 

"     6 

XXIX. 

"     7 

XXTX. 

(     8 

XXIX. 

"     9 

XXIX. 

'  10 

XXVI. 

'     3 

XXIV.       ' 

«     5 

XXX. 

'    1 

XXX. 

«     2 

XXX. 

'     3 

XXX. 

'     4 

XXXI. 

'     1 

INDEX     OF     THE     ILLUSTRATIONS 


Cells  of  inter-vertebral  cartilage,  350  diam. 
Section  of  cartilage  and  bone  of  rib,  130  diam. 
Ditto  of  one  of  the  rings  of  the  trachea,  350  diam. 
Ditto  of  thyroid  cartilage  with  fibres,  130  diam. 
Cartilage  of  ossification,  100  diam. 
Section  of  primary  cancelli,  350  diam. 
Ditto  of  same,  more  advanced,  350  diam. 
Cartilage  of  ossification,  350  diam. 
Section  of  cartilaginous  epiphysis,  30  diam. 
Ditto  of  same,  with  bone,  30  diam. 
Ditto  of  same,  more  highly  magnified,  330  diam. 
Section  of  cartilage  and  bone  of  rib,  130  diam. 


.    Plate  xxxi. 

Fig 

2 

"        XXXI. 

c( 

3 

"       XXXI. 

" 

4 

"       XXXI. 

" 

5 

"     XXXIV. 

" 

1 

"    XXXIV. 

" 

2 

"     XXXIV. 

" 

3 

"    XXXIV. 

" 

4 

"      XXXV. 

" 

1 

"       XXXV. 

" 

2 

"       XXXV. 

" 

.') 

"       XXXV. 

" 

6 

BONE. 

Transverse  section  of  ulna,  60  diam. 

Cross-section  of  Haversian  canals,  220  diam. 

Ditto  of  same  more  highly  magnified,  670  diam. 

Longitudinal  section  of  long  bone,  40  diam. 

Parietal  bone  of  foetus,  30  diam.         .         . 

Portion  of  same  more  highly  magnified,  60  diam. 

Spicula  of  bone  of  foetal  humerus,  350  diam. 

Lamina  of  a  long  bone,  500  diam. 

Cancelli  of  long  bone  of  foetus,  350  diam. 

Section  of  femur  of  pigeon  fed  on  madder,  220  diam. 

Section  of  epiphysis  and  shaft  of  foetal  femur,  100  diam. 

Transverse  section  of  primary  cancelli,  350  diam. 

Section  of  cancelli  more  advanced,  350  diam. 

Ditto  of  epiphysis  and  shaft  of  fetal  femur,  350  diam. 

Ditto  of  cartilaginous  epiphysis  of  humerus,  30  diam. 

Ditto  of  same  with  bone,  30  diam. 

The  same  more  highly  magnified,  330  diam. 

Blood-vessels  and  medullary  cells        .... 

Section  of  shaft  of  fetal  long  bone,  20  diam. 

Ditto  of  bone  and  cartilage  of  rib,  130  diam. 


XXXII. 

'    1 

XXXII.       ' 

«     2 

XXXII.       ' 

'     3 

XXXII. 

'     4 

XXXIII. 

'    1 

XXXIII. 

'     2 

XXXIII. 

'     3 

XXXIII. 

'     4 

XXXIII. 

<     5 

XXXIII. 

«     6 

xxxiv. 

'     1 

XXXIV. 

'    2 

XXXIV. 

'    3 

XXXIV. 

'     4 

XXXV. 

(     1 

XXXV. 

"    2 

XXXV. 

"     3 

XXXV. 

"     4 

XXXV. 

"     5 

XXXV. 

'     6 

TEETH. 

Vertical  section  of  incisor  tooth,  seen  with  lens 
Tubes  of  dentine  near  their  termination,  670  diam. 
A  not  unfrequent  condition  of  same,  670  diam. 
Tubes  of  dentine  near  their  commencement,  670  diam. 
Oblique  section  of  tubes  of  dentine,  670  diam. 
Transverse  section  of  ditto,  670  diam.    . 
Transition  of  tubes  into  bone  cells,  670  diam.   . 
Dilatation  of  ditto  into  bone  cells,  670  diam. 
Section  of  cementum,  670  diam.         .... 
Ditto  of  same  traversed  by  tubes,  670  diam. 
Ditto  of  same  showing  angular  cells,  670  diam. 
Fungus  on  section  of  dentine,  670  diam. 
Oil-like  globules  on  section  of  same,  350  diam. 


XXXVI. 

'    1 

XXXVI. 

«     2 

XXXVI. 

'     3 

XXXVI. 

<     4 

XXXVI. 

'     5 

XXXVI. 

'     6 

XXXVI. 

«     7 

XXXVI. 

'     8 

XXXVII. 

'     1 

XXXVII. 

'    2 

XXXVII. 

'    3 

XXXVII. 

'     4 

XXXVII. 

'     5 

8 


INDEX     OF     THE     ILLUSTRATIONS, 


Section  of  secondary  dentine,  350  diam. 
Ditto  of  bicuspid  tooth,  seen  with  lens  only 
Vertical  section  of  enamel,  220  diam.    . 
Enamel  cells  seen  lengthways,  G70  diam. 
Cross-section  of  cells  of  enamel,  670  diam. 


Plate  xxxvu.  Fig.  6 
"  xxxvu.  "  7 
"  xxxix.  "  3 
"  xxxix.  "  4 
"    xxxix.     "     5 


FIBROUS    TISSUE, 

Longitudinal  section  of  tendon,  670  diam. 
Transverse  section  of  same,  670  diam. 

White  fibrous  tissue,  670  diam. 

Mixed  ditto,  670  diam 

Yellow  fibrous  tissue,  670  diam.        ..... 

Different  form  of  ditto,  670 

Development  of  blood-vessels,  350  diam. 
Areolar  form  of  mixed  fibrous  tissue,  330  diam. 
Blood-vessels  of  pia  mater,  350  diam.       .... 
Development  of  white  fibrous  tissue,  670  diam. 

Portion  of  dartos,  670  diam.    - 

Section  of  corpora  cavernosa,  slightly  magnified    . 


XXXIX.       ' 

<       1 

XXXIX.      ' 

<    2 

xxxix.     "     6 

XXXIX. 

'     7 

XL. 

'     1 

XL. 

'     2 

XL. 

'     3 

XL. 

«     4 

XL. 

'     5 

XLIII. 

"    2 

XLIII. 

'     3 

XLIII. 

"     4 

MUSCLE. 

Portion  of  striped  muscle,  60  diam. 
Fragment  of  unstriped  ditto,  670  diam. 
Muscular  fibrillse  of  the  heart,  670  diam. 
Fragment  of  striped  muscle  of  frog,  350  diam. 
Fibres  and  fibrillae  of  voluntary  muscle,  350  diam.     . 
Fibres  acted  on  by  acetic  acid,  350  diam. 
Ditto  in  different  degrees  of  contraction,  350  diam. 
Union  of  muscle  with  tendon,  130  diam. 
Transverse  section  of  muscular,  fibres,  350  diam. 
Fibres  of  voluntary  muscle  of  fcetus,  660  diam. 
Zigzag  disposition  of  fibres,  350  diam. 
Striped  muscular  fibre  and  fibrillae,  670  diam. 


XLI. 

'       1 

XLI. 

«    2 

XLI. 

'     3 

XLI. 

'     4 

XLII. 

•     1 

XLII. 

<    2 

XLII. 

<    3 

XLII. 

<     4 

XLII. 

•     5 

XLIII. 

'     1 

XLIII. 

"    5 

XLIII. 

"     6 

NERVES, 

Tubes  of  motor  nerve,  670  diam 

The  same  after  the  action  of  spirit,  670  diam. 
The  same  after  the  action  of  acetic  acid,  670  diam. 
Portion  of  Casserian  ganglion,  350  diam. 
Nerve  tubes  of  cerebellum,  670  diam. 
Ditto  of  cerebrum,  with  clear  cells,  670  diam. 
Varicose  condition  of  ditto,  670  diam. 
Filaments  of  great  sympathetic,  670  diam.    . 
Cells  of  gray  matter  of  cerebellum,  670  diam. 
Ditto  of  same,  inner  stratum,  670  diam. 
Caudate  ganglionary  cells,  350  diam. 

(Spinal  cord,  Medulla  oblongata,  Cerebellum.) 
Ditto  from  locus  niger  of  crus  cerebelli,  350  diam. 


XLIV. 

'       1 

XLIV.      "      2 

XLIV. 

•     3 

XLIV. 

'     4 

XLIV. 

'     5 

XLIV. 

'     6 

XLIV. 

<     7 

XLV. 

'     1 

XLV. 

«    2 

XLV. 

"    3 

XLV. 

«     4 

INDEX     OF     THE     ILLUSTRATION 


Ditto  from  hippocampus  major,  350  diam. 

Ditto  from  locus  niger  of  crus  cerebri,  350  diam.   . 

Pacinian  bodies,  natural  size    ..... 

Ditto,  magnified  60  diam.    ..... 

A  single  Pacinian  body,  100  diam. 

An  anomalous  Pacinian  body        .... 

Two  other  anomalous  Pacinian  bodies 

Cells  from  corpus  dentatum  of  cerebellum,  350  diam. 


Dlate  xlv. 

Fig 

6 

"           XLV. 

" 

7 

"         XLVI. 

" 

1 

"         XLVI. 

a 

2 

"         XLVI. 

" 

3 

"          XLVI. 

" 

4 

"         XLVI. 

" 

5 

"         XLVI. 

« 

6 

LUBJG, 

Pleural  surface  of  lung,  30  diam.      ...... 

Ditto,  with  vessels  of  first  order,  30  diam 

Ditto,  magnified  100  diam 

Section  of  lung  injected  with  tallow,  100  diam.     . 

Casts  of  air-cells,  350  diam 

Section  of  lung  injected  with  size,  100  diam. 
Pleural  surface  of  lung,  with  vessels  of  second  order,  100  diam. 
Section  of  lung,  with  air-cells  uninjected,  100  diam. 
Capillaries  of  lung,  100  diam. 


XLVII. 

'       1 

XL  VII. 

'    2 

XLVII.  • 

'     3 

XLVIII. 

'     1 

XL  VIII. 

'    2 

XLVIII. 

'     3 

XLIX. 

'     1 

XLIX. 

«     2 

XLIX. 

'    3 

GLANDS, 

Follicles  of  stomach,  with  epithelium,  100  diam. 
Ditto  of  large  intestine,  in  similar  condition,  100  diam 
Ditto  of  same,  without  epithelium,  60  diam. 
Termination  of  follicles  of  large  intestine,  60  diam. 
Follicles  of  Leiburkuhn  in  duodenum,  60  diam.     . 
Vessels  of  ditto  of  appendix  vermiformis,  100  diam. 
Ditto  of  same  of  stomach  of  cat,  100  diam. 
Stomach  tubes,  cross-section  of,  100  diam. 
Longitudinal  view  of  stomach  tubes,  220  diam.     . 
Ditto  of  the  same,  100  diam.  .... 

Villi  of  small  intestine,  with  epithelium,  100  diam. 
Ditto,  without  epithelium,  showing  lacteals,  100  diam. 
Vessels  of  villi  in  duodenum,  60  diam. 
Ditto  of  same  in  jejunum,  60  diam. 
Ditto  of  same  of  foal,  60  diam.    .... 
Solitary  glands  of  small  intestine,  natural  size 
Ditto  of  large  intestine,  slightly  magnified    . 
Aggregated  or  Feyefs  glands,  20  diam. 

Side  view  of  same,  20  diam 

Sebaceous  glands  in  connexion  with  hair,  33  diam. 
Ditto  from  caruncula  lachrymalis 
An  entire  Meibomian  gland,  27  diam.     . 
Illustrations  of  Mucous  glands,  45  diam. 
Farotid  gland  of  embryo  of  sheep,  8  diam.     . 
Ditto  of  human  subject,  further  developed,  40  diam. 
Mammary  gland,  portion  of,  slightly  magnified 
Ditto  of  same,  with  milk  globules,  90  diam. 


L. 

it 

1 

L. 

tc 

2 

L. 

" 

6 

L. 

" 

7 

LII. 

« 

5 

LI. 

tc 

1 

LI. 

ft 

2 

L. 

" 

3 

L. 

(C 

4 

L. 

« 

5 

LII. 

" 

1 

LII. 

" 

2 

LI. 

" 

3 

LI. 

u 

4 

LI. 

lxii. 

" 

5 
6 

LI. 

« 

6 

LII. 

" 

3 

LII. 

" 

4 

LIII. 

" 

3 

LIII. 

" 

1 

LIII. 

cc 

2 

LIII. 

" 

4 

LIT. 

" 

1 

LIV. 

" 

o 

LIV. 

" 

5 

LIV. 

" 

3 

10 


INDEX     OF     THE     ILLUSTRATIONS, 


Ditto  of  same  more  highly  magnified,  198  diam. 
Liver,  section  of,  showing  the  lobules,  35  diam.    . 
Surface  of  ditto,  showing  the  intra-lobular  veins,  15  diam. 
Section  of  liver  showing  the  hepatic  venous  plexus,  20  diam 
Vessels  of  portal  system,  20  diam.  .... 

Section  of  liver,  showing  inter-lobular  vessels,  24  diam. 
Surface  of  liver,  showing  portal  capillary  system,  20  diam. 
Ditto,  showing  both  hepatic  and  portal  venous  systems,  20  diam 
Ditto,  with  both  systems  completely  injected,  20  diam 
Ditto,  with  portal  vein  and  hepatic  artery,  18  diam. 

A  terminal  biliary  duct,  378  diam 

Secreting  cells  of  liver  in  healthy  state,  378  diam. 

Ditto,  gorged  with  bile,  378  diam. 

Ditto,  containing  oil  globules,  378  diam. 

Prostate  gland,  calculi  of,  45  diam. 

New  tubular  gland  in  axilla,  54  diam.  .         .    • 

Tubulus  of  ditto,  198  diam 

Ceruminous  glands,  portions  of,  45  diam.    . 
Sudoriferous  gland,  tubulus  of,  198  diam. 
Kidney,  tubes  of,  with  epithelium,  99  diam. 
Cross-section  of  elastic  frame-work,  99  diam.   . 
Ditto  of  frame-work  and  tubes,  99  diam.     . 
Section  of  vessels  in  tubular  part  of  kidney,  33  diam. 
The  same  vessels  seen  lengthways,  33  diam. 

Tubes  with  epithelium,  378  diam , 

Corpora  Malpighiana  of  kidney,  injected,  40  diam. 
Uriniferous  tubes  of  a  bird,  40  diam.        .... 
Corpora  Malpighiana  of  the  horse,  40  diam. 
Inter- tubular  vessels  of  surface  of  kidney,  90  diam. 
Transverse  section  of  injected  kidney,  67  diam. 
Uninjected  corpora  Malpighiana 

With  capsule,  100  diam 

Without  ditto,  100  diam.  . 

Malpighian  body,  more  highly  magnified,  125  diam. 
Afferent  and  efferent  vessels  of  Malpighian  tuft,  45  diam. 
Epithelial  cells  of  the  tubes,  378  diam. 

Testis,  tubes  of,  27  diam 

Tubes  of  ditto,  more  highly  magnified,  99  diam. 
Vessels  of  thyroid  gland,  injected,  18  diam.     . 
Vesicles  of  ditto,  viewed  with  a  lens  only     . 
Ditto  of  same,  magnified  40  diam.  .... 

Ditto  of  same,  showing  the  structure  of  their  walls,  67  diam 
Lobes  and  vesicles  of  same  in  their  ordinary  condition,  27  di 
Nuclei  of  vesicles  of  thyroid,  378  diam.  .... 
Follicles  of  thymus,  with  vessels,  33  diam. 

Capsule  of  ditto,  54  diam 

Nuclei  and  simple  cells  of  same,  378  diam. 
Compound  or  parent  cells  of  ditto,  378  diam. 
Spleen,  nuclei  and  vessels  of,  378  diam.  . 


Plate    liv. 

Fig.  6 

"              LIV. 

"     4 

"                LV. 

"     1 

"                LV. 

"     2 

"               LV. 

"    3 

"               LV. 

"     4 

"               LV. 

"     5 

"              LVI. 

"     3 

"              LVI. 

«     4 

"              LVI. 

"    2 

"            LVII. 

"     1 

"            LVII. 

"2a 

"            LVII. 

"2b 

"            LVII. 

"  2c 

"             LVII. 

"     3 

"            LVII. 

"  4a 

"            LVII. 

"  4b 

"            LVII. 

"     5 

"            LVII. 

"  4c 

"           LVIII. 

"     1 

"           LVIII. 

"     2 

"           LVIII. 

"     3 

"           LVIII. 

"     4 

"           LVIII. 

"     5 

"           LVIII. 

"     6 

"           LXIX. 

"     1 

"              LIX. 

"     2 

"              LIX. 

"     3 

"              LIX. 

"     4 

"              LIX. 

"     5 

"                LX. 

"     2 

"                 " 

"       A 

"                 " 

"       B 

"               LX. 

"3a 

"               LX. 

"  3b 

"               LX. 

"  3o 

"               LX. 

"     1 

"               LX. 

"     4 

"             LXI. 

"     1 

"              LXI. 

"     2 

"              LXI. 

"    3 

"              LXI. 

"     4 

"              LXI. 

"     5 

"              LXI. 

"     6 

"             LXI. 

<-•     7 

"              LXI. 

"     8 

"              LXI. 

"     9 

"              LXI. 

"  10 

"            LXII. 

"     1 

INDEX     OP     THE     ILLUSTRATIONS, 


11 


Supra-renal  capsule,  plexus  on  surface  of,  54  diam.    . 

Tubes  of  ditto,  90  diam 

Nuclei,  parent  cells,  and  molecules  of  ditto,  378  diam. 
Vessels  of  supra-renal  capsule,  90  diam. 
Pineal  gland,  compound  bodies  of,  130  diam. 
Pituitary  gland,  cells  and  fibrous  tissue  of,  350  diam. 


Plate     lxii.  Fig.  2 


LXII. 

"3a 

LXII. 

"  36 

LXII. 

"     5 

LXIX. 

"     7 

LXIX. 

"     8 

ANATOMY    OF    THE    SENSE    OF    TOUCH. 

Epidermis  of  palm  of  hand,  40  diam.  .....  " 

Ditto  of  back  of  hand,  40  diam.     . " 

Papillae  of  palm  of  hand,  54  diam " 

Ditto  of  back  of  hand,  54  diam.    ......." 

Epidermis  of  palm,  under  surface  of,  54  diam.    ....  " 

Ditto  of  back  of  hand,  under  surface  of,  54  diam " 

Vessels  of  papilla?  of  palm  of  hand,  54  diam.      ....  " 

Ditto  of  same  of  back  of  hand,  54  diam.        ....." 


lxiii. 

'       1 

LXIII. 

'     2 

LXIII. 

'     3 

LXIII. 

<     4 

LXIII. 

'     5 

LXIII. 

'     6 

LXIII. 

«     7 

LXIII. 

<     8 

ANATOMY  OF  THE  SENSE  OF  TASTE, 

Filiform  papilla?,  with  long  epithelial  appendages,  41  diam. 

Ditto,  with  shorter  epithelial  processes,  27  diam. 

Ditto,  without  epithelium,  near  apex  of  tongue,  27  diam.    . 

Ditto,  without  epithelium,  near  centre  of  same,  31  diam. 

Filiform  and  fungiform  papillas,  without  epithelium,  27  diam. 

Peculiar  form  of  compound  papillae,  27  diam. 

Filiform  papilla?  in  different  states,  27  diam. 

Ditto,  with  epithelium  partially  removed,  27  diam. 

Follicles  of  tongue,  with  epithelium,  27  diam. 

Ditto,  without  epithelium,  27  diam.         .... 

Ditto,  viewed  as  an  opaque  object,  27  diam. 

Filiform  papilla?  from  point  of  tongue,  27  diam.' 

Follicles  and  papilla?  from  side  of  ditto,  20  diam. 

Simple  papillae,  with  epithelium,  45  diam. 

Filiform  papillae,  with  ditto,  18  diam.  .... 

The  same,  viewed  with  a  lens  only         .... 

Side  view  of  certain  compound  papilla?,  20  diam. 

Simple  papilla  from  under  surface  of  tongue,  54  diam.    . 

Compound  and  simple  ditto  from  side  of  tongue,  23  diam. 

A  calyciform  papilla,  uninjected,  16  diam. 

Ditto,  with  the  vessels  injected,  16  diam.    .... 

Filiform  papillae  near  centre  of  tongue,  injected,  27  diam. 

Ditto  near  tip  of  tongue,  injected,  27  diam.         .         . 

Simple  papillae,  injected,  27  diam.  .... 

Fungiform  ditto,  injected,  27  diam 


" 

LXIV. 

"       1 

if 

LXIV. 

"     2 

" 

LXIV. 

"     3 

" 

LXIV. 

«     4 

it 

LXIV. 

"     5 

it 

LXIV. 

"     6 

" 

LXIV. 

«     7 

ft 

LXIV. 

"     8 

" 

LXV. 

"     1 

" 

LXV. 

"     2 

" 

LXV. 

"     3 

ti 

LXV. 

"     4 

it 

LXV. 

«     5 

" 

LXV. 

"     6 

it 

LXV. 

"     7 

•     \  " 

LXV. 

"     8 

(f 

LXV. 

"     9 

. 

LXV. 

"  10 

" 

LXV. 

"  11 

A 

LXVI. 

"     1 

" 

LXVI. 

"     2 

" 

LXVI. 

"     3 

" 

LXVI. 

"     4 

" 

LXVI. 

•     5 

a 

LXVI. 

'     6 

ANATOMY     OF    THE     GLOBE     OF    THE     EYE. 


Vertical  section  of  cornea,  54  diam. 
A  portion  of  retina,  injected,  90  diam. 
Section  of  sclerotic  and  cornea,  54  diam. 


LXVII. 
LXV1I. 
LXVII. 


12 


INDEX     OF     THE     ILLUSTRATIONS. 


Vessels  of  choroid,  ciliary  processes,  and  iris,  14  diam 
Nuclei  of  granular  layer  of  retina,  378  diam. 

Cells  of  the  same,  378  diam 

Ditto  of  vesicular  layer  of  retina,  378  diam. 

Caudate  cells  of  retina,  378  diam.      .... 

Cells  of  the  membrana  Jacobi,  378  diam. 

Fibres  of  the  crystalline  lens;  a,  198  diam.  ;  b,  378  diam. 

A  condition  of  the  posterior  elastic  lamina,  78  diam. 

Peculiar  markings  on  same,  78  diam. 

Crystalline  lens  of  sheep,  slightly  magnified 

Fibres  of  lens  near  its  centre,  198  diam.    . 

Stellate  pigment  in  eye  of  sheep,  slightly  magnified 

Vena?  vorticosas  of  eye  of  sheep,  injected 

Conjunctival  epithelium,  oblique  view  of,  378  diam. 

Ditto,  front  view  of,  378  diam. 

Ciliary  muscle,  fibres  of,  198  diam. 

Gelatinous  nerve  fibres  of  retina,  378  diam. 

Cellated  structure  of  vitreous  body,  70  diam. 

Fibres  on  posterior  elastic  lamina,  70  diam. 

Portion  of  the  iris,  70  diam. 

Epithelium  of  crystalline  lens,  198  diam.  . 

Ditto  of  the  aqueous  humour,  198  diam. 

Hexagonal  pigment  of  the  choroid,  378  diam. 

Stellate  pigment  of  same,  378  diam.     . 

Irregular  pigment  of  uvea,  378  diam. 


Plate  lxvii.  F 

ig.  4 

"            LXVII. 

'     5 

"            LXVII. 

'     6 

"            LXVII. 

'     7 

"            LXVII. 

'     8 

"            LXVII. 

'     9 

"            LXVII. 

'  10 

"            LXVII. 

'  11 

"             LXVII. 

'  12 

"             LXVII. 

'  13 

"             LXVII. 

'  14 

"           LXVIII. 

'     1 

"            LXVIII. 

«    2 

"            LXVIII. 

'     3 

"            LXVIII. 

<     4 

"            LXVIII. 

'     5 

"            LXVIII. 

<     6 

"            LXVIII. 

'     7 

"           LXVIII. 

«    8 

"           LXVIII. 

'     9 

"            LXVIII. 

«  10 

"           LXVIII. 

'  11 

"           LXVIII. 

'  12 

"            LXVIII. 

'  13 

"           LXVIII. 

'  14 

AIAT0MY 


OF    THE 

!0  diam. 


NOSE. 


Mucous  membrane  of  true  nasal  region, 

Ditto  of  pituitary  region,  injected,  80  diam. 

Capillaries  of  olfactory  region  of  human  foetus,  100  diam. 


LXIX. 

"       1 

LXIX. 

"     2 

LXIX. 

"  12 

ANATOMY    OF    THE    EAR 

Denticulate  laminse  of  the  osseous  zone,  100  diam.     . 
Tympanic  surface  of  lamina  spiralis,  300  diam. 
Inner  view  of  cochlearis  muscle  of  sheep  ..... 
Plexiform  arrangement  of  cochlear  nerves  in  ditto,  30  diam. 


VILLI. 


Villi  of  foetal  placenta,  injected,  54  diam. 
Ditto  of  choroid  plexus,  45  diam. 


LXIX. 

'     3 

LXIX. 

<     4 

LXIX. 

'     5 

LXIX. 

'     6 

LXII. 

•     4 

LXII. 

'     9 

Plates  VIII.,  XVIL,  and  XXXVIII.,  omitted  in  the  original  edition,  are  likewise 
nere  omitted.  The  same  numbers  for  the  other  plates  are  observed,  that  the  figures 
in  both  editions  may  correspond. 

The  Plates  added  to  the  American  Edition  commence  at  Plate  LXX. 


PLATES    ADDED 


THE     AMERICAN     EDITION 


Corpuscles  of  lymph,  800  diam. 

Corpuscles  of  chyle,  800  diam. 

Fat  vesicles,  injected,  45  diam.     .... 

Transverse  sections  of  hair,  450  diam. 

Cartilage  from  finger-joint,  80  diam.     . 

Vessels  of  synovial  membrane,  45  diam.  . 

Injected  matrix  of  finger-nail,  10  diam. 

Vessels  of  tendon,  60  diam.     ..... 

Ditto  nearer  muscular  union,  30  diam. 
Lymphatic  gland  and  vessels,  8  diam.       ... 

Capillaries  and  air-cells  of  fcetal  lung,  60  diam.     . 
Ditto  of  same  of  child,  60  diam.       .... 

Ditto  of  same  of  adult,  60  diam. 

Braiichia  of  an  eel,  60  diam.   ..... 

Mucous  membrane  of  fcetal  stomach,  60  diam. 

Ditto,  showing  cells  and  cap.  ridges  of  adult,  60  diam. 

Ditto  with  cells  deeper  and  ridges  more  elevated,  60  diam 

Ditto  showing  gastric  villi,  60  diam. 

Villi  of  duodenum,  60  diam.         .... 

Ditto  of  jejunum,  60  diam.      .... 

Ditto  of  ileum,  60  diam 

Muscular  fibre  of  small  intestine,  60  diam. 

Appendix  vermiformis,  60  diam. 

Mucous  follicles  of  colon,  60  diam. 

Malpighian  bodies  with  uriniferous  tubes,  of  adult,  100  diam. 

Ditto  enlarged  as  in  Blight's  disease,  100  diam. 

Enlarged  veins  of  kidney,  first  stage  of  Bright's  disease, 

Ditto  of  same,  another  view,  100  diam. 

Stellated  veins  in  third  stage  of  same,  100  diam. 

Granulation  on  the  surface  of  kidney,  100  diam. 

A  tube  much  dilated,  100  diam.       .... 

Sudoriparous  glands  and  their  ducts,  70  diam. 

Ditto,  more  highly  magnified,  220  diam. 


100  diam. 


?la 

>e    lxx. 

Fig.  1 

" 

LXX. 

"    2 

" 

LXX. 

"    3 

SS 

LXX. 

"     4 

tt 

LXX. 

"    5 

tt 

LXX. 

"     6 

« 

LXXI. 

" 

SS 

LXXII. 

"     1 

St 

LXXII. 

"    2 

" 

LXXIII. 

"     1 

tt 

LXXIII. 

"    2 

te 

LXXIII. 

"     3 

SS 

LXXIII. 

«     4 

ts 

LXXIII. 

"    5 

St 

LXXIV. 

"     1 

" 

LXXIV. 

"    2 

tt 

LXXIV. 

"    3 

" 

LXXIV. 

"    4 

" 

LXXIV. 

"     5 

" 

LXXIV. 

"     6 

tt 

LXXV. 

"     1 

tt 

LXXV. 

"    2 

" 

LXXV. 

"    3 

" 

LXXV. 

"    4 

" 

LXXV. 

"     5 

" 

LXXV. 

"     6 

tt 

LXXVI. 

"     1 

« 

LXXVI. 

"    2 

ft 

LXXVI. 

"     3 

" 

LXXVI. 

"    4 

tt 

LXXVI. 

"    5 

tt 

LXX  VII. 

"     1 

« 

LXXVII. 

«    2 

14  INDEX     OF     THE     ILLUSTRATIONS. 

Mucous  membrane  of  gall-bladder,  50  diam Plate  lxxvii.  Fig.  3 

Transverse  section  of  muscles  of  the  tongue,  45  diam.     ..."  lxxvii.  "  4 

Terminal  vessels  in  cornea,  45  diam.            .....             "  lxxviii.  "  1 

Cornea  of  viper,  showing  its  vessels,  45  diam.                                                "  lxxviii.  "  2 

Choroid  coat  of  foetal  eye,  45  diam.     .......             "  lxxviii.  "  3 

Ciliary  processes  of  eye  of  adult,  45  diam.       ....."  lxxviii.  "  4 

Mucous  lining  of  unimpregnated  uterus,  35  diam.         ...             "  lxxviii.  "  5 

Ditto  of  impregnated  uterus,  35  diam "  lxxviii.  "  6 

Tuft  of  placenta,  60  diam. "  lxxix.  "  1 

Papillae  of  gum,  45  diam "  lxxix.  "  2 

Ditto  of  lip,  45  diam "  lxxix.  "  3 

Blood-vessels  in  mucous  membrane  of  trachea,  45  diam.          .         .         "  lxxix.  "  4 

Ditto  of  buccal  membrane,  60  diam. "  lxxix.  "  5 

Ditto  of  mucous  membrane  of  bladder,  60  diam "  lxxix.  "  6 


EXPLANATION  OF  THE  PLATES 

PLATE    I. 

The  figures  in  this  plate  are  magnified  670  diameters. 

THE    BLOOD    OP    MAN. 

Fig.  1.  The  human  red  blood  corpuscle,  showing  its  natural  form 
and  appearance  when  brought  fully  into  focus,  in  which 
case  the  centre  always  appears  light.  Scattered  over  the 
field  will  be  seen  one  or  two  white  corpuscles. 

2.  The  same,  with  the  centre  dark,  in  consequence  of  the  object 

not  being  brought  fully  into  focus. 

3.  The  same  in  water,  in  which  the  red  globules  lose  their  flat- 

tened and  discoidal  form,  becoming  circular,  and  presenting 
a  smaller  surface  to  view;  the  white  corpuscles  at  the  same 
time,  and  under  the  influence  of  the  same  agent,  are  seen 
to  have  increased  considerably  in  size. 

4.  The   same,   united  into  rolls,   as   of  miniature   money  in 

appearance. 

5.  The  same,  showing  the  peculiar  granulated  and  vesiculated 

appearance  which  they  so  frequently  present  under  such 
different  circumstances. 

6.  The  white  corpuscles  of  the  blood,  in  water,  in  which  they 

enlarge  considerably  in  dimensions,  often  appear  nucleated, 
and  after  long  immersion,  burst. 


Plate  I. 


H.MlliMiel 


E.CKtllodg.lith. 


18  EXPLANATION     OF     THE    PLATE 


PLATE    II, 


The  figures  in  this  plate  are  magnified  670  diameters. 

THE   BLOOD    OF    THE    FROG. 

Fig.  1.  The  blood  corpuscle  of  the  frog,  both  red  and  white,  with 
the  nucleus  of  the  former  seen  indistinctly. 

2.  The  same,  with  the  nucleus  distinctly  visible,  the  difference 

arising  from  the  greater  length  of  time  during  which  the 
latter  has  been  removed  from  the  system. 

3.  The  same,  in  water,  showing  the  change  of  form  which  the 

red  blood  corpuscle,  as  well  as  its  contained  nucleus,  under- 
goes in  that  fluid,  and  also  the  enlargement  of  the  white 
corpuscles. 

4.  The  same,  showing  the  effect  of  the  prolonged  action  of  water 

on  the  red  corpuscles;  the  nuclei  are  now  not  merely 
circular,  but  most  of  them  have  become  eccentric,  and 
certain  of  them  have  escaped  altogether  from  the  mem- 
branous capsular  portion  of  the  corpuscles,  which  and  the 
nuclei  are  seen  lying  side  by  side  as  distinct  structures. 

5.  The  nuclei,  separated   from  the   capsule  by  the  action  of 

acetic  acid. 

6.  Shows  the  extraordinary  deformity  and  elongation  of  which 

the  red  blood  corpuscles  are  susceptible  when  subject  to 
any  extending  force,  or  even  to  lateral  pressure.  In  the 
figure,  the  extension  has  been  exerted  on  the  corpuscles  by 
means  of  the  filaments  which  fibrin  in  coagulating  runs  into, 
and  a  portion  of  one  of  which  may  be  seen  uniting  the 
corpuscles. 

3 


PLccte  II 


Miller  del 


E.C.KelLoPS.lith 


20  EXPLANATION      OF     THE     PLATES, 


PLATE     III. 

The  figures  in  this  plate  are  magnified  670  diameters. 

For  the  blood  from  which  the  figures  contained  in  this  plate  were 
made,  as  well  as  some  of  those  of  the  following  plate,  I  am  indebted 
to  the  kindness  of  Mr.  Ogilby,  the  Secretary  of  the  Zoological  Society, 
who,  on  my  application  to  him,  promptly  and  courteously  forwarded 
to  me  the  permission  requisite  to  enable  me  to  obtain  it. 

Fig.  1.  The  red  and  white  blood  corpuscles  of  the  dromedary;  in 
water,  the  former  became  perfectly  spherical. 

2.  The  same,  of  the  Siren. 

3.  The  same,  of  the  Alpaco. 


Plate  III. 


f\  t . 

1 

•     -J 

■■ 

■'       f  1  v 

- 

3w 

■  x 

- 

gj . 

v 

fe^ 


/ 


\ 


rtf 


A 


/ 


E  Miller  del. 


E.C.K&lloes.Mi. 


EXPLANATION     OF     THE     PLATES.  ,  21 


PLATE     IV, 

The  figures  in  this  plate  are  magnified  670  diameters. 

Fig.  1.  Represents  the  blood  corpuscles  of  the  elephant,  red  and 
white,  which  are  the  largest  hitherto  discovered  among  the 
mammalia. 

2.  Exhibits  the  blood  corpuscles  of  the  goat,  both  red  and  white, 

which  are  among  the  smallest  as  yet  made  known  in  the 
class  to  which  they  belong. 

3.  Peculiar  concentric  corpuscles,  taken  twenty-four  hours  after 

death  from  a  polypus  contained  in  the  heart  of  an  old  man. 

4.  A  portion  of  fibrin,  removed  from  a  small  cavity  situated 

beneath  the  buffy  coating  formed  on  some  blood  which  had 
been  abstracted  from  a  woman,  the  subject  of  epileptic  fits, 
and  for  which  she  was  bled;  it  exhibits  the  granular  and 
fibrous  structure,  which  the  spontaneously  coagulable 
element  of  the  blood  invariably  assumes  in  solidifying. 

5.  A   portion  of  fibrin,  constituting  the  buffy  coat,  and  which 

formed  a  thick  membrane  on  the  surface  of  the  blood 
abstracted  from  the  woman  already  alluded  to;  it  exhibits 
more  clearly  the  fibrous  construction  of  the  fibrin,  the  fibres 
being  rendered  more  apparent  by  the  action  of  corrosive 
sublimate,  and  also  some  of  the  white  corpuscles  which  are 
found  usually  in  such  abundance  in  the  so-called  inflamma- 
tory crust.  All  false  membranes  have  a  constitution  pre- 
cisely similar. 

6.  Blood  corpuscles  of  the  earth-worm  in  various  states ;  those 

contained  in  the  lower  half  of  the  circle  represent  them  as 
they  appear  in  the  liquor  sanguinis,  or  plasma,  in  which 
most  of  the  corpuscles  speedily  assume  a  stellate  form,  as 
do  those  of  most  of  the  invertebrate  animals,  and  in  which 
state  they  bear  a  close  resemblance  to  the  hispid  pollen 
granules  of  the  order  Composite;  the  stellate  form  of  the 


22  EXPLANATION  OF  THE  PLATES. 

corpuscles  is  speedily  followed  by  their  considerable  enlarge- 
ment, rupture,  and  disaggregation;  the  corpuscles  repre- 
sented in  the  upper  half  of  the  circle  have  been  acted  upon 
by  water,  in  which  they  quickly  lose  their  radiate  aspect, 
swell,  increase  to  two  or  three  times  their  original  dimen- 
sions, exhibit  their  contained  molecules  more  clearly,  and 
which  may  frequently  be  seen  in  a  state  of  the  greatest 
activity ;  finally,  the  corpuscles  become  deformed  in  shape 
and  burst.  It  may  here  be  remarked,  that  the  blood  of 
most  of  the  Invertebrata  is  colourless,  arising  from  the  fact 
of  their  blood  containing  but  one  form  of  corpuscle,  the 
colourless  blood  corpuscle.  In  the  Annelida,  indeed,  the 
blood  is  red ;  the  colouring  matter,  however,  is  not  contained 
in  the  corpuscle,  but  in  the  plasma. 


Flajte-  IV. 


S.Miller,  del. 


E.C.Ivellogo.lith. 


24  EXPLANATION  OF  THE  PLATES. 

I 


PLATE     V. 

The  figures  in  this  plate  are  magnified  350  diameters. 

1.  Exhibits  the  circulation  in  a  portion  of  the  tongue  of  the 

frog,  the  larger  vessel  is  seen  to  be  accompanied  by  a  nerve, 
as  is  usually  the  case,  and  in  all  the  vessels  are  shown  the 
red  and  white  corpuscles,  with  their  differences  of  form,  size, 
structure,  colour,  and  position;  the  general  direction  and 
appearance  of  the  muscular  fibres,  are  likewise  indicated. 

2.  Represents  the  distribution  of  the  smallest  capillaries  in  the 

web  of  the  foot  of  the  frog,  in  which  it  is  seen  that  the 
blood  corpuscles  circulate  only  in  sing^- series,  the  pigment 
cells,  cellular  tissue  of  the  parenchyma,  and  the  beautiful 
hexagonal  and  nucleated  tessellate  epidermis  are  likewise 
exhibited. 


PlaU  V. 


H. Miller,  del. 


EC.  Kellogg  ltth. 


26  EXPLANATION      OF     THE     PLATES. 


PLATE    VI. 

Fig.  1.  Is  a  more  highly  magnified  representation  of  the  circulation 
in  the  capillaries  of  the  web  of  the  foot  of  the  frog;  in  it 
the  white  and  red  corpuscles  as  well  as  the  epidermis  are 
more  clearly  defined ;  two  of  the  white  corpuscles  are  seen 
to  be  of  an  oval  form,  resulting  from  compression  between 
the  red  blood  discs  and  the  walls  of  the  vessels.  This  figure 
is  magnified  670  diameters. 
2.  Exhibits  a  portion  of  a  larger  vessel  also  taken  from  the  web 
of  the  foot  of  the  frog ;  in  it  the  white  corpuscles  are  seen  to 
have  collected  in  considerable  quantity,  as  they  are  fre- 
quently observed  to  do  after  long  exposure  of  the  web  to 
the  action  of  the  air;  two  cells  or  globules  of  a  very  peculiar 
structure  are  likewise  figured ;  these  open  on  the  surface, 
and  possibly  are  mucous » crypts.  This  representation  is 
magnified  900  diameters. 
4 


Plate,  VI. 


H  Miliei  ael 


:>:.:;:  lifh 


28  EXPLANATION     OF     THE     PLATES. 


PLATE     VII. 

Obs. — It  is  scarcely  necessary  to  observe,  that  the  comparative 
anatomy  figures  are  introduced  in  this  work  for  the  purpose  of  illus- 
trating, in  a  more  satisfactory  manner  than  could  be  otherwise 
accomplished,  certain  points,  especially  the  more  obscure  ones,  con- 
nected with  human  anatomy. 

These  figures  should,  therefore,  by  no  means  be  regarded  as  taking 
the  place  of  any  of  those  which  should  illustrate  human  anatomy,  and 
not  one  of  which,  deemed  to  be  of  importance,  will  on  any  account 
be  omitted;  they  should  be  deemed  not  as  substitutes,  but  as  additions 
to  the  original  design  of  the  work,  and  which  cannot  but  enhance 
very  considerably  its  value. 

Fig.  I.  Represents  a  portion  of  the  under  surface  of  the  tongue  of  the 
frog,  magnified  130  diameters,  and  on  which  are  seen,  first, 
numerous  glands,  mostly  spherical,  and  traversed  by  a  tor- 
tuous vessel,  in  which  the  blood  corpuscles  are  tossed  about 
as  it  were  in  a  vortex ;  and,  second,  mucus  crypts,  the 
apertures  of  which  are  apparent.  Donne  has  observed  these 
bodies,  but  believes  them  to  be  formed  by  nervous  loops,  and 
appears  to  have  overlooked  the  orifices  alluded  to:  these  I 
found  to  be  figured  in  a  drawing  of  the  tongue  of  the  frog, 
sent  me  by  Dr.  Waller,  but  unaccompanied  by  any 
explanation. 

Fig.  2.  A  portion  of  the  same,  magnified  500  diameters,  showing  the 
incurrent  and  excurrent  vessel  of  the  gland,  the  mucous 
crypts,  and  the  net-work  formed  by  the  epithelium. 


Plate  VII. 


H  Miller 


E.C  Kellogg  Mh 


EXPLANATION      OF     THE     PLATES, 


29 


PLATE     IX. 

The  figures  in  this  plate  are  magnified  670  diameters. 

DEVELOPMENT    AND    DISSOLUTION    OE    THE    RED    BLOOD    CORPUSCLE, 

Fig.  1.  Represents  the  development  of  the  red  blood  corpuscle  of  the 
embryo  fowl,  on  the  third  day  of  its  growth,  obtained  from 
one  of  the  vessels  of  the  area  vasculosa:  this  is  seen  to  be  of 
many  different  sizes,  the  smaller  being  scarcely  a  third  the 
volume  of  the  larger  discs,  and  consisting  of  but  little  more 
than  a  nucleus  and  an  envelope.  Numerous  molecules  are 
likewise  visible,  scattered  over  the  field. 
Fig.  2.  The  same,  in  water. 

Fig.  3.  The  red  blood  corpuscles  of  the  adult  fowl,  mostly  in  different 
stages  of  dissolution ;  the  larger  and  deeply  coloured  cor- 
puscles represent  the  fully-developed  discs ;  the  larger  and 
pale  ones,  with  the  distinct  nuclei,  those  the  dissolution  of 
which  has  just  commenced ;  the  smaller  and  colourless  ones, 
red  blood  discs  in  advanced  stages  of  dissolution,  the  sole 
remains  of  which  at  length  is  the  nucleus,  also  represented 
in  the  figure. 
Fig.  4.  The  red  blood  corpuscle  of  the  young  frog  in  different  stages 
of  development.     First,  it  is  seen  as  a  small  and  granular 
body  of  a  circular  form ;  secondly,  it  assumes  an  oval  shape, 
but  still  retains  its  granular  constitution,  and  but  little  exceeds 
its  former  dimensions.     In  this  its  second  stage  of  develop- 
ment, it  is  still  colourless :  it  soon,  however,  grows  in  size, 
and  acquires  a  greater  or  less  degree  of  colouration ;  so  that 
when  it  has  attained  one-half  or  two-thirds  of  its  size,  it  is 
nearly  as  deeply  coloured  as  the  full-grown  blood  disc :  the 
colourless  granular  nucleus  and  the  coloured  and  perfectly 
smooth  outer  portion  of  each  globule  are  not  at  first  distinctly 


30  EXPLANATION  OF  THE  PLATES. 

separated  from  each  other,  the  former  being  at  its  origin 
rather  large,  and  without  any  defined  margin:  it  soon,  how- 
ever, shrinks  in  size,  and  assumes  a  regular  oval  shape. 
Crescentic  bodies,  occasionally  met  with  in  the  blood  of  the 
frog,  and  probably  of  vegetable  nature,  are  also  represented 
in  the  figure. 

Fig.  5.  The  red  blood  corpuscle  of  the  adult  frog,  in  different  stages 
of  dissolution.  In  examining  a  drop  of  the  blood  of  a  full- 
grown  frog,  a  much  greater  uniformity  in  the  size  of  the  red 
blood  discs  will  be  observed,  than  exists  in  that  of  the  very 
young  animal,  fewer  corpuscles  being  in  process  of  develop- 
ment in  the  former  than  in  the  latter. 

Fig.  6.  Blood  corpuscles  of  the  adult  frog  united  into  chains,  an 
arrangement  which  appears  to  be  intimately  connected 
with  the  coagulation  of  the  fibrin. 


Fleets  IX. 


H  Miller. del. 


E-CK.ello64.hth. 


EXPLANATION      OF     TOE     PLATES.  31 


PLATE       X. 

The  figures  in  this  plate  are  magnified  670  diameters. 
DEVELOPMENT   OF   THE   EMBRYO    OE   THE   CHICK 

Fig.  1.  The  appearance  of  the  cicatricula  in  the  yolk  prior  to 
incubation. 

Fig.  2.  The  same  at  the  end  of  the  first  day  of  incubation ;  the  halones 
are  now  distinctly  visible,  as  also  the  area  pellucida,  and 
nota  primitiva,  or  first  rudiment  of  the  young  chick. 

Fig.  3.  The  same  at  the  termination  of  the  thirty-sixth  hour  of  incu- 
bation ;  the  halones  have  become  more  marked  and  expanded, 
the  nota  primativa  larger,  and  traces  of  blood-vessels  are 
now  for  the  first  time  distinctly  visible  in  the  germinal 
membrane. 

Fig.  4.  The  same  at  the  close  of  the  second  day;  the  pulsation  of  the 
heart  and  the  vessels  of  the  area  vasculosa  are  clearly  visible ; 
within  them  the  coloured  corpuscles  may  be  seen  circulating. 

Fig.  5.  The  same  at  the  end  of  the  third  day  of  development;  the 
area  vasculosa  has  now  extended  itself  to  two  or  three  times 
its  former  dimensions. 

Fig.  6.  The  embryo  on  the  conclusion  of  the  fourth  day;  the  head, 
the  eye,  and  the  budding  of  the  allantois  are  now  seen  in 
addition  to  the  parts  previously  noticed. 

Fig.  7.  The  embryo  at  the  termination  of  the  fifth  day ;  the  wing  and 
the  foot  have  made  their  appearance;  the  limits  of  the  area 
vasculosa  cannot  now  be  seen,  it  extending  over  two-thirds 
of  the  surface  of  the  egg;  after  this  and  the  following  day, 
the  periods  of  its  complete  development,  the  area  suffers  an 
arrest  of  growth,  and  the  vessels  contract  and  carry  but 
little  blood,  until  at  length  they  are  entirely  obliterated. 
The  allantois  has  on  this  day  attained  a  considerable  size, 
and  its  further  growth  proceeds  with  the  utmost  rapidity. 


32  EXPLANATION     OF     THE     PLATES. 

Fig.  8.  The  embryo  six  days  old  with  the  allantois  separated  from 
the  area  vasculosa  and  the  yolk,  &c. 

Fig.  9.  The  embryo  of  the  ninth  day  of  development,  seen  through 
the  allantois,  which  now  invests  nearly  the  entire  surface 
of  the  yolk,  and  beneath  which  the  collapsed  and  faintly 
coloured  vessels  of  the  area  vasculosa  may  still  be  discerned. 
The  purpose  fulfilled  by  the  distribution  of  such  innumerable 
vessels  in  the  membrane  of  the  area  vasculosa,  and  subse- 
quently in  the  allantois,  is  but  temporary,  and  is  doubtless 
connected  with  respiration,  the  blood  in  these  vessels  being 
submitted  to  the  influence  of  the  oxygen  of  the  air,  which 
enters  the  egg  through  the  pores  contained  in  its  shell;  the 
vital  fluid  is  thus  regenerated  and  afterwards  reconveyed  to 
the  embryo  itself,  from  which  it  first  proceeded.  At  the 
completion  of  the  development  of  the  chick,  the  allantois 
undergoes  the  same  obliteration  of  its  vessels  which  the  area 
vasculosa  previously  suffered. 

Fig.  10.  The  embryo  at  the  end  of  the  seventh  day  of  development 
removed  from  its  membranes. 

Fig.  11.  The  same  at  the  end  of  the  ninth  day,  also  separated  from 
its  membranes. 

Such  is  a  brief  sketch  of  the  marvellous  development  of  the  embryo 
of  the  chick. 


Plzte,  X. 


Ji. Killer,  del. 


E.C  Hello gg.Iith 


34  EXPLANATION      OF     T  U  E      PLATES, 


PLATE    XI. 

The  figures  in  this  plate  are  magnified  670  diameters. 

MUCUS. 

Fig.  1.  Mucus  corpuscles  of  their  ordinary  size,  form,  and  appearance. 

Fig.  2.  The  same  collapsed,  owing  to  the  density  of  the  fluid  in  which 
they  are  contained;  these  corpuscles  are  capable  of  resuming 
the  circular  form  by  the  addition  of  water. 

Fig.  3.  Represents  the  action  of  water  on  the  mucus  corpuscles,  in 
which  they  increase  very  considerably  in  dimension,  the 
nucleus  which  is  usually  single  becoming  at  the  same  time 
more  distinct. 

Fig.  4.  The  same  acted  on  by  very  dilute  acetic  acid,  under  the 
influence  of  which  the  originally  single  nucleus  becomes 
divided  into  two  parts,  the  portion  of  the  corpuscle  external 
to  these  remaining  granular. 

Fig.  5.  Exhibits  the  action  of  undilute  acetic  acid,  under  which  the 
nucleus  becomes  divided  into  from  two  to  five  or  even  more 
parts,  the  enveloping  portion  of  the  corpuscle  losing  its 
granular  texture,  and  appearing  perfectly  smooth  and 
transparent.  ' 

Fig.  6.  Mucus  corpuscles  in  process  of  development,  expressed  from 
the  cavity  of  a  gland  situated  in  the  mucous  membrane 
lining  the  upper  portion  of  the  rectum  of  a  child  who  died 
of  English  cholera. 


Fh/<  Jl. 


H.Miller,  del. 


E.C.Ivelloa§.litli. 


EXPLANATION     OF     TH.E      PLATES, 


PLATE     XII. 

The  figures  in  this  plate  are  magnified  670  diameters. 
MUCUS. 

Fig.  1.  Represents  an  example  of  vaginal  mucus  obtained  during 
parturition,  and  containing  blood  corpuscles. 

Fig.  2.  Is  a  representation  of  oesophageal  mucus. 

Fig.  3.  Exhibits  the  mucous  corpuscles  contained  in  some  bronchitic 
mucus,  and  obtained  from  a  patient  labouring  under  chronic 
bronchitis.  The  mucus  was  ropy  and  tenacious,  and  many 
of  the  corpuscles  were  rendered  of  an  oval  form  by  the 
pressure  exerted  upon  them  by  the  filaments,  of  which  the 
fluid  portion  of  true  mucus  is  constituted. 

Fig.  4.  Vegetation  contained  in  the  same  mucus  as  that  from  which 
the  previous  figure  was  made. 

Fig.  5.  Mucus  from  the  stomach. 

Fig.  6.  Is  a  representation  of  the  vaginal  tricho-monas  of  Donne\ 
copied  from  the  atlas  appended  to  the  "Cours  de  Micro- 
scopie." 

It  may  here  be  observed  that  the  above  is  the  only  instance  of  a 
copied  figure  being  introduced  into  this  work,  and  that  in  no  case 
where  it  is  possible  to  procure  subjects  for  original  drawings,  will 
copied  ones  be  admitted. 


'Plate  XII. 


H  M  ller.del 


E.C.Kellogg.litL 


38  EXPLANATION      OF     THE      TLATEB 


PLATE    XIII. 

The  figures  in  this  plate  are  magnified  670  diameters. 
PUS. 

Fig.  1.  Is  a  representation  of  an  example  of  laudable  pus  formed  on 
a  granulating  surface  on  the  arm  of  a  child,  the  consequence 
of  a  burn.  In  this  figure,  one  or  two  oil  globules  are  likewise 
introduced. 

Fig.  2.  The  same  acted  on  by  acetic  acid,  and  showing  the  compound 
nuclei. 

Fig.  3.  Pus  corpuscles  treated  with  water,  many  of  them  exhibiting 
but  a  single  nucleus.  This  example  of  pus  was  obtained 
from  a  pustule  formed  around  the  root  of  the  nail,  and  induced 
by  a  prick  received  during  dissection. 

Fig.  4.  Epithelial  scales  remarkable  for  the  great  size  of  their  nuclei, 
and  obtained  from  a  small  pustule  situated  beneath  the  nail 
of  one  of  the  fingers,  and  which  pustule  was  also  the  result 
of  a  prick  received  in  dissecting. 

Fig.  5.  An  example  of  pus  obtained  from  an  old  scrofulous  abscess : 
the  corpuscles  in  it  are  seen  to  be  mostly  broken  up  into  the 
primary  molecules  of  which  they  are  constituted. 

Fiff.  6.  An  example  of  venereal  pus,  showing  the  peculiar  animalcules 
described  by  Donne. 

The  whole  of  the  figures  contained  in  this  and  the  two  preceding 
j 'lates  illustrate  human  microscopic  anatomy. 


T  Late  XIII. 


H.Miller  ael. 


EC.Xelloed.lith. 


40  EXPLANATION     OF     THE      PLATES, 


PLATE     XIV. 

The  figures  in  this  plate  are  magnified  670  diameters. 
MILK. 

Fig.  1.  The  globules  of  the  healthy  milk  of  a  woman. 

Fig.  2.  The  globules  contained  in  impoverished  human  milk,  which 
are  seen  to  be  smaller  in  size  and  fewer  in  number  than  in 
ordinary  milk. 

Fig.  3.  An  example  of  colostrum,  on  the  first  day,  obtained  from  a 
young  woman  aged  nineteen,  delivered  of  her  first  child,  and 
showing  the  size  and  arrangement  of  the  ordinary  milk  glob- 
ules, as  well  as  the  structure  and  appearance  of  the  peculiar 
colostrum  corpuscles. 

Fig.  4.  The  same  colostrum  of  the  same  age,  containing  a  greater 
number  of  the  colostrum  corpuscles. 

Fig.  5.  The  same  colostrum,  on  the  same  day,  exhibiting  the  great 
size  of  the  cream  globules,  which  appear  frequently  to  pre- 
sent rather  the  aspect  of  oil  than  that  of  true  milk  globules. 

Fig.  6.  The  milk  globules  aggregated  into  masses,  as  occurs  in  cases 
of  engorgement  of  the  breast. 


7CLt&  XIV. 


42  EXPLANATION     OF     THE     I'  L  A  T  E  8 , 


PLATE     XV. 

The  figures  in  this  plate  are  magnified  670  diameters. 
MILK. 

Fig.  1.  An  example  of  pus  in  the  milk  of  woman. 
Fig.  2.  The  same  of  the  blood  corpuscles  in  human  milk. 
Fig.  3.  The  appearance  of  the  milk  after  treatment  by  ether. 
Fig.  4.  The  same  after  the  application  of  acetic  acid. 
Fig.  5.  Caseine  precipitated  from  the  filtered  serum  by  acetic  acid. 
Fig.  6.  A  specimen  of  the  milk  of  the  cow  in  which  adulteration  with 
starch  was  revealed  by  treatment  with  the  iodide  of  potassium. 

For  many  of  the  examples  of  human  milk  upon  which  my  observa- 
tions were  made,  and  from  which  several  of  the  figures  were  prepared, 
I  am  indebted  to  the  kindness  of  Dr.  Robert  Barnes,  District  Surgeon 
to  the  Queen  Adelaide  Lying-in  Hospital. 

6 


Plate,  XK 


H.liiilev.dei. 


E.C.KeHoPB.lith. 


44  EXPLANATION      OF      r  H  E     PLATES 


PLATE    XVI. 


SEMEN. 


Fig.  1.  The  spermatic  animalcules  and  "seminal  granules  ,;  contained 
in  the  human  semen  as  ejaculated,  magnified  900  diameters, 
and  to  which  are  added  several  sperm atophori,  magnified  to 
the  same  extent,  and  introduced  to  render  the  representation 
of  the  development  of  the  spermatozoa  of  man  more  com- 
plete. The  larger  seminal  granules  mostly  contained  a 
single  distinct  nucleus,  which  renders  it  probable  that  they 
are  spermatophori  in  progress  of  development. 

Fig.  2.  Represents  the  several  stages  of  evolution  of  the  spermatic 
animalcules  of  certhia  familiaris  (common  creeper) ;  I,  an 
adult  spermatozoon,  taken  from  the  orifice  of  the  vas  defer- 
ens ;  a.  seminal  granule,  procured  from  a  very  collapsed 
testicle  in  the  winter  season ;  b  to  k.  spermatophori  in  differ- 
ent stages  of  development,  taken  from  a  testicle  in  summer, 
during  turgescence.     Magnified  900  diameters. 

This    figure    is    copied    from    Wagner's    "  Elements    of   Special 
Physiology." 


Tla/r  XVI. 


S  Miller  del. 


E.CKeL 


46  EXPLANATION     OF     THE      PLATES, 


PLATE    XVIII. 

The  figures  in  this  plate  are  magnified  130  diameters. 
FAT. 

Fig.  1.  A  portion  of  the  great  omentum  of  a  child  aged  seven  years. 
The  fat  cells  are  seen  to  be  small,  perfectly  globular,  and 
aggregated  into  clusters,  which  lie  near  to  and  in  the  course 
of  the  blood-vessels. 

Fig.  2.  A  portion  of  the  fat  of  an  adult  taken  from  over  the  gluteus 
muscle.  The  fat  cells  in  it  are  observed  to  be  of  larger 
size,  and  many  of  them  are  polyhedral ;  these  cells  are  also 
seen  to  be  held  in  union  by  an  enclosing  membrane  of  cellu- 
lar tissue. 


Plate  ZV1II. 


E  Miller,  del. 


E.C.Kello^.lith. 


48  EXPLANATION      OF     THE     PLATES. 


PLATE    XIX. 

The  figures  in  this  plate  are  magnified  130  diameters. 
PAT. 

Fig.  1.  Fat  vesicles  of  the  pig,  in  which  the  appearance  of  a  nucleus 
was  produced  by  moderate  compression  between  two  plates 
of  glass. 

Fig.  2.  The  fat  vesicles  of  the  pig,  ruptured  by  compression  between 
two  plates  of  glass:  the  contents  of  the  cells  are  seen 
escaping  from  their  enclosing  membranes. 

Fig.  3.  Fat  cells,  forming  part  of  the  marrow  contained  in  the  femur 
of  a  child  aged  about  ten  years;  in  these  a  large  nucleus-like 
body  is  visible,  the  formation  of  which  probably  depended 
upon  a  change  in  the  condition  of  the  contents  of  the  cells 
induced  by  decomposition. 

Fig.  4.  The  same  cells  in  a  further  stage  of  decomposition:  the 
membranes  of  the  cells  have  become  ruptured,  and  are 
clearly  seen  broken  and  empty,  lying  beside  their  escaped 
contents,  which  either  become  broken  up,  and  assume  the 
form  of  drops  of  oil  of  different  sizes,  or  remain  entire,  in 
which  case  they  frequently  exhibit  the  crystalline  appearance 
portrayed  in  figure  5. 

Fig.  5.  Human  fat  vesicles,  on  the  surface  of  which  crystals,  supposed 
to  be  those  of  margaric  acid,  radiating  from  a  centre,  have 
appeared :  their  presence  is  to  be  regarded  as  an  indication 
that  decomposition  has  begun  to  affect  the  contents  of  the 
cells. 

Fig.  6.  Fat  cells,  contained  in  a  small  melicerous  tumour  removed 
from  over  the  nasal  bones,  in  all  of  which  a  nucleus-like 
body  was  clearly  visible. 

The  tumour  from  which  the  figure  was  taken  was  kindly  forwarded 
for  examination  by  Mr.  Ransom,  of  the  University  College  Hospital. 


Plate  XIX. 


H  Miller  del. 


£  C.Kellog§,lifll. 


50  EXPLANATION     OF     THE     PLATES 


PLATE    XX. 

The  figures  in  this  plate  are  magnified  670  diameters. 

Fig.  1.  Buccal  epithelial  cells  in  different  stages  of  development,  from 
their  earliest  condition,  in  which  they  bear  the  form  of 
mucous  corpuscles,  to  their  fully  developed  state.  For  a 
representation  of  the  epithelial  cells  of  the  vagina  and 
oesophagus,  see  Plate  ^Lll.figs.  1  and  2. 

Fig.  2.  Cylindrical  or  cuneiform  epithelial  cells,  taken  from  the  duode- 
num of  a  child  seven  days  old :  those  of  the  adult  are  in 
every  respect  identical;  the  group  of  angular  cells  at  the 
inferior  part  of  the  figure  represents  the  summits  of  the 
cuneiform  epithelial  cells. 
7 


FlateXX. 


filler  del. 


E.C  Kellosje.lith. 


EXPLANATION      OF     THE     PLATES.  51 


PLATE    XXI. 

The  figures  in  this  plate  are  magnified  670  diameters. 

Fig.  1.  Ciliary  epithelium  from  the  trachea  of  the  frog:  it  will  be  seen 
that  the  form  of  the  cells  is  very  different  from  that  of 
mammalia. 

Fig.  2.  Human  ciliary  epithelium  contained  in  the  fluid  expressed 
from  a  portion  of  lung  taken  from  its  extreme  periphery, 
and  apparently  consisting  of  air  cells  alone.  It  is  mixed  up 
with  cells  of  tesselated  epithelium. 

Fig.  3.  Human  ciliary  epithelium  from  the  trachea;  both  side  and 
end  views  of  the  cells  are  given. 

Fig.  4.  Tesselated  epithelium  from  the  tongue  of  the  frog. 

Fig.  5.  Tesselated  epithelium  from  the  tongue  of  the  Triton:  the 
nuclei  are  seen  to  be  very  large,  their  great  size  affording  an 
illustration  of  the  law  which  has  already  been  announced, 
viz:  that  all  the  corpuscular  elements  of  the  animal  organi- 
zation, whether  those  of  the  epithelium,  the  glands,  cartilages 
or  muscles,  stand  in  relation  with  the  dimensions  of  the  blood 
discs;  where  these  are  large,  ihe  other  corpuscles  are  formed 
on  a  similar  relative  scale. 

It  is  probable  that  the  law  admits  of  extension,  and  that  all  the  elements 
of  the  animal  structure  bear  a  relation  in  size  to  the  red  blood  discs. 

Mr.  John  Quekett  made  the  interesting  observation,  some  time  since, 
that  the  relative  size  of  the  lacunaB  of  bone  corresponded  with  that 
of  the  blood  corpuscles,  a  further  illustration  of  the  accuracy  of  the 
law  referred  to. 

Wishing  to  test  the  truth  of  this  law  in  as  satisfactory  and  conclu- 
sive a  manner  as  possible,  I  applied  to  Professor  Owen  for  a  specimen 


52  EXPLANATION      OF     T  li  E     I'  L  A  T  E  S . 

of  the  Siren  or  Proteus,  animals  remarkable  for  the  dimensions  of 
their  blood  discs,  and  that  gentleman  kindly  placed  at  my  disposal  an 
example  of  the  Meno-branchus  lateralis,  a  member  of  the  same 
perenni-branchiate  group,  and  the  blood  corpuscles  of  which  "are 
rather  larger  than  those  of  the  Proteus,  but  not  so  large  as  those  of 
the  Siren."  In  this  animal  I  found,  as  I  had  anticipated,  that  the 
soundness  of  the  law  was  fully  maintained. 

The  law  announced  would  doubtless  be  cited  by  those  physiologists 
who  enterts:n  the  idea  that  all  the  corpuscular  elements  of  the  animal 
fabric  proceed  from  the  red  blood  disc,  as  a  proof  of  the  truth  of  their 
theory,  against  which,  however,  I  conceive  that  sound  and  conclusive 
arguments  may  be  urged. 


PI  a/ r- XXI. 


TT.Miller.de!. 


E.G.T(e]lo66.1itli. 


54  EXPLANATION      OF     THE     P  L  A  T  E  S  , 


ALL    THE    FIGURES    IN    THIS    PLATE    ARE    HITMAN. 

PLATE    XXII. 

The  figures  in  this  plate  are  magnified  670  diameters. 

Fig.  1.  Tesselated  epithelium  from  the  serous  coat  of  the  liver;  from 
some  of  the  cells  the  nuclei  have  escaped. 

Fig.  2.  Ditto  from  the  choroid  plexus ;  the  spines  described  by  Henle 
as  proceeding  from  the  angles  of  the  cells  must  be  of  unusual 
occurrence,  as  I  have  never  yet  seen  them. 

Fig.  3.  Ditto  from  the  vena  cava  inferior  in  different  stages  of  devel- 
opment, from  the  white  corpuscle  of  the  blood  upwards. 

Fig.  4.  Ditto  of  the  arch  of  the  aorta;  some  of  the  cells  are  seen  to 
have  lost  their  nuclei. 

Fig.  5.  Ditto  from  the  surface  of  the  uterus  of  a  woman  who  died 
suddenly  during  lactation. 

Fig.  6.  Ditto  from  the  internal  surface  of  the  pericardium. 


PhuXKIT. 


H.MfllKi-.iiel. 


—      Kellood.  lith. 


56  EXPLANATION     OF     THE     PLATES. 


PLATE     XXIII. 

Fig.  1.  Upper  surface  of  epidermis,  raised  by  means  of  a  blister 
from  over  the  region  of  the  heart  of  a  woman :  it  exhibits 
the  cellular  constitution  of  the  epidermis,  the  papillae  and 
apertures  of  the  sebaceous  and  sudoriferous  glands.  130 
diameters. 

Fig.  2.  The  under  surface  of  the  same,  exhibiting  the  infundibuliform 
processes  of  the  epidermis  sent  down  to  the  sebaceous  and 
sudoriferous  glands.     130  diameters. 


Flate  XXIII. 


H  Miller, del. 


3.  C.Kello^  Mi. 


58  EXPLANATION      OF      THE     PLATES. 


PLATE    XXIV. 

STRUCTURE   OF   EPIDERMIS. 

Fig.  1.  A  portion  of  the  epidermis  of  the  palm  of  the  hand,  magnified 
with  a  simple  lens,  showing  the  direction  of  the  rugae  in 
that  situation,  and  the  arrangement  of  the  apertures  of  the 
sudoriferous  glands.  Each  of  the  ridges  figured  is  made  up 
of  square  compartments,  the  divisional  lines  of  which  run  at 
right  angles  to  the  ridges,  passing  across  the  apertures  referred 
to.  These  several  compartments  again  are  indented  on  their 
under  surface  with  the  papillae  of  the  sensitive  skin. 

Fig.  2.  A  portion  of  the  same,  magnified  100  diameters. 

Fig.  3.  A  transverse  section  of  the  ridges  of  the  epidermis  of  the  palm 
of  the  hand,  showing  a  side  view  of  the  apertures  of  the 
sudoriferous  glands,  their  spiral  ducts,  the  thickness  of  the 
epidermis  in  the  situation  mentioned,  its  composition  of 
super-imposed  layers  of  cells,  and  its  mode  of  connexion 
with  the  true  skin.     100  diameters. 

Fig.  4.  A  longitudinal  section  of  one  of  the  ridges,  magnified  to  the 
same  extent  as  the  previous  figure,  viz:  100  diameters:  in 
this  the  composition  of  the  thickened  epidermis  of  adherent 
layers  of  cells  is  better  seen,  and  the  difference  in  the  form 
of  the  superficial  and  deeper  seated  cells  may  also  be 
observed. 

Fig.  5.  A  portion  of  the  epidermis  removed  from  the  back  and  outer 
part  of  the  hand,  showing  the  disposition  of  the  folds  in  that 
situation,  the  arrangement  of  the  papillae,  the  disposition  of 
the  hair  follicles  and  hairs,  and  the  apertures  of  the  sudorif- 
erous and  sebaceous  glands.     Magnified  with  a  simple  lens. 

Fig.  6.  A  piece  of  the  same,  magnified  100  diameters,  showing  that 
each  line  is  a  furrow  or  groove,  a  provision  which  allows  of 
a  very  great  extension  of  the  epidermis. 
8 


Plate  XXIV. 


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E.C.Kellodo.Mi 


60  EXPLANATION     OF     THE     P  L.  A  T  E  S  , 


PLATE     XXV. 


STRUCTURE   OF   NAILS. 


Fig.  1.  A  longitudinal  section  of  the  nail  of  the  middle  finger,  magni- 
fied 130  diameters,  showing  the  direction  of  the  striae  or 
laminae  of  cells  of  which  the  nail  is  composed,  and  which 
usually  pass  from  above  downwards  and  forwards.  In  the 
section  shown  in  the  figure,  the  obliquity  of  the  striae  is  but 
slight;  the  under  surface  of  the  nail  is  distinguished  from 
the  upper  by  its  smooth  outline. 

Fig.  2.  The  same,  in  which  the  striae  are  disposed  more  obliquely, 
but  in  a  contrary  and  unusual  direction;  viz:  from  above 
downwards  and  backwards.     130  diameters. 

Fig.  3.  Other  longitudinal  sections,  in  one  of  which  the  striae  run, 
almost  vertically.     130  diameters. 

Fig.  4.  A  transverse  section  of  nail,  magnified  to  the  same  extent  as 
the  former  figures ;  in  it  the  striae  are  parallel  to  the  surface, 
and  are  less  strongly  marked. 

Fig.  5.  The  detached  cells  of  which  the  super-imposed  layers  of  nails 
are  composed;  the  smaller  cells  are  magnified  130  diameters, 
the  larger  670. 

Fig.  4.  Plate  XXVI.  represents  the  peculiar  and  beautiful  manner  in 
which  the  nail  and  the  papillary  layer  of  the  true  skin  are 
united. 


PlateXXV. 


H  Miller  del  ad  nat. 


E.G.Kelloda.lith 


EXPLANATION       OF      THE      PLATES. 


01 


PLATE    XXVI. 

STRUCTURE   OF    EPIDERMIS,   ETC. 

Fig.  1.  A  portion  of  epidermis  taken  from  the  back  and  outer  part  of 
the  hand,  magnified  100  diameters,  and  viewed  on  its  upper 
surface,  showing  the  elevations  by  which  it  is  marked,  and 
which  are  produced  by  the  papillae  of  the  true  skin. 

Fig.  2.  The  same  viewed  on  the  under  surface,  showing  the  depres- 
sions occasioned  by  the  papillae.  The  number  of  apertures 
of  the  ducts  of  the  sudoriferous  and  sebaceous  glands  is,  in 
reference  to  that  of  the  papillae,  about  one  of  the  former  to 
six  or  seven  of  the  latter.     100  diameters. 

Fig.  3.  A  portion  of  epidermis,  magnified  100  diameters,  removed  from 
over  the  pubis  of  a  woman,  and  displaying  the  apertures  of 
the  hair  follicles,  and  the  manner  in  which  the  hairs  issue 
from  them.  Some  of  the  follicles  contain  but  a  single  hair, 
others  two  or  even  three:  it  is  probable  that  this  last  is  the 
normal  number  of  hairs  enclosed  in  each  follicle  wherever 
situated,  but  which  in  the  adult  is  not  generally  encountered 
in  consequence  of  the  continual  removal  to  which  hairs  are 
subject.  It  is  about  the  apertures  of  the  hair  follicles  that 
the  scurf  is  formed,  and  concerning  which  a  very  erroneous 
notion  prevails,  viz:  that  it  is  constituted  of  desquamated 
epidermis.  Scurf  does  not  in  the  least  exhibit  the  structure 
of  epidermis,  but  simply  consists  of  the  inspissated  secretion 
of  the  sebaceous  glands,  and  many  of  which,  opening  into 
the  hair  follicles,  account  for  its  collection  around  their 
orifices. 

Fig.  4.  A  transverse  section  of  the  nail  of  the  middle-toe  of  an  adult, 
magnified  100  diameters,  showing  its  lamellated  structure, 


62  EXPLANATION     OF     THE     PLATES. 

and  the  mode  of  its  connexion  with  the  papillary  layer  of 
the  dermis  by  mutually  inter-locking  processes.  This  mode 
of  union  is  excessively  firm,  and  is  precisely  that  employed 
by  carpenters,  and  known  by  the  appellation  of  "dovetailing." 

Fig.  5.  A  portion  of  epidermis  removed  from  the  back  of  the  neck  by 
means  of  a  blister,  and  magnified  670  diameters.  The 
younger  cells  are  seen  to  be  filled  with  a  straw-coloured 
fluid,  the  serum  extracted  through  the  agency  of  the  vesicant. 

Fig.  6.  a.  Some  detached  cells  of  epidermis,  obtained  by  scraping  the 
sole  of  the  foot,  magnified  670  diameters.  Cells  in  a  similar 
state  exist  beneath  the  nails,  around  the  nipple,  and  on  the 
surface  of  the  body  of  new-born  children  where  the  creamy 
scum  formed  by  them  and  inter-mingled  with  fatty  matter 
poured  out  by  the  sebaceous  glands  has  been  named  Vernix 
caseosa.  (See  c.) — b.  Cells  of  some,  magnified  130  diame- 
ters.— d.  Cells  of  epithelium  from  the  mouth  of  the  Meno- 
branchus  lateralis:  they  are  introduced  for  the  purpose  of 
showing  the  accuracy  of  the  law  of  the  relation  in  size  of 
the  several  elements  entering  into  the  composition  of  the 
animal  frame. — e.  Two  or  three  epithelial  cells  of  the  lateral 
ventricles  of  the  brain.  I  have  recently  ascertained  that 
the  epithelium  of  the  frontal  sinuses  is  as  stated,  ciliated.  I 
cannot  help  suspecting,  however,  that  it  is  not  in  all  cases 
so.  No  amount  of  care  has  succeeded  in  the  detection  of 
ciliary  epithelium  in  the  ventricles  of  the  brain.  The  epi- 
dermis of  tritons  and  frogs  consists  of  hexagonal,  translucent, 
and  adherent  cells,  containing  distinct  granular  nuclei. 


Plate.  XXVI. 


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04  EXPLANATION     OF     THE     PLATES 


PLATE     XXVII. 

PIGMENT   CELLS. 

Fig.  1.  Pigment  cells  and  granules  taken  from  off  the  inner  surface  of 
the  choroid  membrane  of  the  human  eye,  magnified  670 
diameters. 

Fig.  2.  The  pigment  cells  of  the  inner  surface  of  the  choroid  of  the 
eye  of  the  pig,  magnified  350  diameters. 

Fig.  3,  Displays  the  linear  and  branched  disposition  of  the  stelliform 
pigment  cells  of  the  lamina  fusca  of  the  eye  of  the  pig-  A 
similar  disposition  of  these  cells  also  exists  in  the  human  eye, 
but  in  light-coloured  eyes  is  not  strongly  marked:  the 
branches  commence  on  the  posterior  part  of  the  lamina, 
miscalled  fusca,  since  in  some  instances  it  is  jetty  black, 
are  at  first  thick  and  closely  arranged;  as  they  approach 
the  anterior  part  of  the  eye,  however,  they  diminish  in  size, 
and  are  separated  by  distinct  intervals.  This  figure  is 
magnified  100  diameters. 

Fig.  4.  a.  Human  stelliform  pigment  cells  of  the  eye,  magnified  350 
diameters,  b.  Pigment  cells  of  the  skin  of  the  negro, 
enlarged  670  diameters,  c.  Pigment  cells  from  the  lungs, 
magnified  to  the  same  extent. 

Fig.  5.  A  portion  of  the  epidermis  of  the  negro,  magnified  350  diame- 
ters, and,  viewed  on  its  under  surface,  the  pigment  cells  are 
seen  to  be  collected  principally  in  the  furrows  which  exist 
between  the  papillae,  the  depressions  produced  by  which  are 
also  represented  in  the  figure, 

Fig.  6.  A  portion  of  the  epidermis  removed  from  the  areola  around 
the  nipple  of  a  woman  recently  delivered,  and  also  viewed 
upon  its  under  surface.  It  is  seen  to  differ  solely  from  the 
epidermis  of  the  negro  in  the  smaller  number  of  pigment 
cells  contained  in  it.     350  diameters. 

Obs.  Pigment  cells  and  granules  frequently  exist  in  the  fibres  of 
the  external  surface  of  the  sclerotic  of  some  animals,  as  the  pig;  and 
it  is  probable  that  in  some  instances  they  may  be  found  in  those  of 
the  eye  of  man. 


Hate,  XXVII, 


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66  EXPLANATION  OF  THE  PLATES. 


PLATE     XXVIII. 


STRUCTURE    OF   HAIR. 


Fig.  1,  Shows  the  structure  and  depth  of  implantation  of  the  entire 
root  of  a  hair  of  the  scalp,  magnified  130  diameters:  it  dis- 
plays the  two  sheaths  which  include  the  stem,  and  its  dilated 
extremity,  the  bulb,  and  which  is  seen  to  rest  upon  a  distinct 
cellular  vesicle;  the  outer  sheath  completely  surrounds  the 
base  of  the  hair,  and  cuts  it  off  from  all  direct  vascular  sup- 
ply; the  vessels,  however,  which  nourish  the  hair  are  seen 
to  ramify  on  the  external  surface  of  this  sheath,  which  is 
also  observed  to  be  surrounded  by  fat  vesicles,  the  r§ot  hav- 
ing passed  through  the  thickness  of  the  skin,  and  imbedded 
itself  in  the  sub-cutaneous  and  fatty  cellular  tissue. 

Fig.  2.  The  root  of  a  gray  hair  forcibly  removed  from  the  scalp ;  in 
this  the  outer  sheath  is  seen  to  be  broken  off  just  above  the 
place  at  which  the  stem  begins  to  dilate  into  the  bulb;  a 
similar  rupture  almost  invariably  occurs  in  the  outer  sheath 
of  all  hairs,  whether  coloured  or  uncoloured,  which  are 
forcibly  uprooted.  The  contrast  between  the  coloured  and 
the  uncoloured  hair  is  striking.     130  diameters. 

Fig.  3.  The  cells  of  which  the  outer  sheath  is  composed,  magnified 
670  diameters. 

Fig.  4.  A  portion  of  the  inner  sheath,  seen  on  its  inner  surface,  and 
magnified  350  diameters;  this  is  lined  with  a  layer  of  elon- 
gated and  nucleated  cells;  the  outer  portion  of  this  sheath  is 
distinctly  fibrous,  the  fibres  being  formed  out  of  the  cells,  the 
nuclei  of  which  become  absorbed:  the  inner  surface  also 
exhibits  transverse  markings,  the  impressions  of  the  scales 
of  the  stem  of  the  hair. 

Fig.  5.  Some  of  the  pigment  cells,  of  a  multitude  of  which  the  bulb 
of  the  hair  is  composed :  magnified  670  diameters. 


Tlate,  XXVIII. . 


■ 


v . 


i 


«* 


H.MilLer,  deladnat. 


E.C.Kellogt.Mi. 


68  EXPLANATION      OF     THE     PLATES. 


PLATE    XXIX, 


STRUCTURE   OP    HAIR. 


Fig.  1.  A  portion  of  the  stem  of  a  gray  hair  of  the  scalp,  magnified 
350  diameters,  showing  the  medullary  canal,  the  fibres  of 
the  stem,  and  the  outer  imbricated  scales. 

Figs.  2,  3.  Transverse  sections  of  hairs  of  the  beard:  magnified  130 
diameters. 

Fig.  4.  The  fibres  of  the  stem  of  a  hair,  magnified  670  diameters. 
It  is  most  probable  that  these  fibres  originate  in  the  same 
way  as  those  of  the  inner  sheath,  viz:  in  nucleated  cells. 

Figs.  5,  6,  7.  Apices  of  hairs:  figs.  6  and  7  represent  the  points  of 
two  hairs  of  the  scalp,  magnified  350  diameters;  and  fig.  5 
that  of  one  of  the  perineeum.  All  hairs  taken  from  this 
region,  as  well  as  those  of  the  axilla,  present  similar  obtuse 
extremities,  which  probably  result  from  the  constant  friction 
to  which  they  are  subject  in  those  situations. 

Figs.  8,  9,  represent  the  roots  of  two  hairs  of  the  scalp,  removed  with 
the  comb;  the  sheaths,  vesicle,  and  lower  portion  of  the 
bulb  having  remained  behind.  All  hairs  removed  with  the 
comb  and  brush  present  the  same  appearances,  that  of  fig. 
8  being  by  far  the  most  common  form:  magnified  130 
diameters. 

Fig.  10.  A  hair  from  the  whisker,  magnified  130  diameters,  and  con- 
taining two  medullary  canals. 


Route,  XXIX. 


7  I  6  1 


ff    F 


10 


H.Miller,  deladnat. 


E.C.Xeflogg.lith. 


70  EXPLANATION     OF     THE     PLATES. 


PLATE    XXX. 

STEUCTI7EE   OF   CAETIIAGE. 

Fig.l.  A  transverse  section  of  the  cartilage  of  a  rib,  magnified  350 
diameters,  showing  the  perichondrium  and  the  compressed 
cells  of  the  margin  of  the  cartilage.  It  is  most  probable 
that  it  is  in  the  space  between  the  perichondrium  and  the 
external  surface  of  the  rib  that  the  chief  development  of 
new  cells  takes  place. 

Fig.  2.  A  transverse  section  of  the  same,  showing  the  parent  cells, 
which  are  situated  more  deeply  in  the  cartilage  of  the  rib. 
350  diameters. 

Fig.  3.  A  vertical  section  of  the  articular  cartilage  of  the  head  of  the 
first  phalanx  of  the  second  finger,  including  also  a  portion  of 
the  bone,  the  cancelli  of  which  contain  numerous  bone  cells, 
and  the  spaces  between  which  are  filled  with  fat  vesicles: 
magnified  130  diameters. 

Fig.  4.  A  vertical  section  of  the  outer  part  of  an  inter- vertebral  car- 
tilage, including  a  portion  of  the  bone.  But  few  corpuscles, 
and  these  for  the  most  part  calcified,  occur  in  the  outer  part 
of  these  cartilages:  the  medullary  cells  of  the  bone  are  seen 
to  be  filled  with  fat  vesicles,  granular  nucleated  cells,  and 
effused  blood  corpuscles.  It  sometimes  happens  that  a  layer 
of  true  articular  cartilage  is  formed  on  the  surface  of  the 
bone,  and  then  the  fibres  of  the  fibro-cartilage  take  their 
origin  from  it,  and  not  from  the  bone  itself:  80  diameters. 


Plate,  XXX 


\  .     m::--^m 


mm  </ 


wk  wiM-f 


^11P!1I11 


E.  Miller,  del  ad  nat. 


E.C  Kellogg. lith 


72  EXPLANATION     OF     THE     PLATES. 


PLATE     XXXI. 

STRUCTURE   OF   CARTILAGE. 

Fig.  1.  A  thin  transverse  section  of  the  cartilage  of  the  concha  of 

the  ear:  magnified  350  diameters. 
Fig.  2.  The  cells  of  the  centre  of  an  inter-vertebral  cartilage  in  the 

different  stages  of  their  development.     350  diameters. 
Fig.  3.  A  longitudinal  section  of  the  cartilage  and  bone  of  the  rib  of 

an  adult,  showing  the  mode  of  union  between  the  two: 

magnified  130  diameters. 
Fig.  4.  A  transverse  section  of  one  of  the  rings  of  the  trachea;  in 

these  the  cells  are  so  closely  aggregated  that  but  little  room 

is   left   between    them    for    inter-cellular    substance:    350 

diameters. 
Fig.  5.  A  transverse  section  of  the  thyroid  cartilage  of  a  young  man, 

eighteen  years  of  age,  in  which  fibres  analogous  to  those 

of  the  fibro-cartilages  have  made  their  appearance:    130 

diameters. 


Ftat&XKXI. 


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74  EXPLANATION  OF  THE  PLATES, 


PLATE    XXXII 


STRUCTURE  OF   BONE. 


Fig.  1.  A  transverse  section  of  ulna,  magnified  60  diameters,  showing 
the  Haversian  canals,  the  difference  in  the  size  of  those  sit- 
uated on  the  outer  and  inner  portions  of  the  section,  the 
systems  of  the  lamellae  by  which  each  canal  is  surrounded, 
and  the  bone  cells  placed  between  the  lamellae. 

Fig.  2.  Cross-section  of  Haversian  canals,  magnified  220  diameters, 
showing  the  lamellae,  and  the  bone  cells  with  their  anasta- 
mosing  canaliculi  more  distinctly. 

Fig.  3.  The  same,  still  more  highly  magnified,  viz:  670  diameters. 

Fig.  4.  Longitudinal  section  of  long  bone,  magnified  about  40  diame- 
ters, showing  the  Haversian  canals,  seen  lengthways,  the 
direction  of  the  lamellae  and  the  bone  cells. 
10 


P//U.c  XXXII. 


H.  Miller  del.adnat. 


l;  C  Kellodg,  lirti. 


76-  EXPLANATION      OF     THE     PLATES. 


PLATE    XXXIII. 

STRUCTURE   AND   DEVELOPMENT   OF   BONE. 

Fig.  1.  Parietal  bone  of  human  fetus,  aged  about  two  months,  mag- 
nified 30  diameters. 

Fig.  2.  A  portion  of  the  same,  magnified  60  diameters,  showing  the 
bone  cells  in  process  of  development,  some  of  which  are 
seen  lying  loose  in  the  spaces  between  the  spicula,  and 
which  were  destined,  eventually,  to  become  included  in  the 
ossific  deposition. 

Fig.  3.  Spicula  of  bone  of  a  foetal  humerus,  showing  the  gradual 
deposition  of  the  bony  matter  in  the  meshes  of  fibrous  tissue, 
and  altogether  independently  of  cartilage,  magnified  350 
diameters. 

Fig.  4.  Lamina  of  a  long  bone,  magnified  500  diameters,  drawn  from 
a  preparation  kindly  placed  at  the  author's  disposal  by  Dr. 
Sharpey,  by  whom  the  structure  figured  was  first  described. 

Fig.  5.  Cancelli  of  one  of  the  long  bones  of  a  human  fetus,  magnified 
350  diameters,  showing  the  vast  numbers  of  granular  cor- 
puscles which  the  medullary  cells  of  bone  of  every  age  con- 
tain, but  which  are  especially  abundant  in  fetal  bones;  the 
larger  cells  are  magnified  750  diameters. 

Fig.  6.  Cross-section  of  the  femur  of  a  pigeon,  fed  for  twenty-four 
hours  upon  madder.  This  drawing  was  made  from  a  beau- 
tiful preparation  belonging  to  Mr.  Tomes,  and  lent  me  by 
that  gentleman.     Magnified  220  diameters. 


Ficu&xxxin. 


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E.C.KeUo^.litli. 


78  EXPLANATION     OF     THE     PLATE 


PLATE     XXXIV. 


DEVELOPMENT   OF   BONE. 


Fig.  1.  Longitudinal  section  of  the  epiphysis  and  a  portion  of  the 
shaft  of  a  foetal  femur  at  the  ninth  month,  magnified  100 
diameters,  and  showing  the  columnar  arrangement  of  the 
cartilage  cells,  together  with  the  increased  size  of  the  lower 
cells,  and  the  invading  spicula  of  the  newly-formed  bone. 

Fig.  2.  Transverse  section  of  primary  cancelli,  magnified  350  diame- 
ters, showing  the  included  nuclei  of  cartilage  cells  contained 
in  the  medullary  cells  or  spaces. 

Fig.  3.  Transverse  section  of  primary  cancelli,  magnified  to  the  same 
extent  as  the  last  figure,  in  a  more  advanced  stage  of  their 
formation,  many  of  the  first  formed  cancelli  or  septa  having 
been  absorbed,  as  well  as  the  cell  wall  of  the  cartilage  cor- 
puscles themselves. 

Fig.  4.  Longitudinal  section  of  the  epiphysis  and  a  portion  of  the 
shaft  of  a  foetal  femur  at  the  ninth  month,  magnified  350 
diameters. 


Plate  XXXI] 


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H  Miller  iel.ai.naf. 


E  C.Kellody.lith. 


80  EXPLANATION      OF     THE      PLATES. 


PLATE    XXXV, 


DEVELOPMENT    OF    BONE. 


Fig.  1.  A  transverse  section  of  the  cartilaginous  epiphysis  of  the  lower 
end  of  humerus,  magnified  30  diameters,  showing  the  aper- 
tures of  the  canals  by  which  it  is  traversed. 

Fig.  2.  The  same  in  connexion  with  the  bone :  in  this  figure  it  will 
be  observed  that  there  are  fewer  canals,  that  these  are  of 
larger  calibre,  and  that  the  cartilage  cells  are  disposed 
around  them  in  a  radiate  manner  in  groups.     30  diameters. 

Fig.  3.  One  of  the  apertures  of  the  canal,  more  highly  magnified,  330 
diameters,  showing  more  clearly  the  arrangement  of  the  cells 
around  it,  the  contents  of  the  canal  being  granular  corpuscles 
and  blood-vessels,  as  well  as  the  fact  that  the  inter-cellular 
spaces  nearest  to  the  opening  are  the  last  to  become  con- 
verted into  bone:  in  most  of  the  medullary  spaces  of  the 
second  tier,  the  granular  corpuscles  have  already  made  their 
appearance,  the  cartilage  cells  having  been  removed  by 
absorption. 

Fig.  4.  The  blood-vessels  of  the  medullary  cells  of  a  young  bone  near 
the  epiphysis  injected.  For  the  specimen  from  which  this 
figure  was  drawn  I  am  indebted  to  the  kindness  of  Mr 
Quekett,  of  the  Royal  College  of  Surgeons. 

Fig.  5.  Transverse  section  of  the  shaft  of  a  foetal  long  bone,  displaying 
the  fact  that  in  fetal  bones  there  are  no  Haversian  canals, 
such  entirely  consisting* of  medullary  cells.     20  diameters. 

Fig.  6.  Transverse  section  of  the  rib  of  an  adult,  magnified  130  diam- 
eters, passing  obliquely  through  the  junction  of  the  cartilage 
with  the  bone :  in  the  upper  part  of  the  figure  the  cancelli 
are  seen,  including  the  terminal  portions  of  the  lowest  tier 
of  cartilage  cells. 


PlcuteZZXV. 


'■  .'.>S'^. 


82  EXPLANATION     OF     THE     PLATES 


PLATE    XXXVI, 


STRUCTURE   OF   TEETH. 


Fig.  I.  Vertical  section  of  incisor  tooth,  magnified  with  a  lens  only, 
and  showing  the  three  constituents  of  which  every  human 
tooth  is  composed,  viz:  superiorly,  the  enamel;  inferiorly, 
the  cementum ;  and  in  the  centre,  the  dentine,  traversed  in 
the  midst  by  the  medullary  cavity. 

Fig.  2.  Tubes  of  the  dentine,  showing  their  ordinary  mode  of  termi- 
nation in  connexion  with  the  cementum,  magnified  670 
diameters. 

Fig.  3.  A  not  unfrequent  condition  of  the  tubes  of  the  dentine,  show- 
ing their  repeated  division,  and  their  connexion  with  bone 
cells  near  their  termination.     670  diameters. 

Fig.  4.  Tubes  of  the  dentine  near  their  commencement  from  the  pulp 
cavity  seen  lengthways :  one  of  the  tubes  may  be  observed 
to  divide  in  a  diachotomous  manner.     670  diameters. 
Oblique  section  of  tubes  of  the  dentine.     670  diameters. 
Transverse  section  of  ditto.     670  diameters. 
Displays  the  breaking  up  of  the  tubes  of  the  dentine  into  bone 
cells :  this  occurs  principally  near  the  terminations  of  those 
tubes  which  pass  towards  the  cementum,  and  not  of  those 
which  run  towards  the  enamel :  this  condition  does  not  pre- 
sent itself  in  every  tooth.     670  diameters. 

Fig.  8.  Tubes  of  the  dentine,  midway  between  their  origin  and  their 
termination,  dilated  into  bone  cells.     670  diameters.     This 
figure  is  taken  from  a  specimen  kindly  lent  me  by  Mr.  Tomes. 
11 


Fig. 

5. 

Fig. 

6. 

Fig. 

7. 

Plate,  XXXVI. 


i    I 

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g    s    ■     : 

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S.  Miller,  del. 


E.C.ICello^.lith 


84  EXPLANATION  OF  THE  PLATES. 


PLATE    XXXVII. 


STRUCTURE    OF    TEETH. 


Fig.  1.  Section  of  cementum,  magnified  670  diameters;  internally, 
but  really  near  the  outer  margin  of  the  cementum,  some 
imperfectly  developed  bone  cells  may  be  observed,  each 
surrounded  by  a  clear  space,  having  some  resemblance  to  a 
cell  wall;  externally,  and  bordering  upon  the  dentine,  a 
closely  aggregated  layer  of  still  more  imperfectly  formed 
bone  cells  are  seen. 

Fig.  2.  Section  of  same  traversed  by  tubes,  continuations  of  those  of 
the  dentine.     670  diameters. 

Fig.  3.  Section  of  cementum,  showing  a  number  of  small  angular 
cells,  and  which  may  frequently  be  observed  in  that  portion 
of  the  cementum  which  lies  near  to  the  dentine.  670 
diameters. 

Fig.  4.  Oblique  section  of  healthy  dentine,  over  the  surface  of  which 
a  fungus  has  developed  itself.  It  is  no  uncommon  circum- 
stance to  meet  with  sections  thus  completely  invested  with 
a  similar  fungus;  I  have  seen  several  such.     670  diameters. 

Fig.  5.  Oblique  section  of  dentine,  in  which  numerous  bright  globules, 
having  a  resemblance  to  oil  globules,  are  observed  to  be 
present.     350  diameters. 

Fig.  6.  Section  of  secondary  dentine,  and  which  also  contains  Haver- 
sian canals.  This  drawing  was  made  from  a  preparation 
belonging  to  Mr.  Tomes.     350  diameters. 

Fig.  7.  Transverse  section  of  bicuspid  tooth,  showing  the  presence 
of  an  Haversian  canal  in  the  cementum,  magnified  with  a 
lens  only.  This  drawing  has  also  been  made  from  an  inter- 
esting preparation,  the  property  of  Mr  Tomes. 


2       Plate.  XXXV/7. 


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H.Millar,  del. 


E.C.ICelloiJjS.lith. 


EXPLANATION     OF     THE     PLATES, 


PLATE     XXXIX. 

STRUCTURE   OF   TENDONS,    TEETH,    AND   FIBROUS   TISSUE.     • 

Fig.  L  Longitudinal  section  of  a  tendon,  showing  the  presence  in  it 

of  nucleated  fibres  of  elastic  tissue ;  these  are  best  seen  after 

the  application  of  acetic  acid,  but  may  be  clearly  recognised 

without  the  employment  of  that  reagent.     670  diameters. 
Fig.  2,  Transverse  section  of  same,  from  which  it  becomes  evident 

that  the  fibres  are  branched.     670  diameters. 
Fig.  3.  Vertical  section  of  enamel,  magnified  220  diameters.     The 

enamel  cells  thus  lowly  magnified  give  the  section  a  fibrous 

appearance. 
Fig.  4.  A  portion  of  enamel,  magnified  670  diameters,  and  showing 

the  enamel  cells  still  more  clearly. 
Fig.  5.  Transverse  section  of  enamel,  showing  the  hexagonal  form  of 

the  enamel  cells.     670  diameters. 
Fig.  6.  Inelastic  fibrous  tissue,  magnified  670  diameters. 
Fig.  7.  Mixed  fibrous  tissue:  the  threads  of  the  elastic  fibrous  tissue 

may  be  recognised  by  their  tortuous  course  and  more  defined 

outline.     670  diameters. 


FL(Lt&  IXXIX. 


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H  Miller,  del. 


E.C.Kello6d.lith. 


88  EXPLANATION      OF     THE     PLATE 


PLATE     XL. 

STRUCTURE   OF   FIBROUS   TISSUE. 

Fig.  1.  Example  of  elastic  fibrous  tissue  in  its  ordinary  form,  taken 
from  the  crico-thyroid  membrane,  and  magnified  670 
diameters. 

Fig.  2.  Form  of  elastic  tissue,  constituting  the  elastic  coat  of  many 
blood-vessels  of  medium  calibre.     670  diameters. 

Fig.  3.  This  figure  illustrates  various  stages  in  the  development  of 
blood-vessels.  At  first,  a  transparent  and  tubular  membrane 
is  surrounded  by  a  single  coil  of  elastic  tissue;  subsequently, 
other  coils  and  filaments  appear,  the  filaments  principally  take 
a  longitudinal  direction  on  the  tubular  membrane,  but  some 
also  pass  circularly  around  this ;  these  threads  are  nucleated, 
and  belong  to  the  second  form  of  elastic  tissue,  and  which 
is  elsewhere  encountered  in  the  human  organization,  as  in 
tendons,  the  dartos,  &c.  350  diameters.  In  h  the  threads 
are  shown  separately. 

Fig.  4.  A  peculiar  areolar  form  of  mixed  fibrous  tissue,  magnified 
130  diameters,  and  principally  encountered  in  the  great 
omentum. 

Fig.  5.  Blood-vessels  from  the  pia  mater.  All  the  smaller  vessels  pre- 
sent a  similar  structure,  their  coats  being  formed  of  nucleated 
filaments  of  elastic  tissue.     350  diameters. 


I. Miller,. lei. 


E'.C.Kellogs.litli. 


90  EXPLANATION     OF     THE     PLATES. 


PLATE     XL  I. 


STRUCTURE   OF   MUSCLE. 


Fig.  1.  A  portion  of  the  surface  of  a  striped  muscle,  magnified  about 
60  diameters,  showing  the  distribution  of  the  blood-vessels 
and  fat  globules. 

Fig.  2.  A  fragment  of  unstriped  muscle;  the  fibres,  with  their  nuclei, 
in  one-half  of  the  figure  are  less  distinct  than  in  the  other, 
the  filaments  in  the  second  half  having  been  submitted  to 
the  action  of  acetic  acid.     670  diameters. 

Fig.  3.  Muscular  fibrillee  of  the  heart;  previous  to  the  action  of  acetic 
acid,  they  are  observed  to  be  transversely  striped;  this 
reagent,  however,  obliterates  the  stripes,  and  reduces  the 
fibrillae  to  the  same  condition  as  those  of  unstriped  muscle. 
670  diameters. 

Fig.  4.  A  fragment  of  the  muscle  of  the  frog,  showing  the  distribution 
of  the  capillary  vessels  and  nerves ;  the  tubules  of  these  last 
are  observed  to  terminate  in  ganglion-like  bodies  situated 
between  the  muscular  fibrillee.     350  diameters. 
12 


Plate  XII. 


H.Mffler.ael 


92  EXPLANATION     OF     THE     PLATE 


PLATE    XLII. 

STRUCTURE   OF   MUSCLE. 

Fig.  1.  Muscular  fibres  and  fibrillae  of  a  voluntary  muscle;  in  one  of 
the  fibres  the  fibrillae  have  given  way,  thus  allowing  the  sar- 
colemma  to  become  apparent.  This  figure,  as  well  as  most 
of  the  remaining  figures  on  this  plate,  are  all  magnified 
about  350  diameters. 

Fig.  2.  Voluntary  muscular  fibres  acted  upon  by  acetic  acid,  which 
brings  clearly  into  view  a  number  of  granular  nuclei;  these 
nuclei  are  contained  in  the  fibrillae,  many  of  which  are 
unstriped,  and  two  of  which  are  represented  in  the  figure 
separately.     350  diameters. 

Fig.  3.  This  figure  represents  particulars  in  reference  to  muscular 
contraction;  in  a,  a  fibre  is  shown  which  has  been  placed 
upon  the  stretch,  the  striae  in  it  are  observed  to  be  somewhat 
distant,  b  represents  the  same  fibre  in  a  state  of  normal 
and  ordinary  contraction ;  the  diameter  of  the  fibre  is  seen 
to  be  much  greater  and  the  striae  closer,  a  4,  the  torn  extrem- 
ity of  a  fibre  immersed  in  water  prior  to  the  total  extinction 
of  its  irritability,  and  which  is  observed  to  be  very  greatly 
contracted ;  the  difference  of  distance  between  the  striae  in 
the  contracted  and  uncontracted  portions  of  the  fibre  is  very 
remarkable.  C  d,  a  fibre  which  still  retained  its  irritability 
immersed  in  water;  this  has  caused  the  fibre  to  curl  up,  to 
become  irregular  and  undulated;  the  transverse  striae  have 
disappeared,  the  longitudinal  markings  at  the  same  time 
being  more  apparent;  in  e  the  extremity  only  of  the  fibre 
has  been  immersed  in  water. 

Fig.  4.  Shows  the  great  variety  in  the  size  of  the  fibres  of  a  muscle, 
the  form  of  the  extremities  of  the  fibres,  and  the  mode  of 
union  between  these  and  the  tendon.     130  diameters. 

Fig.  5.  Transverse  section  of  muscular  fibres  and  intervening  capilla- 
ries.    350  diameters. 


FlaloXLII. 


H.Mffler.ael. 


~£i  C. Epilogs. lith.. 


EXPLANATION     OF     THE     PLATES.  93 


PLATE    XLIII. 

Fig.  1.  A  portion  of  a  voluntary  muscle  of  a  foetus  about  three  months 
old,  magnified  670  diameters,  presenting  numerous  nuclei, 
some  of  which  are  imbedded  in  the  fibres,  and  others  lie 
between  them.  At  this  early  period  the  fibres  are  formed  of 
but  few  fibrillee.  The  small  size  of  these  fibres  in  comparison 
with  those  of  the  adult,  and  which  are  represented  in  fig.  6, 
is  worthy  of  note.     670  diameters. 

Fig.  2.  Illustrates  the  development  of  the  inelastic  form  of  fibrous 
tissue  from  nucleated  and  granular  cells.  This  figure  was 
also  taken  from  a  foetus  at  about  the  third  month.  670 
diameters. 

Fig.  3.  A  portion  of  dartos,  magnified  350  diameters,  showing  the 
different  structures  which  enter  into  its  composition,  viz: 
the  blood-vessels,  the  bands  of  elastic  fibrous  tissue,  and 
lastly,  the  bundles  of  inelastic  fibrous  tissue. 

Fig.  4.  A  transverse  section  of  a  portion  of  one  of  the  corpora  cavern- 
osa penis,  showing  the  apertures  of  the  vessels  or  cells  of 
which  they  are  principally  composed,  as  well  as  the  walls  of 
those  cells  which  are  formed,  not  of  nucleated  elastic  tissue, 
but  of  branched  and  reticular  elastic  filaments.  This  figure 
is  magnified  only  a  few  diameters. 

Fig.  5.  Muscular  fibres  of  voluntary  muscle,  disposed  in  a  zigzag 
manner;  this  disposition  was  formerly  considered  to  be  nor- 
mal, and  to  be  that  assumed  by  the  fibres  of  every  muscle 
in  a  state  of  contraction,  a  view  which  is  certainly  errone- 
ous ;  it  is  encountered  in  a  greater  or  less  degree  in  all  fried 
and  roasted  meats.     350  diameters. 

Fig.  6.  Striped  muscular  fibres,  magnified  670  diameters.  It  will  be 
seen  from  the  figure,  that  the  surface  of  each  fibre  is  raised 


94  EXPLANATION     OF     THE     PLATES. 

into  ridges  with  a  narrow  space  intervening  between  each 
ridge,  and  further,  that  the  ridges  are  marked  out  into  quad- 
rangular spaces,  each  of  which  corresponds  with  a  division 
of  the  fibrillae  themselves.  Now,  this  form  of  the  surface  of 
a  striped  fibre  is  especially  interesting,  from  the  fact  of  its 
enabling  us  to  afford  a  satisfactory  explanation  of  the  nature 
of  the  striae  themselves.  The  most  recent  explanation  given 
of  the  formation  of  the  striae  of  the  voluntary  muscular  fibre, 
and  which  has  been  generally  adopted,  is,  that  it  depends 
upon  the  circumstance  that  the  lines  on  the  fibrillae  are 
placed  so  as  exactly  to  correspond  with  each  other,  and  that 
thus  a  number  of  smaller  lines  concur  to  form  a  larger  one, 
the  stria  of  the  entire  fibre.  Such  an  exact  arrangement  of 
the  lines  on  the  fibrillae  there  is  little  doubt  does  really  exist, 
but  it  is  yet  insufficient  to  explain  all  the  characters  pre- 
sented by  the  muscular  striae.  Thus,  although  the  striae  are 
usually  strongly  marked  and  broad,  yet  they  have  no  certain 
characteristics,  either  as  to  position  or  appearance.  In  what 
way  then  is  the  muscular  stria  produced?  A  careful  exam- 
ination of  a  recent  muscular  fibre,  with  an  object-glass  of 
the  one-eighth  of  an  inch  focus,  will  satisfy  the  observer 
that  the  muscular  stria  is  not  a  thing  of  shape  and  substance 
itself,  but  a  mere  shadow,  caused  by  the  ridges  into  which 
the  surface  of  the  fibre  is  raised,  and  which  sometimes  falls 
on  one  side  the  ridge,  sometimes  on  the  other,  and  frequently 
in  the  groove  which  runs  between  the  ridges,  according  to 
the  direction  of  the  light,  and  the  focus  in  which  the  object 
is  viewed.  Of  the  correctness  of  this  explanation  it  does 
not  appear  to  me  that  there  can  be  a  shadow  of  doubt. 
See  Appendix  to  vol.  i.,  page  547. 


Flat&  Mill. 


~^-^r~—-:f,.   _    'i 


■N 


m 

[ / '   Mm 


H.Miller,del. 


E.C. Kellogg,  Jith. 


90  EXPLANATION     OF     THE     PLATES. 


PLATE     X  L  I V. 


STRUCTURE   OP    NERVES. 


Fig.  1.  Tubes  of  a  motor  nerve.  The  space  between  the  two  lines 
on  each  margin  indicates  the  thickness  of  the  white  sub- 
stance of  Schwann.  The  waved  tube  represents  the 
appearance  presented  by  the  nervous  tubules,  when  sepa- 
rated from  each  other  in  water.     670  diameters. 

Fig.  2.  The  same  in  spirit,  showing  the  nucleated  threads  of  which 
the  neurilemma  is  made  up.     670  diameters. 

Fig.  3.  The  same  in  acetic  acid,  which  breaks  up  the  semi-fluid  con- 
tents of  the  tubes  into  globules  resembling  those  of  oil.  670 
diameters. 

Fig.  4.  Portions  of  Casserian  ganglia,  magnified  350  diameters.  In 
one  of  the  figures,  the  ganglion  corpuscles  are  naked ;  in  the 
otrnr,  they  are  invested  with  a  nucleated  capsule. 

Fig.  5.  Nerve  tubes  of  the  white  substance  of  the  cerebellum,  mixed 
up  with  the  clear  cells  described  in  the  text  as  forming  a 
considerable  portion  of  the  white  substance  of  the  cerebrum, 
cerebellum,  spinal  marrow,  and  nerves  of  special  sense.  670 
diameters. 

Fig.  6.  Nerve  tubes  of  the  white  substance  of  one  of  the  hemispheres 
of  the  cerebrum,  mixed  up  with  the  peculiar  cells  already 
referred  to.     670  diameters. 

Fig.  7.  Tubes  of  the  cerebrum  in  a  varicose  condition.    670  diameters. 


TUte  XLJV. 


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H.Miller.del. 


E.C.Kello^g.lith. 


"98  EXPLANATION     OF     THE     PLATES. 


PLATE    XLV. 

The  majority  of  the  figures  in  the  following  Plates  were  made  with  the  assistance 
of  the  Camera  Lucida,  and  the  same  instrument  will  be  employed  in  the  delineation 
of  all  future  figures  wherever  practicable. 

Fig.  1.  Filaments  of  the  great  sympathetic,  magnified  670  diameters. 

Fig.  2.  Cells  of  the  gray  matter  of  the  cerebellum,  outer  stratum.  670 
diameters. 

Fig.  3.  Ditto,  inner  stratum.     670  diameters. 

Fig.  4.  Caudate  ganglionary  cells  from  the  gray  matter  of  the  spinal 
cord,  medulla  oblongata,  and  cerebellum ;  magnified  350 
diameters.  Those  from  the  first  locality  are  distinguished 
from  the  rest  by  their  larger  size;  those  from  the  second 
situation  by  their  smallness  and  elongated  form,  and  the  cells 
from  the  cerebellum  by  their  intermediate  size  and  flask 
shape. 

Fig.  5.  Caudate  ganglionary  cells  from  the  locus  niger  of  the  crua 
cerebelli.     350  diameters. 

Fig.  6.  Minute  caudate  cells  from  the  hippocampus  major.  350 
diameters. 

Fig.  7.  Ditto,  from  the  locus  niger  of  crus  cerebri.     350  diameters. 

13 


Flate  XLV. 


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E.C.Xellogtf.litL 


100  EXPLANATION     OF     THE     PLATES, 


PLATE    XLVI. 

Fig.  I.  Pacinian  corpuscles  attached  to  the  cutaneous  nerves  of  the 

palm  of  the  hand.     Natural  size.     After  Todd  and  Bowman. 
Fig.  2.  Pacinian  corpuscles,  magnified  60  diameters. 
Fig.  3.  A  single  Pacinian  body,  more   highly  magnified,  viz:    100 

diameters. 
Fig.  4.  An  anomalous  Pacinian  body  from  the  mesentery  of  the  cat. 

After  Todd  and  Bowman. 
Fig.  5.  Two  other  anomalous  Pacinian  bodies  from  the  same  animal. 

The  latter,  reduced  from  Henle  and  Kolliker. 
Fig.  6.  Ganglionary  cells  from  the  corpus  dentatum  of  the  cerebellum. 

350  diameters. 


FLaizXLVI. 


E.C.Kello^lith 


102  EXPLANATION     OF     THE     PLATES. 


PLATE    XLVII. 

Fig.  1.  The  pleural  surface  of  a  portion  of  lung,  magnified  30  diam- 
eters. This  figure  conveys  an  accurate  idea  of  the  form 
and  great  abundance  of  the  air  cells. 

Fig.  2.  Pleural  surface  of  a  section  of  lung,  showing  the  distribution 
of  the  vessels  of  the  first  of  the  three  orders  of  sizes  mentioned 
in  the  text.     30  diameters. 

Fig.  3.  Ditto  of  lung,  magnified  100  diameters.  The  vessels  in  this 
are  not  injected,  but  are  represented  as  they  appeared  in  a 
section  which  had  become  slightly  dried. 


Plate  XLVII. 


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K.C  Kellogg,  lith. 


104  EXPLANATION      OF     THE     PLATES. 


PLATE    XLVIII. 

Fig.  1.  A  section  of  lung  from  beneath  the  pleural  surface,  magni- 
fied 100  diameters,  injected  with  tallow. 

Fig.  2.  Casts  or  models  of  the  air  cells,  magnified  350  diameters, 
representing  the  variety  in  size  and  form  of  these  cells,  as 
well  as  the  shape  and  number  of  the  openings  of  com- 
munication. 

Fig.  3.  Deep  section  of  lung,  injected  with  size :  the  majority  of  the 
cells  are  observed  to  be  filled  with  the  casts  tipped  with 
colouring  matter :  other  cells  may  also  be  seen  without  casts : 
these  have  evidently  been  cut  across,  exposing  to  view  the 
ciliated  epithelium  which  lines  them.     100  diameters. 


Plate  XLVJir. 


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E.CKellojg.lith 


106  EXPLANATION     OF     THE     PLATES. 


PLATE    XLIX. 

Fig.  1.  A  portion  of  the  pleural  surface  of  the  human  lung,  with  the 
vessels  of  the  second  order  injected.  Magnified  100 
diameters. 

Fig.  2.  A  section  of  the  human  lung,  showing  the  natural  appearance 
and  form  of  the  air  cells  as  seen  without  injection,  also 
exhibiting  numerous  particles  of  the  conoidal  ciliated  epithe- 
lium which  lines  them.     100  diameters. 

Fig.  3.  Capillaries  of  the  human  lung.     Magnified  100  diameters. 
The  drawing  was  made  from  a  very  beautiful  preparation 
injected  by  Mr.  Quekett. 
14 


Rate  XLIX 


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E.CKe]lo°6.1itii. 


108  EXPLANATION     OF     THE     PLATES. 


PLATE   L  . 

Fig.  1.  Follicles  of  the  stomach,  as  they  appear  when  lined  with 
conoidal  epithelium.     100  diameters. 

Fig.  2.  Ditto  of  large  intestine  in  a  similar  condition.     100  diameters. 

Fig.  3.  Cross-section  of  stomach  tubes,  magnified  100  diameters.  The 
tubes  are  parcelled  out  into  sets  only  when  about  to  pierce 
the  follicles  into  which  they  open;  and  it  is  rare  to  get  a 
good  view  of  them  thus  disposed  in  bundles,  each  of  which 
corresponds  to  the  base  of  a  follicle. 

Fig.  4.  Longitudinal  view  of  stomach  tubes,  magnified  220  diameters, 
showing  the  spheroidal  or  glandular  epithelium  with  which 
they  are  lined,  as  well  as  the  dilated  extremities  in  which 
they  terminate. 

Fig.  5.  Ditto,  magnified  100  diameters. 

Fig.  6.  Follicles  of  the  large  intestine  without  epithelium,  and  cut  off, 
so  as  to  admit  the  passage  of  light  through  them :  when  not 
thus  shortened,  their  apertures  appear  dark,  in  consequence 
of  the  non-transmission  of  the  light.     60  diameters. 

Fig.  7.  Terminations  of  the  follicles  of  the  large  intestine.  Magnified 
60  diameters. 


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110  EXPLANATION     OF     THE     PLATES, 


PLATE   LI. 

Fig.  1.  Blood-vessels  of  the  follicles  of  the  appendix  vermiformis 
injected.     Magnified  100  diameters. 

Fig.  2.  Blood-vessels  of  the  follicles  of  the  stomach  of  a  cat,  beautifully 
injected.  The  drawing  was  made  from  a  preparation  of 
Dr.  Handfield  Jones.     100  diameters. 

Fig.  3.  Villi  of  the  upper  part  of  the  small  intestine,  magnified  60 
diameters.     Drawing  made  from  a  preparation  of  Dr.  Jones. 

Fig.  4.  Ditto,  from  the  lower  portion  of  the  same.     60  diameters. 

Fig.  5.  Ditto  of  the  foal,  injected  white  and  red,  the  arteries  being 
red  and  the  veins  white.  Magnified  60  diameters.  Draw- 
ing made  from  a  preparation  presented  by  Professor  Hyrtle, 
of  Prague,  to  the  London  Microscopical  Society. 

Fig.  6.  Solitary  glands  of  the  large  intestine  in  a  case  of  cholera  in  a 
child.     Magnified  with  a  lens  only. 


Plate  II. 


H  Miller,  del. 


E.CKeUogg.hth" 


112  EXPLANATION     OF     THE     PLATES, 


PLATE    L  II. 

Fig.  1.  Villi,  showing  the  layer  of  epithelial  cells  with  which  they  are 
generally  covered,  especially  during  the  intervals  of  digestion. 
Magnified  100  diameters. 

Fig.  2.  Ditto,  uncovered  by  the  layer  of  epithelium  figured  in  the 
previous  drawing,  and  showing  the  lacteals,  as  well  as  the 
granular  cells,  which  the  villi  always  contain,  whether  in  an 
active  or  passive  condition.     100  diameters. 

Fig.  3.  Peyer's  glands  in  the  cat.  Magnified  20  diameters.  The 
vessels  in  the  villi,  between  the  glands,  are  injected;  but 
those  of  the  glands  themselves  are  not  so,  and  this  accounts 
for  their  being  uncoloured. 

Fig.  4.  Vertical  section  of  the  mucous  membrane  of  the  ileum  of  the 
cat,  showing  the  flask-like  form  of  Peyer's  glands.  No 
essential  difference  exists  between  these  glands,  as  they 
occur  in  most  of  the  Mammalia,  and  in  the  human  subject. 
This  and  the  previous  drawing  were  prepared  from  two  very 
perfect  preparations,  kindly  lent  me  by  Mr.  Quekett.  20 
diameters. 

Fig.  5.  Follicles  of  Lieburkiihn  in  the  duodenum.  Magnified  60 
diameters. 

Fig.  6.  Solitary  glands  of  the  small  intestines  uninjected,  of  their 
natural  size,  and  as  they  occurred  in  a  case  of  muco-enterite 


Plate  LIT. 


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114  EXPLANATION     OF     THE     PLATES, 


PLATE    LI'I-I. 

Fig.  1.  A  sebaceous  gland  from  the  caruncula  lachrymalis  in  the 
human  subject;  the  follicles,  on  closer  examination,  I  find 
to  be  provided  with  minute  hairs,  similar  to  those  which  are 
present  in  the  sheep  and  some  other  animals. 

Fig.  2.  An  entire  Meibomian  gland.     27  diameters. 

Fig.  3.  Sebaceous  glands  in  connexion  with  a  hair  of  the  scalp. 
These  glands  are  easily  procured  still  attached  to  the  hair 
follicle,  provided  the  portion  of  integument  from  which  they 
are  to  be  obtained  be  permitted  to  undergo  a  slight  degree 
of  decomposition.     33  diameters. 

Fig.  4.  Illustrations  of  mucous  glands.  The  centre  figure  represents 
a  portion  of  a  gland  and  several  of  the  apertures  by  which 
the  follicles  in  the  larger  mucous  glands  communicate  with 
each  other.     45  diameters. 

15 


Plate  LIII. 


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E.C.Kellotfg.lilk 


116  EXPLANATION     OF     THE     PLATES 


PLATE    LIV. 

Fig.  1.  A  portion  of  the  parotid  gland  of  an  embryo  of  the  sheep,  four 
inches  long,  showing  it  in  the  very  earliest  condition  of  its 
development  in  which  it  can  be  traced ;  the  follicles,  although 
arranged  in  clusters,  are  yet  separate  and  independent  of 
each  other.     After  Muller.     Magnified  8  diameters. 

Fig.  2.  Shows  a  further  development  of  the  parotid  gland  in  the 
human  subject ;  in  this  figure  the  follicles  are  closely  aggre- 
gated in  clusters,  each  cluster  representing  a  miniature 
lobule.     40  diameters. 

Fig.  3.  A  portion  of  mammary  gland  filled  with  milk  globules.  90 
diameters. 

Fig.  4.  A  section  of  liver,  showing  the  form  of  the  lobules  and  the 
arrangement  of  the  secreting  cells.  The  light  spaces  in  the 
centre  of  the  lobules  indicate  the  position  of  the  central 
hepatic  veins.     35  diameters. 

Fig.  5.  A  portion  of  mammary  gland,  but  slightly  magnified. 

Fig.  6.  Ditto,  more  highly  magnified,  showing  clearly  both  its  small 
granular  secreting  cells  and  the  milk  globules.  198  diam- 
eters. 


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118  EXPLANATION     OF     THE     PLATES 


PLATE   LV. 

Fig.  1.  A  portion  of  the  surface  of  the  liver,  showing  the  lobules  and 
the  intra-lobular  hepatic  veins.  The  injection  has  filled 
only  the  larger  vessels,  and  has  scarcely  penetrated  to  the 
capillaries.     15  diameters. 

Fig.  2.  Section  of  liver,  in  which  the  hepatic  venous  system  has  been 
very  completely  injected,  and  the  portal  (in  yellow)  only 
slightly  so.  The  communication  between  the  vessels  of 
different  lobules  is  also  well  shown.  Drawing  made  from  a 
preparation  of  Dr.  Handheld  Jones.     20  diameters. 

Fig.  3.  Would  appear  to  be  a  portion  of  the  portal  system ;  the  injec- 
tion was  thrown  in  from  the  ductus  communis  choledochus. 
.  When  introduced  in  this  way,  this  system  always  becomes 
irregularly  filled;  and  the  lobules  are  not  circumscribed  as 
when  the  injection  enters  directly  by  the  portal  vein.  20 
diameters. 

Fig.  4.  A  section  of  liver,  in  which  the  inter-lobular  portal  vessels 
are  shown.  The  injection  in  this  case  also  fills  only  the 
principal  vessels,  and  has  not  extended  to  the  capillaries.  24 
diameters. 


E.C.Keilooo.lith. 


120  EXPLANATION     OF     THE     PLATES. 


PLATE    LVI. 

Fig.  1.  A  portion  of  the  surface  of  the  liver,  in  which  the  portal  cap- 
illary system  has  been  injected.     20  diameters. 

Fig.  2.  Section  of  liver,  in  which  both  the  portal  vein  and  the  hepatic 
artery  have  been  injected,  the  red  vessels  indicating  branches 
of  the  hepatic  artery.  The  drawing  was  made  from  a  very 
perfect  injection,  kindly  lent  me  for  the  purpose  by  Mr. 
Quekett.     18  diameters. 

Fig.  3.  A  portion  of  the  surface  of  the  liver,  in  which  both  the  hepatic 
and  portal  venous  systems  are  well  shown,  each  being  dis- 
tinct. Drawing  made  from  a  preparation  of  Dr.  Handfield 
Jones.     20  diameters. 

Fig.  4.  A  section  of  liver,  in  which  both  the  portal  and  hepatic 
venous  systems  have  been  completely  injected  from  the 
portal  vein.     20  diameters. 


PlcLt&  LVI. 


122  EXPLANATION     OF     THE     PLATES. 


PLATE    LVII. 

Fig.  1.  A  terminal  biliary  duct,  copied  from  a  drawing  of  Dr.  H. 
Jones.     378  diameters. 

Fig.  2.  Secreting  cells  of  the  liver.  The  group  lettered  a  represents 
the  cells  in  the  usual  condition  in  which  they  are  met,  when 
submitted  to  observation:  in  b,  the  cells  are  gorged  with  bile, 
while  in  c,  they  contain  numerous  fat  or  oil  globules.  378 
diameters. 

Fig.  3.  Concretions  or  calculi  from  the  prostate  gland.    45  diameters. 

Fig.  4.  a  represents  an  hitherto  undescribed  form  of  tubular  gland  oc- 
curring in  the  region  of  the  human  axilla  in  close  connexion 
with  the  large  sudoriferous  glands  which  are  there  met  with. 
54  diameters.  It  differs  from  these  last,  however,  in  several 
particulars,  but  principally  in  the  smaller  calibre  of  the  tubes, 
and  the  presence  (clearly  shown  by  the  action  of  acetic 
acid)  of  innumerable  nuclei  in  the  walls  of  the  tubes,  and 
of  which  these  would  appear  to  be  principally  constituted. 
In  b  and  c,  the  differences  in  the  size  and  structure  of  the 
tubes  in  the  two  glands  are  shown,     b  and  c  198  diameters. 

Fig.  5.  Ceruminous  glands.  I  cannot  detect  the  slightest  difference 
between  these  glands  and  ordinary  sudoriferous  glands,  with 
which,  it  would  appear,  they  must  be  considered  to  be  iden- 
tical.    45  diameters. 

16 


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124  EXPLANATION      OF     THE     PLATES. 


PLATE    LVIII. 

Fig.  1.  Tubes  of  the  kidney,  showing  their  general  character,  and  but 
slightly  magnified.     99  diameters. 

Fig.  2.  Cross-section  of  the  elastic  frame-work  in  which  both  the 
secreting  tubes  and  the  Malpighian  bodies  are  enclosed.  99 
diameters. 

Fig.  3.  Cross-section  of  both  the  elastic  frame-work  and  the  secreting 
tubes  themselves.     99  diameters. 

Fig.  4.  Oblique  section  of  the  veins  contained  in  the  tubular  part  of 
the  kidney,  showing  their  arrangement  in  sets.     33  diameters. 

Fig.  5.  The  same  vessels  seen  lengthways.     33  diameters. 

Fig.  6.  Secreting  tubes  of  the  kidney,  in  different  conditions:  in  one, 
the  cells  are  seen  to  form  a  regular  pavement  epithelium ;  in 
a  second,  the  central  canal,  along  which  the  urine,  secreted 
by  the  Malpighian  bodies  and  cells  of  the  tubes,  flows,  is 
shown;  in  a  third,  the  cells  are  irregularly  disposed,  and  this 
is  generally  found  to  be  the  case  in  the  tubes  of  the  central 
part  of  the  kidney,  and  when  the  kidney  is  not  perfectly 
fresh;  in  a  fourth,  there  are  no  secreting  cells,  and  the 
structureless  basement  membrane  of  the  tubes  alone  remains. 
378  diameters. 


Plate,  LVIII. 


jE  .C.Kelloag.lith. 


126  EXPLANATION     OF     THE     PLATES, 


PLATE    LIX. 

Fig.  1.  Longitudinal  section  of  kidney,  showing  the  corpora  Mal- 
pighiana.     Magnified  40  diameters. 

Fig.  2.  Uriniferous  tubes  of  a  bird  {Gallus  indicus),  showing  their 
pinnatifid  arrangement.  Drawing  made  from  a  preparation 
of  Professor  Hyrtl,  in  the  possesion  of  the  Microscopical 
Society  of  London.     40  diameters. 

Fig.  3.  Corpora  Malpighiana  of  the  horse.  Drawing  made  from  an 
injected  preparation  by  Professor  Hyrtl.     40  diameters. 

Fig.  4.  Vessels  of  the  surface  of  the  kidney.  The  capillaries  are  situ- 
ated in  the  interstices  between  the  tubes.     90  diameters. 

Fig.  5.  A  transverse  section  of  the  kidney,  more  highly  magnified, 
showing  the  convoluted  vessels  of  the  corpora  Malpighiana, 
as  well  as  the  capillaries  which  encircle  the  uriniferous  tubes. 
67  diameters. 


lictte  LIX 


E.C-Kellogi.liti. 


128  EXPLANATION     OF     THE     PLATES, 


PLATE    LX. 

Fig.  1.  Tubes  of  the  testis,  slightly  magnified,  showing  their  general 
appearance  and  arrangement. 

Fig.  2.  Uninjected  corpora  Malpighiana.  a  is  enveloped  in  its  own 
proper  capsule,  while  in  b  this  has  been  removed.  Magnified 
100  diameters.  Additional  observations  have  convinced  me 
that  these  complicated  bodies  are  invested,  in  addition  to  the 
thick  elastic  covering  spoken  of  in  the  text,  with  an  inner 
and  much  thinner  membrane;  and  that  it  is  this  which  is  to 
be  regarded  as  the  proper  Malpighian  capsule.  This  cover- 
ing, I  conceive,  is  conveyed  to  each  Malpighian  body  by  the 
afferent  artery,  from  which  it  is  reflected  over  the  Malpighian 
dilatation  and  plexus  of  vessels ;  and  it  may  often  be  seen  as 
a  distinct  structure,  partially  separated  from  the  other  con- 
stituents of  a  Malpighian  body.  The  frame-work  of  elastic 
tissue,  which  invests  on  every  side  the  tubes  and  Malpighian 
bodies,  is  every  where  continuous  by  its  outer  surface,  that  of 
one  tube  with  that  of  the  neighbouring  tubes,  and  that  of  the 
Malpighian  body  is  also  continuous  with  that  of  the  tubes 
which  surround  this  Malpighian  body.  On  the  other  hand, 
the  proper  and  thin  Malpighian  capsule  is  smooth  on  its  outer 
surface,  and  not  connected  by  this  surface  with  any  other 
structure,  save  the  afferent  and  efferent  vessels  along  which 
it  is  continued.  This  general  continuity  of  the  elastic  frame- 
work is  well  shown  in  Plate  luWWl.fig.  2. 

Fig.  3.  A.  a  Malpighian  body,  more  highly  magnified,  displaying 
innumerable  small  oval  and  granular  cells.  The  majority 
of  these,  I  am  now  disposed  to  think,  are  contained  in  the 
walls  of  the  vessels  constituting  the  Malpighian  plexus.  The 
figure  b  is  after  Bowman,  and  shows  the  afferent  artery  and 
the  efferent  vein  of  the  Malpighian  tuft;  also,  the  connexion 
of  the  tube  with  the  Malpighian  body  itself;  c,  loose  epithelial 
cells  of  the  tubes.     125  diameters. 

Fig.  4.  Tube  of  the  testis,  more  highly  magnified,  displaying  the 
innumerable  granular  cells  which  fill  the  tube,  as  well  as  the 
structure  of  the  tube  itself.     99  diameters. 


PLat&  IX 


130  EXPLANATION     OF     THE     PLATES. 


PLATE    LXI. 

Fig.  1.  Vessels  of  thyroid  gland.     18  diameters. 

Fig.  2.  Vesicles  of  slightly  enlarged  thyroid,  viewed  with  a  lens  only. 

Fig.  3.  Ditto  of  same,  magnified  40  diameters. 

Fig.  4.  Ditto  of  same,  magnified  67  diameters,  showing  the  fibrous 

structure  of  their  walls,  and   their   cellular   and   nuclear 

contents. 
Fig.  5.  Lobes  and  vesicles  of  thyroid,  magnified  27  diameters,  as  seen 

in  a  gland  in  its  ordinary  condition. 
Fig.  6.  Granular    nuclei    of  vesicles    of   thyroid.      Magnified    378 

diameters. 
Fig.  7.  Two  follicles  of  thymus  gland,  magnified  33  diameters,  show- 
ing the  plexus  of  vessels  which  invests  them. 
Fig.  8.  A  portion  of  the  capsule  of  thymus,  magnified  54  diameters, 

showing  the  ternary  disposition  of  the  vessels. 
Fig.  9.  Granular  nuclei  and  simple  cells  with  fibrous  tissue  of  thymus. 

Magnified  378  diameters. 
Fig.  10.  Compound  cells  of  thymus.     Magnified  378  diameters. 

17 


Plate,  ZZT. 


H  MQIer     el 


E-C.Xelic;;   litb 


132  EXPLANATION  OF  THE  PLATES 


PLATE    LXII. 

Fig.  1.  Granular  nuclei,  blood-vessels,  and  fibro-elastic  tissue  of  spleen. 
Magnified  378  diameters. 

Fig.  2.  Plexus  of  vessels  on  the  surface  of  supra-renal  capsule.  Mag- 
nified 54  diameters. 

Fig.  3.  a.  Tubes  of  supra-renal  capsule.  90  diameters,  b.  Nuclei, 
parent  cells,  and  molecules  of  the  same.     378  diameters. 

Fig.  4.  Vessels  of  the  foetal  portion  of  the  placenta.  Magnified  54 
diameters.     These  are  seen  to  terminate  in  the  villi  in  loops. 

Fig.  5.  Ditto  of  the  supra-renal  capsule,  showing  the  plexus  on  the 
surface  of  the  organ,  the  long  inter- tubular  vessels,  and  the 
central  plexus.     90  diameters. 


Male  LX1I. 


E  C  Kellogg,  lith 


134  EXPLANATION     OF     THE      PLATES. 


PLATE    LXIII. 

Fig.  1.  Epidermis  of  palm  of  hand,  magnified  40  diameters,  showing 
its  disposition  in  ridges,  and  the  apertures  of  the  sudoriferous 
glands. 

Fig.  2.  Epidermis  of  the  back  of  the  hand,  magnified  to  the  same 
extent,  showing  its  furrows,  hairs,  and  apertures  of  sudorif- 
erous ducts. 

Fig.  3.  Papillae  of  palm  of  hand.     Magnified  54  diameters. 

Fig.  4.  Ditto  of  back  of  hand.     Magnified  to  the  same  extent. 

Fig.  5.  Epidermis  of  palm  of  hand,  seen  upon  its  under  surface, 
showing  pits  or  depressions  for  the  reception  of  the  papillae, 
and  the  ducts  of  the  sudoriferous  glands.  Magnified  54 
diameters. 

Fig.  6.  Epidermis  of  the  back  of  hand,  viewed  upon  its  under  surface 
as  a  transparent  object,  and  showing  depressions  for  the 
papillae  and  the  ducts  of  the  sudoriferous  glands.  Magnified 
54  diameters. 

Fig.  7.  Blood-vessels  of  the  papillae  of  the  palm  of  the  hand,  a  single 
loop  corresponds  to  each  papilla.     Magnified  54  diameters. 
8.  Ditto  of  the  back  of  the  hand.     Magnified  54  diameters 


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H.Miller,  del. 


ellooD.iith. 


136  EXPLANATION     OF     THE     PLATES, 


PLATE    LXIV. 

Fig.  1.  Filiform  papillse  of  the  tongue  near  its  centre,  with  epithelial 
appendages  attached.     Magnified  41  diameters. 

Fig.  2.  Ditto  of  same  near  its  apex,  with  epithelial  appendages 
attached;  these  are  seen  to  be  much  shorter  than  in  the 
previous  case.     Magnified  27  diameters. 

Fig.  3.  Ditto  near  the  apex  of  the  tongue,  with  the  epithelium  removed, 
showing  their  cupped  form,  and  the  arrangement  and  number 
of  the  secondary  papillae  around  their  edges.  Magnified  27 
diameters. 

Fig.  4.  Ditto  near  the  centre  of  the  tongue,  in  which  situation  the 
secondary  papillae  are  seen  to  be  much  longer  and  more 
slender  than  in  the  previous  figure,  their  apices  falling 
together,  and  so  obscuring  the  excavation  in  the  centre  of 
each  filiform  papilla.     Magnified  31  diameters. 

Fig.  5.  Filiform  and  fungiform  papillae  of  the  tongue,  deprived  of  their 
epithelium.  The  size,  form,  and  structure  of  the  fungiform 
papillae  are  well  shown,  as  well  as  the  simple  papillae  situated 
in  the  fossa  around  the  base  of  one  of  the  fungiform  papillae. 
Magnified  27  diameters. 

Fig.  6.  Filiform  papillae ;  some  deprived  of  their  epithelial  processes, 
others  still  retaining  them.  In  the  centre  of  the  figure,  two 
filiform  papillae  may  be  seen  occupying  the  position  of  a 
fungiform  papilla,  being  situated  in  a  fossa  studded  with 
simple  papillae.     27  diameters. 

Fig.  7.  The  centre  of  this  figure  represents  a  peculiar  form  of  com- 
pound papillae,  occupying  the  position  of  a  fungiform  papilla, 
but  intermediate  in  structure  between  it  and  a  filiform  papilla. 
27  diameters. 

Fig.  8.  Filiform  papillae,  showing  their  tubular  form,  with  the  epithe- 
lial processes  partially  removed,  and  exhibiting  numerous 
simple  papillae  placed  between  the  compound  ones.  27 
diameters. 


?I.o.te  LXIV. 


Miller,  ild 


eliofie.lith.. 


138  EXPLANATION     OF     THE     PLATES. 


PLATE     LXV. 

Fig.  1.  Mucous  follicles  of  tongue,  from  under  surface,  clothed  with 
their  epithelium.     Magnified  27  diameters. 

Fig.  2.  Ditto,  with  the  epithelium  removed,  viewed  as  transparent 
objects.     Magnified  27  diameters. 

Fig.  3.  Ditto,  with  the  epithelium  removed,  viewed  as  opaque  objects. 
27  diameters. 

Fig.  4.  Filiform  papillae,  still  invested  with  epithelium,  from  the  apex 
of  the  tongue  near  the  tip.  In  this  situation  the  filiform 
processes  are  almost  entirely  absent,  and  the  cupped  form 
of  the  papillae  is  well  seen.     27  diameters. 

Fig.  5.  Mucous  follicles  and  compound  papillae,  still  invested  with 
epithelium,  from  the  side  of  the  tongue.  Magnified  20 
diameters.  These  compound  papillae  approach  the  fungiform 
in  structure. 

Fig.  6.  A  side  view  of  two  simple  papillae  of  the  tongue  partially 
invested  with  epithelium.     45  diameters. 

Fig.  7.  Ditto  of  filiform  papillae,  with  epithelium  and  epithelial  pro- 
cesses still  adherent.     18  diameters. 

Fig.  8.  The  same,  viewed  with  a  lens  only. 

Fig.  9.  Side  view  of  compound  papillae  situated  at  the  sides  of  the 
tongue  posteriorly  to  the  calyciform  papillae:  the  simple 
papillae  of  which  they  are  made  up  are  dilated  at  the  extrem- 
ities.    20  diameters. 

Fig.  10.  Simple  papillae  from  the  under  surface  of  the  tongue.  Mag- 
nified 54  diameters. 

Fig.  11.  Compound  and  simple  papillae  from  the  side  of  the  tongue, 
but  posteriorly  to  the  calyciform  papillae.     Magnified  23 

diameters. 

18 


'    ite  ZXV. 


O    ft 


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H  Millei  Id  uLiiat 


Z  C  Kellood  lith. 


140  EXPLANATION     OF     THE     PLATES. 


PLATE    LXVI. 

Fig.  1.  A  single  calyciform  papilla,  with  the  epithelium  removed, 
showing  the  numerous  secondary  papillae  by  which  it  is 
covered.     16  diameters. 

Fig.  2.  Ditto,  in  a  similar  state,  with  the  vessels  of  the  papillae  injected. 
16  diameters. 

Fig.  3.  Filiform  papillae  near  the  centre  of  the  tongue,  with  the  ves- 
sels injected.     27  diameters. 

Fig.  4.  Ditto  near  the  tip  of  the  tongue,  also  injected.     27  diameters. 

Fig.  5.  Simple  papillae,  injected.     27  diameters. 

Fig.  6.  A  fungiform  papilla,  injected,  surrounded  by  several  filiform 
papilla,  also  injected.     27  diameters. 


PlaU  LXf'l. 


mmMmmm 


milt 


'11  k:^k\ 

\\\V       >^l    W* 


E-(.Mvelloo6.]itlL. 


142  EXPLANATION     OF     THE     PLATES. 


PLATE    LXVII. 

Fig.  1.  Vertical  section  of  cornea,  showing  the  conjunctival  epithe- 
lium, the  cornea  proper,  posterior  elastic  lamina,  and  epithe- 
lium of  the  aqueous  humour.     54  diameters. 

Fig.  2.  A  portion  of  the  vascular  layer  of  the  retina,  injected.  From 
a  preparation  belonging  to  Mr.  Quekett.     60  diameters. 

Fig.  3.  Section  of  sclerotic  and  cornea  at  the  junction  of  the  two 
parts.  In  the  sclerotic,  the  spaces  between  the  fibrous  tissue 
are  seen  to  be  more  or  less  rounded,  while  in  the  cornea 
they  are  elongated  and  tubular.     54  diameters. 

Fig.  4.  Vessels  of  tunica  Ruyschiana,  ciliary  processes,  iris,  and 
membrana  pupillaris,  injected.  From  a  foetal  preparation 
injected  by  Mr.  Hett.     14  diameters. 

Fig.  5.  Nuclei  of  the  granular  layer  of  the  retina.     378  diameters. 

Fig.  6.  Cells  of  the  same.     378  diameters. 

Fig.  7.  Transparent  cells  of  the  vesicular  layer  of  the  retina.  Mag- 
nified 378  diameters. 

Fig.  8.  Caudate  cells  of  the  retina.     378  diameters. 

Fig.  9.  A  portion  of  the  membrana  Jacobi.     378  diameters. 

Fig.  10.  Fibres  of  the  crystalline  lens,  a,  magnified  198  diameters; 
b,  magnified  378  diameters. 

Fig.  11.  Tuberculated  condition  of  the  posterior  elastic  lamina,  as 
seen  near  its  margin.     78  diameters. 

Fig.  12.  Peculiar  markings  on  posterior  elastic  lamina.  Magnified 
78  diameters. 

Fig.  13.  Surface  of  crystalline  lens  of  the  sheep,  slightly  magnified, 
showing  the  three  radii,  and  the  course  of  the  fibres. 

Fig.  14.  Fibres  of  the  lens  near  its  centre,  where  they  are  much 
smaller  than  on  the  surface.     198  diameters. 


rUUeLXVII. 


H.  Miller  del  ad.nal 


E.CKslloog  lith. 


144  EXPLANATION     OF     THE     PLATES. 


PLATE    LXVIII. 

Fig.  1.  Globe  of  the  eye  of  the  sheep,  magnified  3  diameters.  The 
sclerotic  being  removed,  the  choroid  is  seen,  as  well  as  the 
disposition  of  the  stellate  pigment  cells,  which  lie  in  the 
intervals  between  the  venae  vorticosae,  and  which  conse- 
quently follow  a  similar  disposition. 

Fig.  2.  The  same,  showing  the  venae  vorticosae  injected.  Magnified 
3  diameters. 

Fig.  3.  Conjunctival  epithelium,  oblique  view  of.     378  diameters. 

Fig.  4.  A  portion  of  the  ciliary  muscle.     198  diameters. 

Fig.  5.  Conjunctival  epithelium,  front  view  of.     379  diameters. 

Fior.  6.  Gelatinous  nerve  fibres  of  retina.     378  diameters. 

Fig.  7.  Cellated  structure  of  the  vitreous  body.     70  diameters. 

Fig.  8.  Elastic  fibres  lying  on  the  anterior  surface  of  the  posterior 
elastic  lamina.     70  diameters. 

Fig.  9.  A  portion  of  iris,  showing  its  blood-vessels  and  muscular 
fibrillse.     70  diameters. 

Fig.  10.  Epithelium  of  the  crystalline  lens.     198  diameters. 

Fig.  11.  Ditto  of  the  aqueous  humour.     198  diameters. 

Fig.  12.  Cells  of  the  hexagonal  epithelium  of  the  choroid.  Magnified 
378  diameters. 

Fig.  13.  Cells  and  fibres  of  the  stellate  pigment  of  the  choroid.  378 
diameters. 

Fie.  14.  Irregular  pigment  cells  of  the  uvea.     378  diameters. 


ria^Ljyin. 


EXPLANATION     OF     THE     PLATES.  145 


PLATE    LXIX. 

fig.  1.  A  portion  of  the  mucous  membrane  of  the  olfactory  region  of 
the  sheep,  showing  the  apertures  of  the  mucous  follicles,  and 
the  pigment  which  covers  its  surface.     80  diameters. 

Fig.  2.  Blood-vessels  of  the  pituitary  region,  injected.  From  a 
preparation  belonging  to  Mr.  Quekett.     80  diameters. 

Fig.  3.  Denticulate  lamina  of  the  osseous  zone  of  the  lamina  spiralis, 
seen  on  the  vestibular  surface,  a,  free  edge  of  the  teeth ;  b, 
margin  towards  the  axis  of  the  cochlea;  c,  granular  cells 
lying  upon  the  same.     100  diameters. 

Fig.  4.  Tympanic  surface  of  a  portion  of  lamina  spiralis  of  the  cat. 
a,  termination  of  the  cochlear  nerves  at  the  border  of  the 
osseous  zone,  with  capillaries  ramifying  over  them ;  b,  inner 
clear  belt  of  the  membranous  zone ;  c,  marginal  capillary  on 
the  tympanic  surface;  d,  pectinate  portion  of  the  membra- 
nous zone ;  e,  outer  clear  belt  of  membranous  zone,  torn 
from  the  cochlearis  muscle.  300  diameters.  After  Todd 
and  Bowman. 

Fig.  5.  Inner  view  of  cochlearis  muscle  of  the  sheep,  a,  line  of 
attachment  of  membranous  zone  of  lamina  spiralis,  of  which 
a  portion,  b,  remains  attached.  The  surface  below  this  line 
is  in  the  scala  tympani ;  the  surface  above,  the  scala  vesti- 
buli.  c,  projecting  columns,  with  intervening  recesses,  iri 
the  vestibular  part  of  the  cochlearis  muscle.  After  Todd 
and  Bowman. 

Fig.  6.  Plexiform  arrangement  of  the  cochlear  nerves,  seen  in  the 
basal  coil  of  the  lamina  spiralis,  treated  with  hydro-chloric 
acid.  There  are  no  ganglion  globules  in  this  plexus,  which 
consists  of  tubular  fibres,  a,  twig  of  cochlear  nerve  in  the 
modiolus,  its  fibres  diverging  and  reuniting  in  b,  a  band  in 


146  EXPLANATION     OF     THE     PLATES. 

the  plexus  taking  a  direction  parallel  to  the  zones.  From 
this,  other  twigs  radiate,  and  again  and  again  branch  and 
unite  as  far  as  the  margin  of  the  osseous  zone,  c,  where  they 
terminate.  From  the  sheep.  30  diameters.  After  Todd 
and  Bowman. 

Fig.  7.  Compound  cellular  and  calcareous  bodies  of  the  pineal  gland. 
130  diameters. 

Fig.  8.  Granular  cells  and  fibrous  tissue  of  the  pituitary  gland.  350 
diameters. 

Fig.  9.  Villi  of  the  choroid  plexus,  showing  their  epithelium  and  blood- 
vessels.    45  diameters. 

Figs.  10  and  11.  Illustrations  of  the  development  of  fat.  a,  repre- 
sents the  vesicles  contained  in  parent  cells ;  b,  the  same  after 
the  absorption  of  the  parent  cell  membranes.  Magnified  45 
diameters. 

Fig.  12.  Dilated  capillaries  of  olfactory  region  of  human  foetus.  100 
diameters.     From  a  preparation  belonging  to  Mr.  Quekett. 

19 


Plate  LXIX. 


C.Clutoe.del. 


E  C  KeliodP.lith. 


ADDITIONAL    PLATES 


AMERICAN    EDITION, 


150  EXPLANATION    OF    THE    PLATES. 


PLATES  ADDED  TO  THE  AMERICAN  EDITION. 


PLATE    LXX. 

Fig.  1.  Corpuscles  of  lymph,  showing  their  granular  structure; 
although  really  smaller  than  the  colourless  corpuscles  of  the 
blood  (Plate  I.  figs.  1,  2,  and  6),  they  here  appear  larger  in 
consequence  of  being  more  magnified.     800  diameters. 

Fig.  2.  Chyle  from  a  mesenteric  gland ;  the  molecular  base,  with  the 
granular  corpuscles  of  the  same  size  as  those  of  lymph. 
800  diameters. 

Fig.  3.  Fat  vesicles  from  the  arm,  injected.  The  vessels  are  here 
seen  to  be  numerous.  As  yet,  no  terminal  branches  of 
nerves  or  lymphatics  have  been  traced  in  these  vesicles. 
Nerves,  however,  may  pass  through  them  to  reach  other 
points.  Gurlt  has  stated  that  in  emaciated  subjects  the  fat 
vesiclescontain  serum.  Todd  and  Bowman  have  detected 
in  emaciated  subjects  a  spontaneous  separation  of  the  solid 
and  fluid  principles  of  the  contents  of  the  fat  vesicles.  45 
diameters. 

Fig.  4.  Transverse  sections  of  human  hair.     450  diameters. 

Fig.  5.  Cartilage  from  the  finger-joint;  it  exhibits  the  manner  in 
which  the  vessels  on  the  edge  of  cartilage  form  their  termi- 
nal loopings.     80  diameters. 

Fig.  6.  Exhibits  the  contorted  and  looped  vessels  of  the  synovial 
membrane.     45  diameters. 


/ !  .  ,  e  ZXX. 


lY.K.Lia.vrencp  <ie!. 


£.C.ICelloD2.Hth. 


152  EXPLANATION      OF     THE     PLATES. 


PLATE    LXXI. 

The  vascular  surface  of  the  matrix  of  the  nail,  surrounded  by  the 
injected  papillae  of  the  skin ;  the  nail  and  epidermis  having  been 
removed. 

a.  Papillae  of  the  skin  on  the  dorsal  surface  of  the  finger. 

b.  The  lunula :  here  exist  several  rows  of  convoluted  capillaries,  more 

or  less  complex;  these  are  the  horn-vessels  of  Mr.  Rainey. 

c.  Vessels  connecting  the  lunula  with  those  secreting  cuticle.     The 

office  of  these  vessels,  probably,  is  to  secrete  a  substance  inter- 
mediate between  the  horn  and  the  cuticle,  and  thus  cause  an 
intimate  union  between  them. 

d.  Folds,  or  plications  of  the  matrix :  these  increase  in  depth  as  they 

approach  the  end  of  the  finger.  They  consist  of  a  fold  of  base- 
ment membrane,  enclosing  a  series  of  loops  of  vessels.  They 
are  continued  into  the  ridges  of  the  finger,  and  secrete  the  cutic- 
ular  part  of  the  nail. 

e.  Papillae  of  the  tip  of  the  finger.     8  diameters. 

See  Appendix,  page  463. 


Plate  LZXI. 


IE. 


reTice.ileL.  ad.  iud 


Kellogg,  lift. 


154  EXPLANATION     OF     THE     PLATES, 


PLATE    LXXII. 

Fig.  1.  Tendon  from  the  arm.  In  this  figure,  the  vessels  are  not 
seen  to  present  so  uniformly  terminal  loopings  as  in  the 
vessels  of  cartilage.  In  many  instances,  they  seem  to  return 
upon  themselves.  The  same  termination  is  sometimes  seen 
of  vessels  in  cartilage.     60  diameters. 

Fig.  2.  Tendon  from  the  arm,  nearer  its  muscular  union.   30  diameters. 

20 


Plate  ZXXII. 


E.C  Keilood.Mi. 


156  EXPLANATION     OF     THE     PLATES. 


PLATE    LXXIII. 

Fig.  1.  Lymphatic  vessels  and  lymphatic  glands  from  the  spermatic 

cord  of  the  horse,  magnified  8  diameters. 
AA.  The  lymphatic  glands. 

a.  a.  a.  Peripheral,  efferent  larger  lymphatic  vessels. 

b.  b.  An  efferent  or  central  lymphatic  vessel. 

c.  c.  Superficial  net- work  of  delicate  lymphatics,  which  serves  in  part 

to  connect  the  small  flat  gland,  d,  with  the  efferent  vessel,  b. 

d.  A  very  small,  loose,  semi-glandular  plexus  of  lymphatic  vessels. 

e.  Extensive  lymphatic  net- work,  formed  of  the  vessels  of  the  gland, 

and  the  parts  immediately  adjacent. 

f.  Larger  lymphatic  vessels,  passing  over  and  near  to  the  gland,  the 

numerous  valves  of  which  are  obvious. 

g.  Delicate  efferent  lymphatics.     After  Gerber. 

Figs.  2,  3,  and  4,  are  here  introduced  to  exhibit  the  relative  size  of 
the  air-cells  of  the  lungs  at  different  ages:  all  equally  mag- 
nified. 

Fig.  2,  represents  the  capillaries  and  air-cells  of  a  fetal  lung.  In  this, 
no  air  has  yet  entered,  and  the  air-cells  are  observed  to  be 
small,  and  the  structure  dense.     60  diameters. 

Fig.  3,  represents  capillaries  and  air-cells  of  an  infant's  lung.  60 
diameters. 

Fig.  4.  Capillaries  and  air-cells  of  a  lung  of  an  adult.  60  diameters. 
It  is  probable  that  the  microscopic  examination  of  the  lungs, 
in  medico-legal  questions,  as  to  whether  respiration  had 
taken  place,  would  afford  more  conclusive  evidence  than 
could  be  furnished  by  the  usual  tests. 

Fig.  5.  The  branchial  laminae  of  the  eel.     60  diameters. 


Plate  LJXHI. 


~\'.rB  LarvTRiice. 


E.C.Keiinog.  iitk. 


EXPLANATION     OF     THB     PLATES.  157 


PLATE    LXXIV. 

Fig.  1.  Injected  mucous  membrane  of  fetal  stomach.     60  diameters. 
From  a  very  perfect  injection  by  Dr.  J.  Neill. 

The  honey-comb  structure,  exhibiting  large  and  polygonal  cells, 
formed  by  one  or  more  convoluted  capillaries,  is  here  well  shown.  At 
the  bottoms  of  these  larger  cells,  two,  three,  or  more  small  ones  may 
be  seen.  This  honey-comb  appearance  has  been  considered  by  many 
writers  to  exist  throughout  the  entire  mucous  lining  of  the  stomach. 
Dr.  Jno.  Neill  has  made  some  valuable  investigations  on  the  structure 
of  this  mucous  membrane,  and  his  views,  founded  on  the  examination 
of  many  injected  stomachs,  are  published  in  the  Am.  Journ.  of  Med. 
Sciences,  No.  XLI.  (new  series)  for  Jan.  1851.  Figs.  2,  3,  and  4  are 
taken  from  that  paper. 

Dr.  Neill  considers  that  after  the  removal  of  the  epithelium,  "the 
surface  of  the  mucous  membrane  presents  different  appearances  in 
different  portions  of  the  stomach;  this  fact  not  having  been  sufficiently 
appreciated  by  observers,  we  consider  as  one  of  the  sources  of  error 
in  the  ordinary  descriptions  of  this  organ.  By  far  the  larger  portion 
exhibits  various  modifications  of  the  honey-comb  structure,  the  cells 
are  large  and  polygonal  in  some  parts;  in  others,  they  are  smaller, 
deeper,  and  rounder ;  the  ridges  between  these  cells  are  formed  of  one 
or  more  convoluted  capillaries,  and  this  arrangement  of  capillaries  is 
particularly  evident  in  the  rugae  (see  Jig.  2).  The  walls  of  these  cells, 
or  pockets,  are  formed  of  a  net-work  of  capillaries,  which  sub-divides 
each  cell  into  smaller  ones ;  these  cells  are  what  are  ordinarily  called 
the  orifices  of  gastric  glands,  and  the  sub-division  in  the  bottom  of 
each  cell  corresponds  with  the  described  orifices  of  tubuli.  In  the 
antrum  pylori,  the  structure  is  modified,  the  ridges  between  the  cells 
become  larger,  more  elevated  (see  Jig.  3),  and  as  we  approach  the 


158  EXPLANATION     OF     THE     PLATES. 

pyloric  orifice,  conical  villi  make  their  appearance;  these  villi  are 
larger  and  more  numerous  towards  the  pyloric  valve,  so  that  fewer  of 
the  angular  or  polygonal  cells  are  visible  in  their  interstices;  they  are 
not  so  large  as  the  villi  of  the  small  intestine,  but  in  other  respects 
their  external  appearances  are  precisely  similar  (see  fig.  4).  When 
well  injected,  they  seem  to  be  composed  of  capillaries,  closely  united 
by  a  basement  membrane,  and  forming  a  pyramidal  projection. 

"  There  may  be  said  to  be  three  different  appearances  presented  by 
the  microscopic  examination  of  the  injected  capillaries  of  the  mucous 
membrane  of  the  stomach,  when  deprived  of  its  epithelium.  First, 
The  convexity  of  a  large  ruga  will  have  a  comparatively  smooth  and 
even  appearance,  formed  by  convoluted  and  inter-twining  capilla- 
ries. Second,  Any  other  portion  excepting  the  antrum  will  exhibit 
cells  or  alveoli  of  different  sizes  and  shapes,  separated  by  ridges  of 
various  thicknesses,  and  these  ridges  are  composed  of  capillaries 
arranged  in  the  same  manner  as  in  the  rugae.  Third,  in  the  antrum 
pylori,  there  are  conical  villi,  and  cells  exist  in  the  interstices  and  at 
their  bases." 

It  will  be  seen  that  this  description,  which  the  writer  has  verified 
from  examination  of  Dr.  Neill's  preparations,  differs  considerably  from 
those  usually  given  in  the  various  text-books  and  works  treating  of 
minute  anatomy.  Dr.  Neill  is  disposed  to  think  that  the  gastric  villi 
may  be  in  some  way  associated  with  absorption.  What  precise  part 
they  play  in  this  function,  remains  yet  to  be  determined. 

Fig.  2.  Ridges  and  cells  from  the  left  extremity  of  the  fcetal  stomach. 

After  Dr.  J.  Neill.     About  65  diameters. 
Fig.  3.  Deeper  cells  and  more  elevated  ridges  from  the  antrum  pylori. 

After  Dr.  Neill.     About  65  diameters. 
Fig.  4.  Gastric  villi,  from  the  pyloris.     After  Dr.  J.  Neill.     About 

65  diameters. 
Fig.  5.  The  villi  of  the  duodenum  injected  and  the  epithelium  removed. 

The  villi  in  this  portion  of  the  small  intestine   are  broad, 

fiat,  regular  and  shorter  than  in  the  other  two  divisions. 

From  an  injection  by  Dr.  Neill.     60  diameters. 
Fig.  6.  Villi  from  the  jejunum:  here  the  villi  are  longer,  not  so  broad, 

and  less  regularly  disposed.     60  diameters. 


XY7"V 


E  .C. Kellogg,  lith. 


160  EXPLANATION     OF     THE     PLATES, 


PLATE   LXXV. 

Fig.  1.  Villi  from  the  ileum.  From  an  injection  by  Dr.  J.  Neill.  In 
this  portion  of  the  small  intestine,  the  villi  are  more  conical 
than  in  either  of  the  other  divisions,  not  so  flat  as  in  the 
duodenum,  nor  so  long  as  in  the  jejunum.  These  different 
appearances  become  more  or  less  modified  as  we  pass  from 
one  division  of  the  intestinal  canal  to  the  others.  60  diam- 
eters. 
Fig.  2.  Shows  the  arrangement  of  the  vessels  in  the  muscular  coat 
Fig.  3.  Mucous  membrane  of  the  appendix  vermiformis  cceci,  show- 
ing the  capillaries  and  mucous  crypts.  Dr.  J.  Neill,  in  the 
Philadelphia  Medical  Examiner,  for  February,  1851,  has 
accurately  described  the  difference  of  structure  between 
this  appendix  and  the  colon.  In  the  first,  the  crypts  are 
variable  in  size  and  shape,  and  the  distances  between  them 
by  no  means  uniform.  In  the  colon,  the  mucous  membrane 
is  regularly  studded  with  mucous  crypts  or  follicles  of 
Lieberkuhn,  all  nearly  of  the  same  size  and  shape,  and 
almost  equi-distant.  After  Neill.  About  60  diameters. 
Fig.  4.  Mucous  follicles  and  capillaries  of  the  colon.     After  Neill. 

About  60  diameters. 
Fig.  5.  The  vascular  plexus  of  the  Malpighian  body  in  a  healthy  state. 
The  relations  of  the  uriniferous  tubes  to  the  Malpighian 
bodies  are  also  shown.  After  Toynbee.  About  100  diam- 
eters. 
Fig.  6.  The*  vascular  plexus  of  the  Malpighian  body  enlarged,  as 
occurs  in  the  first  stage  of  Bright's  disease:  the  tubuli  are 
also  seen  enlarged.     After  Toynbee.     About  100  diameters. 


Fltjjte  LXXV. 


E:,Pii»iii 


^Qu^Mv  ^JSjJSI  l*'t  ill 


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E.C.Kellogg.lith. 


162  EXPLANATION     OP     THE     PLATES. 


PLATE    LXXVI. 

Fig.  1.  The  enlarged  veins  of  the  kidney  occurring  in  the  first  stage 

of  Bright's  disease.     After  Toynbee. 
Fig.  2.  Another  view  of  the  veins  in  the  same  stage :  here  may  be 

noticed  the  commencement  of  the  stellated  condition  so 

characteristic  of  the  more  advanced  stages  of  the  disease. 

After  Toynbee. 
Fig.  3.  The  stellated  appearance  of  the  veins  in  the  advanced  stage 

of  the  disease.     After  Toynbee. 
Fig.  4.  Granulation  on  the  surface  of  the  kidney  in  an  advanced 

stage  of  Bright's  disease.     After  Toynbee. 
Fig.  5.  A  urinary  tube,  very  much  dilated,  in  the  third  stage  of  the 

disease.     After  Toynbee. 

All  the  above  figures  are  magnified  about  100  diameters. 

21 


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Place  LXXV1 


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EXPLANATION     OF     THE     PLATES.  J(J3 


PLATE    LXXVII. 

Fig.  1,  represents  a  magnified  view  of  a  vertical  section  of  the  skin 
under  a  power  of  seventy  or  eighty  diameters:  g.  g.  Sudo- 
riparous glands  imbedded  in  fat  vesicles ;  d.  the  ducts  of  the 
same  passing  in  a  flexuous  course  through  the  areolar  tissue 
to  de,  the  dermic  portion  of  the  skin ;  two  of  these  ducts  are 
represented  cut  across.  On  the  right,  a  duct  is  represented 
cut  open  at  its  upper  part,  and  its  parietes  are  seen  to  be 
continuous  with  the  basement  membrane  of  the  papillae 
which  bound  it  on  each  side,  assuming  as  it  approaches  them 
an  infundibular  form.  Between  the  same  two  papillae  may 
be  seen  the  lowest  portion  of  the  epidermic  part  of  a  duct, 
at  first  very  indistinctly,  and  without  any  defined  continuity 
of  structure  with  the  duct  below — gradually  assuming  a 
spiral  form,  and  having  the  scales  of  which  its  walls  are 
composed,  arranged  parallel  with  the  axis  of  the  passage. 
The  other  ducts  are  seen  dipping  down  between  and  behind 
the  papillae ;  at  n,  may  be  seen  the  nuclei  on  the  basement 
membrane  of  the  papillae,  which  at  nc  are  developed  into  a 
layer  of  nucleated  cells,  forming  the  lower  stratum  of  the 
epidermis,  ep,  through  which  one  complete  sudoriferous  pas- 
sage, p,  may  be  seen  passing  to  the  surface,  together  with 
portions  of  others.  The  spaces  between  these  passages  have 
been  cut  away  in  the  preparation,  by  which  the  direction 
of  the  scales  of  the  epidermis  not  in  the  vicinity  of  a  passage 
are  seen  to  be  horizontal,  but  variously  inclined  where  situ- 
ated in  its  vicinity.     After  Rainey  and  Ralph. 

Fi£.  2,  is  a  magnified  view  (220  diameters)  of  the  dermic  part;  d,  the 
dermic  portion  of  a  duct  cut  open  at  its  upper  part,  also 


164  EXPLANATION     OF     THE     PLATES. 

with  the  basement  membrane  of  the  papillae  on  each  side 
continuous  with  it;  p,  the  epidermic  portion  of  the  duct 
between  the  papillae,  exhibiting  a  scaly  structure  almost  at 
its  commencement;  n,  nuclei  on  the  basement  membrane, 
at  nc,  developed  into  nucleated  cells,  and  forming  together 
the  lower  part  of  the  epidermis ;  above  which,  at  ep,  may  be 
seen  the  commencement  of  the  scaly  layer  of  the  epidermis ; 
three  papillae  with  a  vascular  loop  in  each.  After  Rainey 
and  Ralph. 

Fig.  3.  Mucous  membrane  of  the  gall-bladder ;  from  an  injection  by  Dr. 
Jno.  Neill,  of  Philadelphia  (see  page  358).     50  diameters. 

Fig.  4.  Transverse  section  of  the  muscles  of  the  tongue.  The  fibres 
are  of  the  striped  variety,  but  are  not  here  sufficiently  mag- 
nified to  show  the  lines.     45  diameters. 


Plate  LXXVII. 


p 


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166  EXPLANATION     OF     THE     PLATE 


PLATE    LXXVIII. 

Fig.  1.  The  terminal  loopings  of  vessels  in  the  cornea  of  the  eye  of  a 
pig.     45  diameters. 

Fig.  2.  The  conjunctival  epithelium  of  the  cornea  in  the  eye  of  the 
viper,  showing  its  vascularity.  In  animals  that  cast  their 
skin,  this  lamina  is  shed  with  the  cuticle  of  the  body.  In 
the  human  eye,  this  lamina  is  not  vascular.     45  diameters. 

Fig.  3.  Vessels  of  the  choroid  coat  of  the  fetal  eye,  near  the  ciliary 
processes.     45  diameters. 

Fig.  4.  Ciliary  processes  of  the  human  adult  eye,  showing  their  form 
of  origin.  From  an  injection  by  Dr.  Jno.  Neill,  of  Philadel- 
phia.    45  diameters. 

Fig.  5.  Mucous  lining  of  the  unimpregnated  uterus  of  the  sow.  35 
diameters. 

Fig.  6.  Mucous  lining  of  the  impregnated  uterus  of  the  same  animal, 
showing  how  the  rugse  become  developed  during  gestation. 
35  diameters. 


Plwte  LXXVJ7I 


HA  J.  Id. 


"W.H.L.ael 


C  Kellofiq  lift 


168  EXPLANATION     OF     THE     PLATES, 


PLATE    LXXIX. 

Fig.  1.  A  tuft  from  the  fetal  portion  of  the  human  placenta.    45 

diameters. 
Fig.  2.  Papillae  of  the  gum:  a  portion  of  the  tooth  is  represented  to 

exhibit  the  manner  in  which  the  papillae  surround  it.     From 

an  injection  by  Dr.  Neill.     45  diameters. 
Fig.  3.  Papillae  from  the  lip:  these  are  observed  to  be  rather  longer 

and  more  prominent  than  in  the  gum.     From  an  injection 

by  Dr.  Neill.     45  diameters. 
Fig.  4.  The  arrangement  of  blood-vessels  in  the  mucous  membrane 

of  the  trachea.     45  diameters. 
Fig.  5,  shows  the  vascularity  of  the  buccal  membrane.     60  diameters 
Fig.  6,  shows  the  vascularity  of  the  mucous  membrane  of  the  bladder 

60  diameters. 


,     Plate  ZXXIX. 


H.A.D  rlel 


.v  r.  uawr.Ti.ct-  it*i 


E  C.Kallose.Mi 


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